texts: What is the equation for calculating static thrust?

texts:
I'm building a quadcopter as my bachelor's degree thesis. I'm having trouble finding a reliable equation for calculating the static thrust for a quadcopter. The equations I have found give me ridiculous results. I know that it's difficult to derive such an equation and I know that there are online calculators (like this). But how do these calculators calculate static thrust? There has to be an approximate equation somewhere. This is what I'm asking. I don't mind the equation(s) that lead me to there, I would just like to know them.

Edit: More information

The following snapshot is taken from Mathcad software. It's various equations i have gathered from supposed trustworthy websites. These equations lead me to the calculation of static thrust. I think the equations are pretty self explanatory. Thank you.

Components of the quadcopter: Battery, ESC's, Motors, Propellers, frame

Various useful websites that i've found most equations: 1, 2, 3, 4


texts: What happens to the neutral point of a fighter jet during supersonic flight?

texts: I understand that for a fighter aircraft, it would have to be inherently unstable. To do this I believe that the neutral point needs to be aft of the cg. I was told that during supersonic flight this relationship might be different. What would change in supersonic flight?


texts: I know the pressure distribution on an airfoil but not shear stress. How is shear stress distributed on an airfoil?


texts: Has the financial situation of an airline ever negatively impacted safety?

texts:
Has a bad financial situation, or simply being greedy, impacted negatively the safety of an airline or even caused lethal accidents?

Notice that this is not necessarily a question about low-budget airlines like  Ryanair and EasyJet, JetBlue, or Spirit. Low ticket price does not imply the company is in a tight financial situation. No frills does not imply cutting costs at the wrong end.

Although regulations are the same for all, there are certain scenarios where this seems to matter. No airline will be allowed to skimp on safety issues, but wouldn't having less resources imply:

Hiring cheaper pilots, which fulfill minimal requirements, and not much else.
Flying routes that are open, but less safe, like Ukraine until recently.
Putting more pressure on pilots to fly against their judgment.


texts: Should time in turbojet aircraft be logged as complex?

texts:
I was having a discussion with a colleague about what aircraft qualify for logging complex time. We were discussing whether or not time flying transport-category turbojet aircraft qualified as complex according to the regulations. It's probably irrelevant at that point in a career, but my interpretation is that turbojet aircraft are not complex. 14 CFR 61.1 defines a complex aircraft as one having a retractable landing gear, flaps, and a controllable pitch propeller. It goes on to give some provisions for control computer or FADEC, but it still mentions propellor controls. In turbojet aircraft you just set the throttle, even if there are a lot of computer-controlled variables changing in the engine.

While it's not a jet, the Daher-Socata TBM 900 single-engine turboprop airplane has a single throttle quadrant and an automatically controlled propeller. It's still considered complex under the regulations even though there's no lever to adjust the prop and it's still complex. I give this example only because it has a single throttle lever and is still complex.

I'd love to get more interpretations on whether turbojet aircraft are technically complex according to the definitions of 14 CFR 61.


texts: What could cause a low-pressure compressor first stage blade of a turbofan engine to bend forward?

texts:
What could cause a low-pressure compressor first stage blade of a low-bypass turbofan engine to bend forward?

I also noticed rotor path rubbing in the 9 to 12 o'clock portion (while usually this can happen only in the 6 o'clock area).


texts: What is this tab above the DC-10's #2 engine?

texts:
What is this big rectangular tab (?) thingy extending backwards just above the DC-10's #2 engine? What does it do?

(wikimedia.org, picture modified to point out the tab thingy)


texts: What are the handling effects of converting a dihedral wing to polyhedral?

texts:
I'm looking at plans to build a radio controlled (RC) glider that is launched by rocket boost mainly as a park flyer. I've been given a set of plans for a model that is a dihedral wing (see attached photo), and I am thinking converting it to a polyhedral wing, as I read that polyhedral wings are more stable for people new to flying as I am.

The new wing shape (I haven't drawn it out yet), would have a flat section over the fuselage acting as a partial cover for the rc components, then a 6 degree angle from there to mid point of the wing, and then another 6 degree angle to the tip.

Wing length and total angles/measurements would be the same, as would the airfoil (Which can be seen in the rib segments on the plan). My other option is simply adding the central flat fuselage cover section, and leaving the rest of the wing as is. (One note, the reason for the thinning of the rib sections in the front is that it is a partially built wing, there is a balsa skin over those parts, then the entire wing is coated in a lightweight monokote type material).

Is there any value in making this change to a polyhedral wing, or is it mostly a wasted effort that I shouldn't worry about doing?

Wing section (I have full plans if other angles are desired):


texts: How is a transonic aircraft longitudinal stability different than a subsonic and supersonic aircraft?

texts: /I would like to know-how is the longitudinal stability is achieved between different aircrafts


texts: Can you tell ATC you are a "student pilot" when you are not?

texts:
Many pilots who are not native English speakers have a hard time when they start flying in the U.S. because of the pace and sometimes elaborate instructions given to pilots by controllers.

The advice given by instructors is to tell the controller that you're a student pilot, even though you may be a fully licensed (private) pilot. The effect should be that the controller will be more lenient towards the pilot and speak slower.

I would first of all like to know if it is legal to tell a controller that you're a student pilot even if you're not (I know, all pilots should see themselves as students for the rest of their life, but that's another topic).

Also, isn't there a chance that you'd get refused entry in class B airspace because you're announcing that you're a student pilot?


texts: What determines CFD accuracy for aircraft design?

texts:
Do CFD results depend on the knowledge of the person who is working with software or do the final results just depend on computer power and CFD software?
Does one need to know aerodynamics to do serious CFD work or is everything in the CFD software?


texts: Where is the fire suppression material injected into a jet engine?

texts:
This question is regarding the P&W 4000 engine that was involved in the recent incident on UAL 328, but it doesn’t have to be specific to that engine.
From what I gather in this incident the fire continued after both fire suppression bottles had been deployed. I’m wondering where exactly does the suppression material go into the engine? Does it all flow into the core or is it distributed to different places. Does the loss of the cowl render it ineffective? I expect that halon would only work in an enclosed space. It appears that the fire in this incident was outside the core and without the cowl there wouldn’t be much that could be done in flight to put it out.


texts: Why are the Convair 880's yokes shaped differently from each other?

texts:
Looking at this picture of a Convair 880's flight deck...

(Image originally by the San Diego Air & Space Museum at Flickr, via Wikimedia Commons)

...the captain's and first officer's control yokes have quite different shapes; the captain's yoke is round, like that of an automobile or a 1930s propliner, while the first officer's yoke has the familiar W-shaped yoke, complete with buttons on the yoke's horns.

Why the difference between the two yokes?  Is it to optimise the captain's yoke for the duties of a pilot flying, and the first officer's yoke for the duties of a pilot monitoring?  Or something else?


texts:
I've been going over the new Master Minimum Equipment List (MMEL) for Textron Aviation Model 500 Series Citations and on page 70 an Electronic Flight Information System (EFIS) 5 or 3 Tube System is mentioned but I can't find any information or pictures of it online.

Can someone explain?


texts: Are there any manoeuvres that would be considered unrecoverable in a General Aviation / Training Aircraft?

texts:
I'll try to make this question a little more manageable by applying the following constraints, though of course all answers would be welcome:

By "General Aviation / Training" aircraft, I'm talking primarily about normal SEP's of the kind that we see daily and would require no more than a check-ride before hiring. No experimentals, warbirds, super rare aircraft etc - though MEP's and Complex Aircraft would count.
I'm ignoring low level maneuvers. We all know a stall at 100ft is going to be tricky, though on the other hand, if something is going to require 5000' at a minimum to recover from then that's going to be fatal in most cases.
Let's ignore mechanical and airframe failures that occur prior to the incident.
I'm assuming Weight & Balance are within the normal category of the POH (As opposed to utility or aerobatic).

Beyond that, the question is what it says on the tin. Is there anything stupid that I can do as a Pilot in a Single Engined Piston GA aircraft that I simply won't be able to recover from, even with a few thousand feet to do so?


texts: How much does each engine on a Boeing 747 weigh?

texts: The Boeing 747 weighs 404,600 lbs in total, but how much of that does each engine take up?


texts: Why do all commercial aircraft have carpets?

texts: When flying I noticed that all the commercial aircraft I have been on use carpets as a floor covering. But why? If you fly in an older aircraft it looks worn out and it is susceptible to stains etc. Why do they not use one of the hard flooring options like linoleum?


texts: Why might DTK on GPS not match depicted course on approach plate?

texts:
I hope this isn't a dumb question, but I haven't flown a whole lot of GPS approaches and today I observed something that I cannot explain:  There was a 2 degree split between the Desired Track (DTK) displayed on the GPS, and the inbound course shown on the approach plate.
If it matters, the approach was the RNAV 16 Y approach at KRNT, and I was using my club airplane's Garmin GTN 650.  The database in the GPS was up to date, and my approach plate in Foreflight was current.  DTK showed 159, and the plate showed 157.
Not a big difference, but they ought to be the same, right?
At first I thought it might be displaying track direct from my present position, but I had early turned the fix a little coming from the west, and was lined up a bit right which would have made the course needed to correct a few degrees less than 157.
And as I made minor course corrections back and forth across the final approach course the DTK never wavered.
Is there a good explanation for this difference that I'm just not aware of?


texts: How much of an airline's costs are labor costs?

texts:
What percentage of a commercial airline's costs are labor costs? Can an airline run a low-cost operation without reducing the wages for crew and pilots, or subjecting them to long shifts? E.g. Southwest has a history of paying good wages; also personnel is unionized there.

Are there other ways that an airline can reduce costs? Simplified fleets, aircraft utilization, good revenue management, come to mind.


texts: What is the exact definition of a "crew duty day"?

texts:
How do you define a crew duty day? When does it start and when does it end? Also what are the legal limits (in other words how long can a crew duty day last in terms of hours)?.

Edit: Here is a link I found, which basically defines what a Duty period is for the Australian Civil Aviation Safety Authority: https://www.casa.gov.au/standard-page/duty-time-flight-time-and-flight-duty-period.

My question: does each country define its own rules for what constitutes a duty day or do you have standardized set of rules. What happens when you fly say from the US to Australia? Which set of rules prevail?


texts: Can an automatic gearbox improve engine transmission for an ultralight?

texts:
I am working on my dream to build and fly an ultralight aircraft so I wouldn't like to know the following:

Does adding a motorcycle automatic gear box to an  engine improve on the strength for an ultralight aircraft?  The engine in question is a 4 stroke, OHV, single cylinder, 440cc gasoline engine with a TCI ignition.  It produces 18hp at 3600 RPM,  torque 3.0 kgm/2500 RPM (21.7 lb ft), ignition TCI, gross weight 37 kg.
What should be the tail, flaps and wing measurement proportions for such engine?

Thank you


texts: What is the aerodynamic effect of a panorama (skydeck) near the tail section of a commercial airline?

texts:
A company called Windspeed Technologies posted the following concept video of a panorama seating option aboard a commercial plane.

From the limited understanding I have of the phenomena called flow separation, such a structure on the fuselage may induce separation.

The sphere example here is just an approximate representation for the semi-ellipsoid.

The reason I am asking this question, is because the ellipsoid is relatively near the tail section of the plane. It does not seem like a good idea to have a turbulence inducing structure that close to the tail.

How will this addition to the plane fuselage effect the air flow ? Worst case, can it cause navigation problems due to turbulence near the tail section ?


texts: What sort of issues related to extreme heat (115°F, 46°C plus) would prevent takeoffs or landings?

texts:
I recently flew into and out of McCarran Airport Las Vegas (LAS) and a local told me that they never report the air temperature at the airport above 115°F (46°C) because the FAA does not allow landings above that temperature.

What sort of issues do large passenger jets (or small for that matter) have to deal with in high temperature environments either taking off or landing?


texts: How does a failed turn and slip indicator behave if the gyro isn't spinning at all?

texts:
I have my own theories, but I have never experienced a turn coordinator or turn and slip indicator's gyro failing first-hand.

If the gyro isn't spinning, would the instrument behave like a weak accelerometer but on a different plane of movement, or would it just do nothing at all?

For example, would the weight of the motionless gyro of a turn and slip indicator resist movement laterally when the plane is rolled and cause a momentary turn indication from roll or are the centering-springs strong enough to overcome virtually any inertial resistance offered by the weight of the gyro?

Another way of asking this is if you held a turn and slip indicator unit in your hand with the display window facing your palm and you rotated (rolled) the unit side-to-side rapidly in sort of a door knob turning motion, would the turn rate indicator needle tilt at from the center position on the display at all?


texts: What is this device mounted on the fuselage of Lufthansa planes?

texts: I noted the device shown in the photo mounted on top of the fuselage near the tail. The photo shows a smaller airbus (I think) but it is also present on several A380ies, and a Boeing 747. In fact, most, but not all Lufthansa planes (observed at Frankfurt airport) seem to have this but I haven't noted it yet with other airlines.


texts: What to do to maintain my Spanish ULM (GA) gyroplane licence valid in the USA when moving there?

texts: I have an ultralight gyroplane (GA) Spanish license. What sort of conversion or validation process do I need to follow to be able to continue flying after moving to the USA?


texts: What is the best way to give ATC a position report using only a VOR (no DME or GPS)?

texts:
While cumbersome, is it permissible when asking for a pop-up IFR clearance to state, at the intersection of WWW radial XXX and YYY radial ZZZ?

Obviously, during VMC, you have your pick of visual checkpoints, but in IMC, are there any better suggestions?

Additionally, if you are near a navaid or published intersection, and take a guess at your distance from it, how far off would your guess have to be before ATC wouldn't really even consider it helpful?


texts: I have seen that aircraft mostly use CFRP (carbon fiber reinforced polymer) in large composition. But in some places like the leading edge of the wing, fin, and radome, GFRP (glass-fiber reinforced plastic) is used, why?


texts:
Consider the above figure:

Why the search is conducted to the red boxed area in the figure. while the actual route of Flight MH 370 is the green line.

The last known position is on the flight path, then

Why not search on East/South China Sea & Bay of Bengal ?


texts: Is a compressor cascade just the representation of the blade ring of an actual turbomachine? What is the difference between linear cascade and annular cascade? A diagram or a reference would be great.


texts: Could the SR-71 Blackbird be used for nearspace tourism?

texts: The Blackbird had two seats onboard. Could it be reactivated for nearspace tourism, placing a paying tourist in the other seat? If no, why not or why isn't it being proposed? In leveled flight, the Blackbird flew up to 90,000 ft (27 km) MSL and faster than Mach 3. In a ballistic parabola it could probably reach an even much higher altitude, and on the parabola's top you'd start to experience weightlessness, go above most of the ozone layer, see a black sky with some stars in daytime and the thin blue atmosphere of Earth. An exceptional experience for many.


texts: Who opens an airliner's door first after it lands?

texts: I know this is a trivial question, but since I always sit near the back of the plane, I can't see what happens up in the front. Whose responsibility is it to open the cabin door once the aircraft has pulled up to the jet bridge?


texts: Why would a flight no longer considered airworthy be redirected like this?

texts:
I ran across this tweet covering the saga of Smartwings 1201, a 737 MAX 8 that was apparently redirected from Prague to Ankara after the MAX was grounded by the EU.

(flightaware.com)

It seems like an odd decision to do this. The plane had to divert and apparently spent quite a long time in circling before it was allowed to land in Turkey. Why was it not allowed to land at Prague as scheduled and be grounded there?


texts: Why do some Air Forces not allow Color Blind Pilots?

texts: Some Air forces (Like the Indian Air force) do not allow Color Blind pilots. Is this local only to the IAF or a global procedure? Also, are there any regulations regarding commercial pilots not being Color Blind?


texts: Why don't commercial jet aircraft have a break-apart, parachute escape system?

texts:
Imagine that the pilots on a jet aircraft determine that it will crash. Consider what would happen if the design of the craft allowed it to:

Break into four pieces
Each piece is pressurized independently
Each piece is attached to large parachutes, similar to how they bring down Soyuz or other space crafts returning to Earth

Would that not work so that passenger jets are brought down safely instead of crashing?


texts: Has reversing the active runway direction ever led to lined-up aircraft taxiing to the other end of the runway?

texts:
I was in an aircraft yesterday waiting for its turn in the departure queue on the taxiway and noticed that the windsock was showing a direction approximately 30 degrees but directed along the direction we were entering the runway in. i.e. The parallel component would point in the take-off direction & not against it.

Made me wonder: Are there instances when lined up aircraft have to be made to taxi to the other end of a runway due to a last minute wind direction reversal?

Never happened to me, nor seen it mentioned in any ATC conversations / videos online so made me wonder.

Of course, if the parallel component is smaller than the allowable tailwind for the aircraft then  I guess it does not matter?


texts: Is the Bendix/King KMD-550 airplane icon always oriented to the north?

texts:
I have a 2001 Cessna 182T with King avionics. The KMD-550 moving map display correctly shows "track up" but the little airplane icon is always pointed to the north.

How can I set this so that it points track up as well, or is there some kind of fault with the unit?


texts: Why do some airlines operate fleets so diversified?

texts:
When you have a look at the fleets from big airlines like United, Delta, Lufthansa, BA, AF, etc. it seems that they have almost every model Boeing and Airbus released in their fleet. And my question is, why?

What I assume is that such a big variety would increase the costs for maintenance, training, etc.

Thus, for example, why use the A330 as well as the 777? Why operate both the A320 and 737?

For me as a passenger it is comfortable because I like to test and review different aircraft; but for these airlines' Operations divisions it must be horrible!

I know there are probably reasons to do so otherwise they would not have this variety. What are these reasons?


texts: For how long are state and federal aircraft registrations valid?

texts:
How long is a state registration valid for and how long is a federal registration valid for?
and for state I mean North Dakota if any of you know where to look for that.


texts: Does Airforce one carry missiles to protect itself and its passengers?

texts:
Do the VC-25 aircraft used for Air Force One carry missiles to protect itself and its passengers?

If so, can these missiles be fired at potential threats?


texts: Can a holder of a G4 Visa legally receive flight training and/or acquire a Private Pilot Licence?

texts: I am planning to attend a flight school and acquire a PPL, but I am currently staying in the US with a G4 Visa. Am I allowed to receive flight training legally?


texts: On an inverted aircraft, is the ILS glide slope sensing reversed?

texts: If I'm halfway through a barrel roll on final descent, on an ILS, will I get reverse sensing on my glide slope indicator?


texts: Which device for VTOL flight costs the most to maintain for a given number of flight hours?  A tiltwing mechanism?  A 2D thrust-vectoring nozzle (vectoring only between VTOL position and cruise position)?  A helicopter rotor mechanism?


texts: What is the brace position for cockpit crew?

texts:
I have read a number of times the CVR transcript of US Airways 1549. Just before impact, they say:

  we're gonna brace

I know what is the brace position for passengers, but I'm not sure about how cockpit crews would adopt it. For Airbus aircraft (as this flight was) I think it could be done more or less the same way as passengers, but what about in Boeing or other yoke-equipped cockpits? Wouldn't the brace position interfere with critical flight controls?


texts: Why do jet planes with multiple engines have separate throttle levers for each engine?

texts: What are the reasons to not just use one throttle lever for all engines?


texts: Popular forum feedback on the A-10 Warthog is that it is held in high esteem however I also read that it is no longer being manufactured. Is this true and why would a highly successful combat aircraft be discontinued?


texts: What are the differences between each ILS category?

texts:
I want to know the characteristics of the different categories of Instrument Landing System (ILS): CAT I, CAT II, CAT IIIa, CAT IIIb and CAT IIIc. What are the differences between them?

(This question only covers CAT III).


texts: Can a GPS waypoint be used when filing a VFR flight plan?

texts: This probably equally applies to IFR flight plans, but the general question is can arbitrary (unrelated to an airway or named fix) GPS coordinates be used in the route on a flight plan?


texts: What bank angles are used for IFR operations?

texts: ICAO requires or recommends 25 degrees bank angle. On Boeing auto pilot it's possible to set 30 degrees to be used. What bank angles usually are used for Holding, ILS intercept en-route when flying manually and on autopilot? Any EASA rules in this field?


texts: What's the meaning of "straight and level"?

texts:
Indeed a very strange question.

My understanding of straight and level is: The aircraft is flying at a constant heading and constant altitude, and maybe at a constant speed, and this has nothing to do with the aircraft attitude. However I was reading this in "Big Red Today":

  "If you just keep it straight and level, the chances of surviving are
  better," Ms. [...] said. "But as soon as you start to turn, you put
  yourself at risk of a stall-spin.

Here this is clearly about maintaining the aircraft neutral attitude while landing, so losing altitude, and probably speed.

Is this use of "straight and level" correct? What is the definition of straight and level, if any, regarding heading, attitude, speed, altitude?

Note: Please explain for all parameters mentioned above to remove all ambiguities.


texts: Has a commercial or military jet bi-plane ever been manufactured?

texts:
Are there any, or have there ever been any commercial/military jet bi-planes?
What would be some of the major advantages vs disadvantages if one was built?

Electric radio controlled ducted fan model.

University of Tokyo concept model.


texts: Requirements for Steady Level flight at various speeds

texts: Let an aircraft in a steady level flight be trimmed at certain speed. A level and steady flight at a higher speed can be achieved by changing throttle and elevator together ( and not just by changing elevator or throttle alone). How?


texts: In the rare event that the U.S. DOD shuts off the GPS, what's the alternative?

texts:
In the U.S., the Department of Defense along with other Federal Agencies of the Government operates & maintains the GPS.

In the rarest of the events, if for any reason whatsoever, the Government decides to shut off GPS provisioning (even temporarily), what are the consequences/alternatives for the aviation industry?

What percentage of the industry solely relies on The GPS to operate?
What percentage of the industry has enough alternative navigation means to continue operation regardless The GPS?

On a broader spectrum, I'm also curious about the aviation industry's reliance on GNSS and what could happen in cases of global disaster, wars, cyber-wars etc. (all of which are not impossible).


texts: Where can I find accident statistics on zero gravity flights?

texts:
I am investigating the option of booking a zero gravity flight with a commercial airline. But I am a nervous flyer.

Do any of the airlines offering this have a 0% accident / fatality record?


texts:
Can a civilian aircraft pilot see a missile coming?

By "civilian aircraft," I mean planes that were not equipped with flares that fire when rockets approach  or any similar anti-missile systems.  If these missiles can be detected, can the pilot take any evasive measures?


texts: What airplane does this vintage instrument panel come from?

texts:
Can anyone please tell me what this is from?

It looks like it's military. I have a few panels that came with this and gauges (not if it's a b-16)


texts: What's the relationship between AOA and airspeed?

texts:
We know that any aircraft will stall at its stall speed (for a specific weight, CG position, etc.) but also, that the same airplane will always stall at the same angle of attack.
I´ve read that IAS is just the easy way to control AOA, because in reality it's all about AOA and nothing to do with airspeed. That when changing IAS we are changing the relative wind and thence AOA. On the other hand, I know that the critical AOA doesn´t change with weight (it will always be the same for a given airfoil) but the stall speed will.
There are also high speed stalls... I'm confused. Can we get into a stall without reaching the critical AOA? What's exactly the relationship between AOA and IAS?


texts: How can luggage be lost if it has a bag tag?

texts:
I lost a bag on a flight from BKK -> ARN -> CPH two weeks ago. I immediately filed a report at CPH when the bag hadn't arrived after more than an hour of waiting. Since then there has been no updates of the bags whereabouts on the tracing website.

As a layman, the only reasonable explanation for the bag being missing for more than a few days seems to be that the luggage tag has somehow fallen off the bag. If the luggage still has a tag and is sitting somewhere in an airport - be it at BKK, ARN or CPH - surely someone would have noticed it by now and scanned the tag?

However, when reading about why luggage gets lost, and especially seeing photos of lost luggage at auctions, it seems that it's entirely possible for a bag to still have its tag with barcodes intact and yet be "missing".

How can this be? Surely the system must be built in such a way that a luggage handler can scan the bag tag at any time and either find the missing luggage report or the contact details of the passenger? Or is the luggage handling identification system a lot dumber than I imagine? I read somewhere that "after 3 days the barcode is reused for other passengers luggage", which sounds too stupid to be true.

It would be interesting to know how it works, perhaps someone here can shed a light?


texts: Are the advantages of a coaxial rotor on a helicopter also applicable to a ducted fan?

texts:
A coaxial rotor helicopter is connected to the same engine and has the advantage of anti-torque and a +/- 25% increase in lift.
My question is if a coaxial ducted fan connected to the same engine would also have a +/- 25% increase in forward motion ?


texts: In the Lockheed Martin Flight Services system, what are MIFR, MVFR, YFR and ZFR flight rules?

texts:
When I file a flight plan I can file under either IFR or VFR flight rules. However, the Lockheed Martin Flight Services website has the following options in addition to IFR/VFR:

MVFR
MIFR
YFR
ZFR

1 and 2 are only available for US domestic flight plans; 3 and 4 are only available for ICAO plans. What are all these options and when should I use them?


texts: Why is there a need for a Top Altitude in FAA's SIDs?

texts:
I am examining some of the FAA's SID charts and, as far as I can deduce, each SID provides information concerning the altitude when it is necessary and, if not changed by the controller, each transition/route description will end with something such as "Maintain X altitude etc." which seems that it is the same as the Top Altitude.

Since this information is written in SID's textual description as "Maintain X altitude", why is there a need to exist also separately as Top Altitude?


texts:
With regards to the text below, can someone offer either advice or a link to a website/document that would help decode ACARS messages.

I am ok with the following:

QU - ACARS "to" address
Q - ACARS "from" address
FML - data from left hand FMS
FI - Flight Identifier
AN - Aircraft Number
IGW1 - Iridium server identifier
130710 - date/time of data package sent
F57A - package identifier

So that leaves the DT QXT info plus the hex from ADS line.

QU REKASCC
.QXSXMXS 130710
FML
FI AB1234/AN G-INFO
DT QXT IGW1 130710 F57A
-  ADS.TF-
AMU0719603F0D994AFD09849D0D1B05B71C71CAFC85601FFFFF55554AFC800E0EB0F57FF40F0E29AA3FF4100EB11E0E8EFE


texts: Pitching moment as a pure moment and its measurement with a homemade force balance

texts:
In mechanics, we learn that a force $F$ acting at a certain application point $P$ can exert a torque (also called moment of the force) about another arbitrary point $Q$ in the plane, i.e. $\tau= F \times PQ$ where $PQ$ is a distance vector.
It is possible to move the force $F$ off its application point $P$ and off its line of action and transfer the force the point $Q$. But to keep things equivalent, a couple (two equal magnitude forces, oppositely directed separated by distance $PQ$) must be added. The couple produces a pure moment, i.e. a nonzero moment that does not depend on the reference point (called pole). The new system (a force + a couple) is equivalent to the original one (single force $F$ located at $P$).

Let's contextualize this discussion to an airfoil and its the pitching moment:
The force is the lift force $L$ which acts at the point $CP$ located a distance $x_{CP}$ from the airfoil leading edge $LE$ for a specific AoA. It is mathematically possible to move the resultant lift force $L$ from $CP$ to the quarter point $AC$ located at $x_{AC}$ but we need to add a pure moment (couple force system) to keep the physics equivalent. The net pitching moment about $AC$ is just the pure moment due to the couple since the force $L$ exerts zero torque about $AC$ (zero lever arm).

Interestingly, as we change (for ex. increase) the AoA, the magnitude of $L$ increases and the distance $x_{AC}$ decreases getting closer to the $LE$. We can even in this case transfer the force $L$ to the point $AC$ along the chord (zero torque due to $L$ about $AC$) and add the pure moment. This moment will be CONSTANT and exactly the same as the pure moment for larger or smaller angles of attack. Why? Because even if the two forces in the couple are larger, their mutual distance gets smaller for a larger AoA keeping the overall pure moment the same.

Is that correct?

If we then shift the AoA to the zero-lift point, then $F=0$, leaving us with the force couple only and the same pure moment (which is the sum of all the remaining forces along the chord which balance at this angle of attack) that existed for all other angles of attack.

As long as we define the reference point to be the quarter point $AC$, all variations in lift $L$ with AoA have no moment around this point. If, however, we choose some other point as your reference point, the change in the lift force with angle of attack will add a moment, so your pitching moment is some constant value plus an angle-of-attack-dependent contribution.

Experimentally, when building a force balance that measures lift and the pitching moment using two load cells, I envision using two vertical supports attached to the wing and connected to load cells. For a certain AoA, the lift force will be given by the vector addition of the two forces, $L_{total}=F_1 +F_2$ recorded by the two load cells connected to the supports (I think).

But how would we measure the pitching moment? Where should the two supports be connected under the wing to calculate the pitching moment? How far should the supports be from each other? Essentially, how would I use the forces $F_1$ and $F_2$ to measure the pitching moment?

I think it could work this way but I need some validation: Considering the reference point to be the quarter point $AC$, the two forces $F_1$ and $F_2$ and their torques about $AC$ can be made equivalent to a single force $L_{total}$, the total lift $L_{total}$ passing through $AC$ and generating zero moment, and a single couple producing the nonzero pure pitching moment. For different angles of attack, this pure pitching moment "should" be the same...Will it?

Thanks!


texts: Can UHMWP be used as composites for aircraft impact susceptible areas?

texts:
Can Ultra High Molecular Weight Polyethylene (UHMWP), be used as composites for aircrafts impact susceptible areas?
I did some research but could only see UHMWP being used as a hybrid with graphite/ carbon.
I have two questions is it possible to make composites purely of UHMWP and epoxy?
And, why use UHMWP with carbon, as it already has good characteristics alone?


texts: What is the difference between directs and shortcuts in the Route Availability Document?

texts:
I am studying about directs and shortcuts in aviation. While flying, an airplane can move from an airway to another by using directs or shortcuts.

What I want understand is the difference between directs and shortcuts.

I know some of the information is contained in the RAD (Route Availability Document) but I don't understand if contains infos about direct or shortcuts or both.


texts: Which incidents did not result in accidents because of the actions of the second pilot on board?

texts:
In accordance with 14 CFR §25.1523 and §121.385c3, commercial airline aircraft must be operated by at least two pilots. This provision mainly bases on workload and pilot incapacitation considerations (see §25.1523-1).

I am looking for any incident reports of events, in which the second pilot (irrespecive of rank) on the flight deck has corrected a (fatal) mistake made by the other pilot or discovered a failure of some sort which was not discovered by the other pilot, and thus averted an accident. So not the daily flight in which everything is normal, but those in which something went wrong which was then corrected by the second pilot.

Mostly, only events in which something goes wrong and which turn out as severe incidents or accidents are reported as such. These events are thoroughly investigated to learn from these events and make aviation safer. I am, on the other hand, interested in the other 99,99..% of events. Those events that are rarely reported, because everything turned out well in the end, "almost-accidents" that were prevented by the second pilot on board.

Besides the obvious pilot incapacitation events, can anyone recall any specific events / flights and direct me to the respective (official or non-official) report, i.e. by the U.S. NTSB, the French BEA, the German LBA, the British & Australian CAA, …?


texts: What are the properties of the wing (airfoil symmetry, angle of incidence) of an aerobatic aircraft?

texts: On an aerobatic aircraft, such as an Sbach342, what type of airfoil does it have and what angle of incidence does it have in relation to the fuselage?


texts: Why is the IRST not centered on the Eurofighter Typhoon?

texts:
Following links included in this answer, I noticed the IRST is located on the left side of the Eurofighter Typhoon. It seems that this asymmetrical location is common (Dassault Rafale, MIG 29,...).

Why is the location of this device chosen so that on side seems privileged? I see no reason to prefer one side over the other, there should be the same chance for a target to be located on one side or on the other.


texts: Advances in rivet technology for Aircraft?

texts: What advances have there been in the manufacture of rivets which are used for joining for aircraft and rivet technology and materials used?


texts: How should I interpret the Douglas DC-4 approach climb performance chart?

texts:
Can someone explain what "C = .04 Vso2" means as the "denotes required rate of climb?". I assumed the point at 6500 ft altitude and 60,000lbs landing weight will mean that the required rate of climb is within the limitations but after calculating this to an approach climb gradient, the answer does not require the limitation of a minimum approach climb gradient of 2.7%.

So the main question is: What does the dotted line mean and what has the C = .04 Vso2 has to do with it?


texts: What is the reason for allowing pilots to take Pilot Aptitude Battery Test (PABT) only once?

texts: Indian Airforce conducts a test called PABT (Pilot Aptitude Battery Test), for anyone who wishes to be a pilot. This test can be taken only once, and once you fail it, you can never appear again (which inherently disqualifies you from being a pilot in the Indian Armed Forces). Why is such a test so important, and how does failing in it reflect on your piloting skills?


texts: Is it even remotely feasible to turnback a single engine aircraft with an engine failure?

texts:
Note before reading further that I'm asking this question purely on theoretical grounds, though you are more than welcome to talk about practical aspects as well.

Now, my question. It's common knowledge amongst many pilots that turnbacks are one of the least safe methods of attempting to survive an engine failure in a single engine aircraft. However, is it actually possible at all to turnback an aircraft to return to the airport perimeter or the runway? How much of it is simply pilot error in executing a possible manoeuvre, as opposed to pilots thinking that they can pull something off that is just impossible, no matter what?

For the purposes of this question, we shall assume the following:

there is only one runway, so a reciprocal turn is required (we shall assume 210 degrees)
the aircraft has a flaps up stall speed at MTOW of 75 knots
the aircraft has a best glide ratio of 1:12 at 100 knots

Alternatively, if you have any other information that is more akin to a real aircraft, you can use that in lieu of this information.

Sources or an explanation as to why this it is or isn't impossible would be appreciated in your answers.


texts: How will radar systems be used in FAA's NextGen ATC plans?

texts:
Based on the reading I've been doing of FAA's Next Generation Air Traffic Control (NextGen) plans, I've been wondering if and how radar systems will continue to be used for ATC as NextGen rolls out?

Questions include:

Is it correct to assert that radar coverage will effectively become a less precise, backup only, data feed? I am suggesting this because my understanding (which could easily be incorrect) is that ADS-B will mandated for most (everyone?) and so aircraft will be actively reporting their precise position without the need for a radar track.
Will existing radar coverage eventually be phased out?  Seems unlikely due to airspace security issues alone. But are there any other reasons to keep radar coverage?


texts: Is an approval required to fly from the right seat?

texts:
I asked this as a comment in this question, but I thought it was worth asking properly to preserve it for future Aviation.SE generations.

Is there any sort of permission required to fly from the right seat of an aircraft? If I've done all of my training on the left side of a C172 is there anything stopping me from deciding one day to stick a passenger in there and fly with my right hand?

I acknowledge that for experienced pilots there shouldn't really be a safety risk in doing this, but many light aircraft displays/instrumentation are designed for the pilot being in the left seat.


texts:
I have a picture of Air Force One I took fairly up close several years ago.

Unfortunately, I don't remember if that was on arrival or departure.

Is there anything visible in the airplane's configuration (flaps, angle of gear?) that would indicate if this is arrival or departure?


texts: Do helicopters have trim? How does it work?

texts:
I recall having read somewhere that “helicopter in forward flight behaves just like a badly trimmed airplane”. So I'd like to ask:

Do helicopters have trim?
If so, how does it work?
And is the helicopter stable when properly trimmed?


texts: Would a triplane be way more efficient if the wings intersected at the tips to create one wing tip vortex instead of 3?

texts:
Would a triplane be way more efficient if the wing tips were joined at the tips to create one wing tip vortex instead of 3, at RE 200-600k? At that low of a speed, I assume interference and form drag are minimal.

I understand biplanes and triplanes are less efficient than a monoplane due to wing root interference drag and wing tip vortices.

Yet..... I understand boeing/NASA are experimenting with a biplane/braced wing airliner configuration, which would have extra induced/inference drag.

So, to reduce those nasty wingtip vortices, couldn't one just intersect the tips?

I'm thinking, the top wing would have anhedral, a straight middle wing, and bottom wing with dihedral, meeting at the tips.


texts: Why does the UH-1 Huey have a hump at the rear of the cabin?

texts:
Why does the Huey have this weird hump as shown in the picture? For some system? Why not remove it?

https://www.helis.com/h2/uh-1h_seats.jpg


texts: Is an aircraft capable of flying at 900 km/h at 8000 metres above ground?

texts:
There was a question in my maths textbook and I wondered if it was actually possible.

P.S. 8,000 metres is about 26,000 feet.


texts: When leaving ground effect, why is there a nose-up change in moment?

texts:
The Airplane Flight Handbook states:

  The aircraft leaving ground effect will

  Require an increase in AOA to maintain the same CL
  Experience an increase in induced drag and thrust required
  Experience a decrease in stability and a nose-up change in moment
  Experience a reduction in static source pressure and increase in indicated airspeed

I'm having a hard time understanding the number 3 here.

What's the aerodynamic reason for the nose-up change in moment after leaving the ground effect?

Is it because the downwash from the wings increases as the aircraft leaves the ground effect, thus placing a greater downward pressure on the horizontal stabilizer?


texts: What are the eyesight requirements for LPPL/LAPL in the UK?

texts:
I am a UK resident, and I am interested in learning to fly. Unfortunately my eyesight is not great, and I don't believe I meet the requirements for a PPL.

From my research, it seems the medical requirements of the LPPL and LAPL are a lot lower, and I may qualify for these, but I'm a little unsure of the requirements in terms of eye sight requirements.

I currently wear contact lenses, with corrective strength of -9.5 and -10.

Does anyone know what the requirements are under LPPL/LAPL in order to qualify?


texts: What weapons do A-10 Warthogs typically carry?

texts: What is the A-10 Warthog's typical operational load out? Seeing as it is built a tank buster, does it actually carry anti-tank weapons, and what situations would they be used e.g would they (A-10's) ever use an AGM or ASM on a tank?


texts: How does the severity of barotrauma vary with rate of descent?

texts:
This answer proclaims one way to mitigate barotrauma:

reduce the rates of your descents, which will give your ears a chance to equalize. ATC, however, expects you to descend at between 500 and 1,500FPM, unless you are given "AT PILOTS DISCRETION."

Correct me if I don't write this mathematically correctly, but what's $\dfrac{d(barotrauma)}{d(FPM)}$: the first derivative of barotrauma with respect to FPM?
E.g. how much less painful is 500 compared to 1 500 FPM?


texts: How are wingtips attached to the aerofoil while maintaining structural rigidity?

texts: I've been trying to research various methods on the joints between the winglet and the wingtip out of interest. I'm aware that the airfoil is attached to the underbody of the fuselage by means of a butt joint, but with companies like Aviation Partner who offer options such as BBJ's, how are these winglets attached?


texts: Why are piston engines so unreliable in airliners?

texts:
Before the first jetliners appeared, all airliners used piston (reciprocating) engines, which were astoundingly prone to failing in flight, to the point where an inflight engine failure was an everyday, expected occurrence.  To quote Wikipedia:

  Engine failures were considered fairly routine events on piston-engined airliners in the 1940s, so the crew elected to continue the flight to Dallas, and Captain Claude announced to the passengers that they would switch to another airplane upon arrival.

In contrast, in-flight failures of modern turbofan engines are so rare that most pilots will go their entire careers without ever encountering one.  Even in the 1950s, jets were already more reliable than piston engines, which was one of the reasons they quickly seized centre stage for long-distance operations.  For low-altitude short-haul flights, where jets are inefficient compared to propellers, airliners still switched away from piston engines, moving to turboprops en masse despite piston engines having better fuel efficiency than turboprops.  All of this is despite turbine engines placing far greater thermal and mechanical stresses on their components than any piston engine.

Nowadays, piston engines are generally used only on very small general-aviation airplanes... and are no less reliable than the turboprops and jets on larger aircraft.

What is it about piston engines that makes them so unreliable on large aircraft, yet extremely reliable on small aircraft?


texts: Why would a Blue Angels pilot leave their gear down?

texts:
In a recent Blue Angels airshow, one of the pilots had their landing gear down during the first 5 minutes of the show. What possible reasons would justify leaving the aircraft in this state?

No picture available.


texts: Helicopter crop duster minimum altitude over homes (not field)

texts:
I am asking specifically regarding helicopter making approach to  field over home adjacent to field being treated.

In this example:
Helicopter repeatedly passed over my single story rooftop at easily  15-30 meters above rooftop, or less.
Spray contacting me at same time.

Is this allowed, especially when there appear to be 2-3 other possible alternative approaches that would not require flying over the rooftop of a single family dwelling at such a low altitude?!


texts: How many wing attachment nuts are there on a DC-3/C-47? I once participated in putting one together and is now writing about it, but cannot remember how many nuts there are, only that it took forever to line them all up.


texts: Is this ferry flight route possible for a B737-800 WL?

texts:
Recently a new aircraft, B737-86X (tail AP-BNA) was delivered to a new airline in Pakistan.

The ferry flight as reported by planespotters is BFI - BGO - KHI but this seems like a large stretch given the performance of the aircraft (range of 3,115 nm); so I am trying to find the exact ferry route taken.

However, flightware only shows the test flight when I search by the tail number.

Is there a way to find out what the actual flight plan was?

To clarify based on comments:

I am aware that additional modifications can be done on ferry flights (since these are not normal passenger flights) - such as adding of additional fuel tanks - however, due to the facilities available at KHI I doubt this was the case.

Further I understand that it may be possible that the plane was flown BFI-BGO-KHI - even without any further modifications (favorable winds, etc); so I am trying to find a way to confirm what was the actual flight plan; or if crew-only 737-8 WL can fly that route without modifications.


texts: How do the compressor stages keep spinning after start in a free turbine?

texts: In a ‘free’ (or uncoupled) turbine engine (specifically the Rolls Royce C20-250), what is spinning the compressor blades (N1) after start? It can’t be N2, because it’s a free turbine. I don’t think they’re freewheeling, because otherwise how would I get bleed air? And I’m pretty sure the combustion chamber is ahead of the N2 stack, so N2 wouldn't have its own compressor wheel and if it did, I wouldn't have clean bleed air.


texts: How can I see all commercial destinations to a country from a particular airport?

texts: I live in Las Vegas, which obviously has a large airport with a broad array of international flights. Is there a quick way for me to see all the non-stop commercial flights that are available to Mexico? I don't need to necessarily know the airline, just which cities are available for non-stops from Las Vegas.


texts: In wind tunnel testing "same Mach number" is not "same airspeed"?

texts:
Wikipedia:
"Mach number: the ratio of the airspeed to the speed of sound should be identical for the scaled model and the actual object (having identical Mach number in a wind tunnel and around the actual object is -not- equal to having identical airspeeds)"
source
Why identical Mach number in a wind tunnel and around the actual object is -not- equal to having identical airspeeds?
If plane fly at 0.5 Mach(617km/h) that mean airflow speed for test model must also be 617km/h ,to has same compresibility effects?
Isnt it?


texts: What factors are involved in determining the spanwise pitching moment distribution?

texts:
Assuming that I have a known $C_M$ (pitching moment coefficient), $C_L^{'}$ (lift per unit span) and wing geometry, how would I determine the spanwise pitching moment distribution?

Which point on the section of the aerofoil would I take moments about?

Would the weight of a propulsive produce a pitching moment and hence affect the pitching moment distribution?


texts: Are there cases of aircraft moved off runway by pushing them with vehicles?

texts:
And now something completely different for Summer holidays. Arthur Hailey was a RAF pilot who wrote Airport, a novel which later was adapted as a movie by George Seaton. The action is said taking place at Chicago Lincoln International, a fictitious place comparable to O'Hare, while Illinois is under a severe snow storm.

The suspense revolves around a Boeing 707 stuck at an exit, blocking a long runway. Another 707 needs the runway for an emergency landing.

Source: YT

Bakersfeld, the airport manager, wants to push the stuck plane off the runway with snowplows. Joe Patroni, chief mechanics for TWA wants to save the airplane by moving it by its own power.

Clocks are ticking... airports are closing... fuel is starving... Patroni's cigar has gone out.
Bakersfeld releases the snowplows!

What is today's way to:

Prevent a commercial aircraft to be stuck near the runway.
To quickly remove an airplane from the runway should that be necessary.

Is there actual cases of aircraft removed à la Bakersfeld?


texts:
Why are offset lead-in arcs used?

Image source: Google Earth, showing offset lead-in arcs.

There is little literature on the subject matter. I did research it a while back but I lost the PDF's, and videos. Research was inconclusive.

But I did learn that they guide only one aircraft type—selected radius can only accommodate a single wheelbase, radii vary. Initially I thought long airliners (A346, B773, and so on). But watching videos from observation decks in airports, even a 777-300 doesn't follow it. Whether taxiing in or pushing out, it wasn't even close to the line.

So if only one wheelbase can benefit, and it is not long airliners, why use it?

Image source: Google Earth, showing non-offset lead-in arcs.

Image source: Google Earth, showing straight lead-in lines.

All images from KJFK.


texts:
I bought these from a metal scrapper and paid about $30.00 total figuring they're worth more than that in cool factor. Problem is they aren't nearly as cool if I can't figure out what engine (and hopefully aircraft) they come from. All I know is the compressor blade is titanium and the turbine blade has a high nickel content. So here I am hoping someone has an idea.

Also what might cause the wear patterns at the tip of the turbine blade? I appears like it may be cracked and then repaired. I cant imagine they would repair damage that extensive.

I cant find any pitting on the edges of either blade, leading me to believe neither blade was ever used, is my thinking correct?

Turbine blade

source album

Markings:
Suction side

1475M85  (Possible 1475M35)
BF P01 C (could potentially be a G at the end)

Pressure side

FDW157B9

TE

1435P02
59669 (hard to see, could be something else)
G12P

Compressor blade

source album

Markings
Foot:

B778503 FC
MOJR


texts: What is the Mach Never Exceed number for a C-130J Hercules under ISA conditions (approximations are welcomed!)

texts:
I am looking for the Mach Never Exceed number for a C-130J Hercules so that I can create an approximate 1g envelope.
Does anyone have any idea what this can be? I am trying to find the value for similar aircrafts so that I can make an educated approximation but I am having no such luck. Perhaps someone with more experience can provide me with an educated estimation.
Thanks!


texts:
I have an International Priority parcel being shipped by FedEx from Zurich, Switzerland to Perth, Australia.
Currently the parcel is located in Singapore, I presume with FedEx at Changi Airport.  It is scheduled to be delivered by 1700 on 09 October (GMT+8).  The parcel (tracking #771679606750) is showing in tracking at Singapore since 0636 05 October (GMT+8).
From what I can see on FlightAware and Flightradar24 there are no scheduled FedEx Express flights from Changi to Australia, at least up to Wednesday 07 October as I can't see past that date.
This raises the question given the parcel is scheduled to be delivered by 09 October (GMT+8), if FedEx uses other airlines for parcels, or for International Priority parcels?
Note that Sydney is the usual point of entry for FedEx, and Perth is a day's flight from Sydney, and another day for distribution at Perth.


texts: Looking for an API that can provide the amount of flights bought from point a to point b on daily basis

texts:
I would like to know if any of you could help me finding an API source to gather information on daily bookings/sales from point A to point B, i.e. how many seats were sold landing or finishing a trip in Dallas airport and where was the beginning of the trip (point of departure).

I will truly appreciate any help, data does not need to be real time, a day or two, even a week delay would be fine. I am trying to correlate demand with other multiple variables but need to get the data from the demand side.

Thanks in advance for your comments

Ben


texts: Are most/all flights affected by a noticeable amount of turbulence?

texts:
How common is turbulence that is severe enough to feel uncomfortable? I don't mean a little shaking here and there, but a drop that lasts a second or two.

Last 2 flights I was on (Paris to Singapore, and Singapore to Sydney) had more than one big drop of turbulence, to the point where passengers screamed.

Is this common? I know it is relatively safe, but feel uneasy about flying again as it was uncomfortable and scary!


texts: What is the current state of research on Autonomous Air Traffic Control?

texts:
I am trying to get informed about Autonomous Air Traffic Control. Communication is crucial in this field. I am aware that different possibilities exist to realize it, for example:

an ad-hoc network for aircraft-to-aircraft communication
an infrastructure-based communication system

of course infrastructure-based communication systems (meaning a geostationary satellite) include a high propagation delay.

Anyways, I am thinking about a good solution for this problem and am currently looking for research papers in this field. I figured, maybe someone here knows some good sources already?


texts: What is a gold seal flight instructor and how does it differ from a usual flight instructor? Does it offer any additional privileges or prestige?


texts: What is the definition of visibility as seen in aviation weather reports?

texts:
If you look at the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) page for Washington D.C., Reagan National Airport (KDCA), it shows hourly weather observations proceeding back from present through time.

I notice that there has been 10.00 miles visibility all the way back to 17 August, where for one hour there was only 7 miles visibility. During these hours of 10 mi visibility, there are multiple conditions of cloud cover, ranging from Light Clouds, to Overcast, to Light Rain.

What is "visibility" when added to a weather report broadcast from an airport? It seems that if I am in the middle of Light Rains, well then my visibility cannot be "10 miles".


texts:
While conducting a structural analysis FEA for an aircraft wing, I had to import the CFD pressures acting on the wing, lets say at an A.o.A = 10 deg, at 80 m/s and at  sea level, and say the atmospheric pressure is 1 atm. Should the imported pressures from CFD analysis (on the top surface and bottom surface of the wing) be the absolute static pressures or the net pressures? (Assuming the wing surfaces have no slip condition).
If I use the absolute pressures, then the top surface would be experiencing a positive pressure meaning that the pressure is acting onto the top surface (causing it to shrink), and if I use net pressure then that would be negative meaning that the pressure is acting out of the top surface (causing it to expand).
Which one is true? I think that absolute pressures should be used because if, for example, we want to know the structural behavior of the wing top/bottom surface under 1 atm only (assuming wing is symmetric and at an A.o.A = 0 deg), then the net pressures would be zero and we wouldn't have any forces acting on the top or bottom surface of the wing.
Also, does the wing's top surface, in reality when it is flying, deform out (i.e. expands) or deforms in (i.e. shrink)? I think since the absolute pressure is still positive so it must deform in, but some sources say that it instead deforms out. (Assume a static structural condition). A such source I am attaching in the picture.


texts: Can a helicopter be "stalled" by pulling too hard?

texts:
In the PC game Arma 3, there is a helicopter-race game mode, in which the player tries to manipulate the helicopter to pass a serious of hoops as fast as possible in an AH-6.

In the game, if the player banks the helicopter then make a sudden and hard pull on the cyclic to make a turn while max collective is applied, the low rpm warning will sound, followed by a loss of power and a few seconds later loss of attitude control. The aircraft can be recovered by:

Lowering the collective
Releasing stick pressure
Leveling the aircraft

After which the rpm will increase back to normal again.

My guess explanation is as follows:

When max collective is applied, the blades are working hard by cutting air at a large angle of attack
When the aircraft is banked and aft cyclic is applied, the airflow relative to the aircraft is like when it is in a very high rate descend
The critical angle of attack is exceed on the rotor blades, they stall and cease to produce lift
Due to the greatly increased drag, the main rotor is unable to keep rpm up with its power, therefore rpm decreases
As rpm decreases, less lift is produced and the stall worsens.
By reducing collective, the drag of the blades is reduced, and rotor power is enough to keep rpm at normal range again.

Is my explanation correct? Can this happen in real life?


texts: Formula for calculating turn indicator (deviation from coordination)

texts:
being more a professional programmer and less prof pilot, I am building a small
Android EFIS and I'm able to calculate quaternions, yaw, pitch, roll, TAS, acceleration values etc. I am stuck calculating the deviation from a coordinated curve indicator, usually the small ball in the turn indicator. Could someone please point me to a formula? I'm finding only formulas about calculating the necessary bank angle or radius from speed.
Thanks in advance and best regards
hk


texts:
I recently drove by what seemed like an unusually tall structure and used Google Maps satellite view, its distance measurement tool, and basic trigonometry to calculate that this building (some kind of grain silo at a poultry processing plant) was 175 feet tall above the ground.

But, it does not show up on the sectional map.  Other nearby structures, mostly 300-350 feet or greater, do indeed show on the map.

At what minimum height above terrain does a vertical structure need to be indicated on a sectional map?


texts: Can I fly a practice LNAV approach with an iPad?

texts: I'm doing training for an instrument rating, and I'm thinking I'd like to do some solo VFR cross country flying and do some practice instrument approaches.  The C152 I'll be flying doesn't have a GPS installed, but I'll have ForeFlight on my iPad.  Since I'm VFR, could I request a practice LNAV approach from ATC and use my iPad to navigate the approach?  I realize this isn't quite as good as doing hood training in an aircraft with GPS, but I think it will be of some use to me in my training.


texts:
Why is KOAK's alternate minimum higher than standard?

According to TERPS (FAA Order 8260.3C) section 3-4, alternate minimum for PA is the higher of PA minimum or standard alternate minimum(600'-2).
KOAK ILS 12 minimum is 200'-1/2. Standard alternate minimum is higher than that PA minimum. Thus, alternate minimum should be 600'-2(standard). But actually, alternate minimum for KOAK ILS 12 is 1400'-3(for CAT D aircraft).

I'd like to know how alternate minimum to be determined.


texts: Can a commercial cargo aircraft be converted into a commercial passenger aircraft, and vice versa?

texts:
Just saw a video in a news, a military cargo plane carrying people stranded in some country. The seats were like in a commercial airliner. This led me to ask the question.

Would it be possible to see some examples where it was done, along with the procedure?


texts:
I'm a little bit confused by representation of negative number in ARINC-429.
Let's consider the following example:

Significant bits is equal to 7 (it does not count sign bit),

Resolution is equal to 1,

DATA section has to represent -1 value.
Initially I thought that DATA section is represented as follows:
1 1 1 | 1 1 1 1 | 1 0 0 0 | 0 0 0 0 | 0 0 0 0

But I'm confused by sensor documentation. There sign bit is not in DATA section and I started to think that maybe bits 29-11 should look like that:
1 0 0 | 0 0 0 0 | 1 0 0 0 | 0 0 0 0 | 0 0 0 0

Which way of thinking is correct?


texts: Is a slip an intentional consequence of a cross-control?

texts:
In flight training, you're always told not to cross-control, (for example, rolling right aileron, and stepping on the left rudder), but it seems to me that is exactly what a slip is doing.

Is it that a slip is intentional, and a cross-controlled situation is typically unintentional?


texts: Does a GPS OBS selector use magnetic or true courses?

texts: Under GPS navigation, when we are using the OBS to tune courses. Are these courses magnetic or true?


texts: What is the difference between Hobbs Time and Tach Time?

texts:
Over in this answer there's a description of Hobbs Time versus Tach Time, and how the Hobbs counts hours while the tach time is equivalent to "hours at cruise RPM".

How do these two "clocks" work, and what do these numbers mean in practical terms for flying and maintaining an aircraft?


texts: what type of sensors does the Boeing 737 MAX use for MCAS?

texts: I can imagine there are several different ways to measure angle of attack (accelerometers, relative pressure measurements between pitot tubes, etc), but I'm curious which sensors the 737 MAX uses for its MCAS system since it's been in the news recently.


texts: Does every control surface need to have a counterweight?

texts:
Is it not a good idea to balance all control surfaces, no matter what they weigh?

I am building a small plane, with small control surfaces. There are many of the same type of plane flying. Most have no type of counterweight "balance" on the elevator, or rudder. I am told that is because the surfaces are small and light.


texts: On an ADS-B In display, do the pilots see the squawk code or call sign for other aircraft?

texts: If I understand correctly, with a ADS-B In equipment or TCAS equipment on board, the pilots could see the surrounding traffic with its assigned squawk code like "4653", is that right? But could the pilots know the aircraft identification like "UA858"?


texts: Why was a CFM56 conversion never offered for the short-body DC-8s?

texts:
A major part of why the DC-8 hung on well into the 21st century (albeit almost entirely in cargo service) was the late-1970s/1980s conversion of 110 DC-8-60s (out of a total of 262) into DC-8-70s; the main (or, for the DC-8-6/72 and DC-8-6/73, the only) change was the replacement of the DC-8-60's old, loud, thirsty Pratt & Whitney JT3D low-bypass turbofans, and the nacelles thereof, with new, [relatively] quiet, efficient General Electric/SNECMA CFM56 high-bypass turbofans (and the nacelles thereof).1 2
Only the DC-8-60 was eligible, though; the short-bodied versions of the DC-8 (the DC-8-10/20/30/40/50), which formed a slight majority of all DC-8s ever produced (2943 out of a total of 556, as compared to the 262 DC-8-60s)5 needed not apply, even though they would have benefitted just as much from the reengine as the DC-8-60 did, and the process would have been mostly the same (in fact, the DC-8-61 was merely a straight fuselage stretch of the last short-bodied version, the DC-8-55, and, yet, the former version got [the opportunity for]6 a reengine, while the latter did not).
Why did the short-bodied versions of the DC-8 never get offered the CFM56 upgrade that was extended to the DC-8-60?

1: Thus continuing a long tradition of up-engining older-model DC-8s to newer-version standard, although the DC-8-70 was the only DC-8 version for which this was the only possible way of getting one (without any being built new).
2: The April 1979 decision to reengine DC-8-60s with the CFM56, incidentally, saved said engine from extinction, allowing it (in multiple later versions) to later see service on the 737-300-through-900, A320ceo, and A340-200/300.
3: Over half of these were of the latest and greatest short-bodied DC-8, the DC-8-50 (142 built new, plus a total of 20 converted to DC-8-50 standard from DC-8-10s [12 aircraft], -30s [5], and -40s [3]); there were also 52 DC-8-30s (not including the five converted into DC-8-50s), and smaller numbers of -20s and -40s (but not -10s, all of which [except for two which crashed first] were converted to DC-8-20 or DC-8-50 standard).4
4: I am aware that many of the short-bodied DC-8s had either crashed or been retired by the time the 1980s rolled around; however, this was also true of many of the almost-as-old DC-8-60s.
5: Numbers from here (Wikipedia, unusually for it, has had some major inaccuracies regarding the production and conversion numbers for the short-bodied versions of the DC-8, especially the DC-8-50).
6: Surprisingly, many DC-8-60 owners and operators did not take the opportunity to upgrade their aircraft.  Out of 262 DC-8-60s produced, only 110 were reengined into DC-8-70s; some of the remaining 152 DC-8-60s were presumably aircraft that had already crashed or been retired by the time the reengine programme came around, but, even of the DC-8-60s that were still around, many went unupgraded.


texts:
The CH-46 and the CH-47 Chinook are very similar-looking aircraft and seem to serve similar purposes - only though for different branches of the U.S. military.

What are the differences between the CH-46 and the CH-47?
Why does the military run both instead of settling on one?


texts: Can an airplane on an SVFR clearance land when visibility is less than 1 mile?

texts: Let's say I'm on an SVFR clearance and the flight and reported ground visibility deteriorates less than 1 mile, what happens?


texts: Is it permitted to deviate from yellow lines, during taxi?

texts: During taxi procedures, the pilot should follow the yellow lines, to avoid a collision with any obstacle or even with another aircraft. Is the any situation, which the pilot can deviate from the yellow line at their own discretion?


texts:
After doing some research, I found two apparently conflicting articles. The first, dated Sep. 23, 1848, describes John Stringfellow as marching through the air in a tent. The second, published about 20 years later (July 10, 1868) quotes Stringfellow as declaring that the world still waited to see him flying.
Question: Did John Stringfellow ever build an aeroplane, powered by a steam engine, that really flew? Does it exist written contemporary evidence (letters, articles, patents, etc.) proving that this inventor designed, built and flew a plane of any kind (manned or just a model)?
1848-09-23, Scientific American, September 23, 1848, col. 3, p. 4.

An Air Navigator.
A series of experiments have lately been made beneath an immense tent
in Cremorne Gardens, London, by a Mr. Stringfellow — a fine name for
suspension. The inventor marches through the air by a machine which
sustains and propels itself through the cicumambient fluid. The
machine excited considerable attention and surprised all the
spectators by its wonderful performance. The next expedition that is
fitted out by the British government to explore the Niger and the
country through which it winds its sluggish and pestilential way,
should employ this Mr. Stringfellow with a number of his machines to
make a flying exploration, untramelled with their heels in mud or
water.

1868-07-10, "Aerial Navigation", English Mechanic and Mirror of Science, July 10, 1868, col. 3, p. 341.

Aerial Navigation ...
Mr. Stringfellow, one of the exhibitors at the Crystal Palace,
enthusiastically declared that the world should yet see that he could
fly with his own machine, and this opinion seemed to be universally
held. ...


texts: Could aircraft already do a safe auto-takeoff with todays equipment?

texts:
If a plane can already autoland and stay aligned while roll-out by itself, on a CAT-3 ILS-Approach, I asked why there is no auto-takeoff-function on todays autopilots.

Because it should be technically possible and much safer than a hand flown takeoff.

For the technic:
When on the runway, the pilot presses an auto-take-off button. The plane stays aligned by following a normal CAT-3 Localizer. Takeoff-Thrust is made with autothrottle. At Vr, the plane rotates by itself, smoothly,and activates VNAV and LNAV and follows the SID. It is also possible to implement a live wind sensor to dynamically update V-Speeds.
For safety:
In case of an emergency during take-off, a computer take-off would be more safer. The plane knows the speed and runway length. So in case of an emergency, it knows if it's below V1 and also if the available runway length is sufficient for a safe rejected take-off. A computer always has a lower reaction time than humans and they can response faster. A computer can immediately decide wether to take off or reject based on lots of live data. A (rejected) take-off performed by a computer should be times safer.

So, why has an autotake-off-function not been developed yet? And what arguments would speak against an auto-take-off function?

--
There is not an answer to my question here: On modern commercial airliners, how much of the flight could be fully taken care of by the auto pilot? as stated below. I want to know what reasons, if there are any, speak against auto-take-off.


texts: Am I required to report entering the hold in lieu, persuant to the IFR mandatory reporting points?

texts:
You are cleared for the RNAV (GPS)-A approach at 0S9.

You are cleared direct JIGEB then at or above 3200 to YAYUB then cleared RNAV GPS A.  You are not asked to report anything.  Upon arriving at YAYUB you perform a parallel entry to the hold reverse course and the proceed inbound.

If this was a procedure turn I am not required to report the procedure turn unless ATC requests it.  However, this is a hold in lieu of a procedure turn.  Am I required to report entering the hold persuant to the IFR mandatory reporting points?


texts: What FAA regulations govern a US International Airport name change, such as McCarran International to Harry Reed International?

texts: What FAA regulations govern a US International Airport name change, such as McCarran International to Harry Reed International or Las Vegas International Airport?  Can the citizenry petition the FAA for or against such a change?


texts: Are airlines responsible for Airport security or Airports concerned or third-parties on terminal-side?

texts:
In Indian Airports, all sort of terminal-side security is done by CISF . They do all the frisking and baggage screening etc. I am concerned more for the terminal-side security rather than airside where it comes under the airlines domain.

Is it similar in the rest of the world or are airlines responsible? Some notable incidents I recall are the recent Brussels Airport attack, and the 2015 Sabiha Gökçen Airport bombing. I would suspect most airports now are under some sort of integrated command and control center modeled on the American system after 9/11 rather than have disparate silo-based security which may have holes that both terrorists and criminals may be able to get through.

I am talking from port of departure, where the procedure is, show tickets, passport at the main gate, go through security check, get boarding pass and board the plane.

Similarly, while de-planing, you go through customs and immigration, security check, baggage inspection etc.

At both places, security check is apparently done. My question is who is responsible, either the Airport Operator or the Government or a multitude of authorities ?

I am trying to be as generic as possible so as to know if there are variances or are most Airports following some set conventions ?
There have been many articles about TSA high-handedness but guess that's to be expected.


texts:
All glass cockpits seem to have the same basic setup for the primary instruments. Altitude tape on the right, air speed tape on the left, turn coordinator on top and an artificial horizon in the background. I can't find any good information on how the glass cockpit came to be and more specifically, how this layout was developed and adopted. I'm curious about:

Who developed the first glass cockpits?
Which planes first used these glass cockpits?
How was the current layout developed, were other layouts in use beforehand?
Was there any resistance or difficulty in getting these systems adopted amongst pilots or their companies?


texts: Can variable incidence wings replace ailerons?

texts:
If a wing can change its incidence angle, can aileron be omitted in the design?

Since aileron are used to increase lift and decrease it. so is the incidence angle.

How would the two solutions compare?


texts: Is this paragraph about the dihedral effect in the FAA's Glider Flying Handbook correct?

texts:
I've been reading the FAA's Glider Flying Handbook, 2013 (FAA-H-8083-13A). In chapter 3 ("Aerodynamics of Flight"), the book is discussing stability. On page 3-12, it states:

  Dihedral is the upward angle of the wings from a horizontal (front/rear view) axis of the plane. As a glider flies along and encounters turbulence, the dihedral provides positive lateral stability by providing more lift for the lower wing and reducing the lift on the raised wing. As one wing lowers, it becomes closer to perpendicular to the surface and level. Because it is closer to level and perpendicular to the weight force, the lift produced directly opposes the force of weight. This must be instantly compared to the higher and now more canted wing referenced to the force of weight. The higher wing's lift relative to the force of weight is now less because of the vector angle. This imbalance of lift causes the lower wing to rise as the higher descends until lift equalizes, resulting in level flight.

That doesn't sound right to me.

This paragraph says that there's more lift on the lowered wing and less lift on the raised wing. That's not true, is it? The amount of lift only depends on a wing's airspeed and angle of attack, not on the wing's bank angle.

The paragraph then explains that the lowered wing produces more upward lift than the raised wing. I think this is true, but it's not relevant, because upward lift isn't the only lift which contributes to rolling moment. Rolling moment depends on the total lift (and the direction of the lift).

All in all, I think that dihedral can't produce a stabilizing rolling moment in the way that the book says that it does. Any stabilizing effect must come from a difference in airspeed or angle of attack between the two wings.

Is the book's description of dihedral correct?


texts:
While Emirates was showing off its triple seven's ability to provide crystal-clear viewing from virtual windows, it mentioned: "that could be a step to windowless aircraft", and I felt like it meant to evolve into something better.
So, my question is, what would be better in general, a windowless aircraft or one with windows? Is there any improvement that comes with a windowless Airbus for example?


texts: How much oxygen is put in say a 180-seater A319 or A320 aircraft?

texts:
I read the answer in How much oxygen do commercial airliners carry? but it doesn't go into any details about two things:

How much oxygen is carried? I do imagine it would be quite a bit.

How much weight does it have? I am imagining that it probably would be liquid oxygen as that it would be much easier to carry, more compressible, fill everything better than in the gaseous state. I have been reading about liquid oxygen in different contexts hence thought it would be good to ask.


texts:
I am very interested in the 737 combi models and want to learn more about how they worked in practice. For the 737 Combi, How did changing the proportions of the passenger vs cargo areas work?

I have read that regulations require passenger areas to be maintained
at higher pressures than cargo areas in order to prevent potential
fumes from reaching the passengers- is that true? If so, how does
that work in terms of the air pack design and other aspects of the cabin air design?
Could operators change
back and forth the proportion of floorspace that they dedicated to
cargo vs passengers, or was it semi-permanently fixed? If it could be
changed in normal operations, about how long did it take or how many
man hours?
Could the bulkhead between the passenger and cargo areas
be located at any point inside the aircraft ("infinitely variable
bulkhead location" you might say) or were there a certain number of
fixed points that the bulkhead could be positioned?
For 737 combis
operated in a 100% passenger configuration, what did the cabin look
like next to the door? Was the cargo door basically fully finished as
though it was any other part of the cabin, or was it more industrial
looking/louder/colder?


texts: How do fuel tanks prevent free surface effect?

texts:
Free Surface Effect is a fancy term that refers to liquids changing their relative orientation within a container, whenever the container is rotated.
So imagine a large plane banking very steeply, at least 30 degrees. If the fuel tanks in the wing were one giant tank, all the fuel would run down to the end of one wing, and in the other wing the fuel would bunch up near the fuselage. This can change the center of mass and might be dangerous.
How is this prevented? Are their baffles in every fuel tank? Are there many individual tanks instead of one or two large ones? What sort of other designs might address this issue?


texts: How do UAV designers improve visual quality without compromising computational efficiency in mini UAVs?

texts:
I'm designing an Unmanned Aerial Vehicle(UAV) similar in size to the RQ 11B Raven.

This UAV can carry color and infrared cameras to capture outside scenes in real-time. The quality of imagery that these UAVs relay to the operators is directly related to how much of information they can extract from the frames being captured in real-time. So far the captured video looks jittery and not appealing due to vibrations of the platform. I am encountering two issues here

issue of oscillations ; and
low frequency vibrations

Can you guys please suggest how UAV designers have managed to address these 2 issues to improve visual quality without compromising computational efficiency?


texts: Why does MH370 Satellite data disagree with track after take off?

texts:
Can someone please explain the inconsistency in MH370's alleged track after take off?

The satellite handshake offset frequency shows an increase after take off until 16:55 UTC, then a reduction in frequency until 17:07 UTC.

A frequency increase means signal compression, in other words flying west towards INMARSAT.

The problem is after take off at 16:41 UTC MH370 was tracked by radar flying steadily east until reaching BITOD (east of IGARI) when tracking ceased at about the radar horizon. MH370 was never spotted on radar east of the Malay peninsula flying back.

In the preliminary accident report released on May 1st by the Malaysian Government it is shown flying back to Penang. Radar tracking imagery from Butterworth shown to relatives at Beijing on 21 March shows a target flying from Penang at 18:02 UTC across VAMPI and reaching MEKAR at 18:22 UTC.

My question is why the satellite handshake data does not match the claimed track?

The frequency increase implies MH370 flew west after 17:07 UTC, but the radar/transponder  data says it continued east until at least 17:24 UTC.

The other problem is that after 18:25 UTC the satellite data implies MH370 flew away from the satellite.

The satellite movement from take-off until 19:41 UTC was northward from the horizon and INMARSAT's displacement does not seem sufficient to cause the inconsistency.


texts:
For many aircraft root and tip chord is given but the exact location of aerodynamic center and center of gravity is not given. Considering this information;
How can I calculate control free and fixed static margin?


texts: What are the advantages of electrical systems over pneumatic systems?

texts: What are the advantages of using electrical systems as a alternative to pneumatic systems in the Boeing 787-9? Is it a maintenance advantage?


texts: How hot do internal parts of jet engine get?

texts: How hot does a jet engine get? I'm interested in the temperature of the parts, not of the exhaust or combustion. If you took temperature of an engine after a flight across the Pacific Ocean what are temperatures of stationary and movable parts? A car engine block may be 250 degrees Fahrenheit (120°C). I'm thinking of how to modify the basic architecture.


texts: What restrictions are there to building a tower near a private airstrip?

texts: I'm exploring the possibility of putting up a radio tower on a property I own. The problem is that my property is roughly 1,000ft from a private airstrip. The location that I want to put the tower is not within the approach/departure path of the runway and is not under any navigational easements. The height that I'm looking at is roughly 150ft, just high enough to get approximately 20-30ft above the existing trees in the area. My question though is, what are FAA restrictions around building towers near private airports? Is it different from public airports? If so, is it possible to do this at all so close to an existing airport?


texts: Why aren't there any single turbofan airliner?

texts:
A configuration which looks like a DC-10, without engines mounted under the wings. Let's say 737 sized.

Let's forget about redundancy security advantages of twin or quad engines, since they're obvious and not my concern about this particular question.

One single engine is more efficient than two similar engines. Efficiency multiplies, two engines are less efficient, four even worse.

Center of gravity problem doesn't exist since wings can be moved backward.
(of course yaw stability will be corrected inherently)

Modern turbofans family can provide a single stock powerful enough version to fly a 737 class size.

In the event that debris is released from the engine, one canard configuration may be designed, in order to prevent hydraulic failure and loss of control.

To summarize, are there (except redundancy safety concerns) any reason why there are no single turbofan airliners?


texts: Does propeller size affect total drag force of plane?

texts:
Integration of pressure distribution of  each blade  get net force(thrust) which is allways pointing forward.So there is no drag force at  any propeller ,that tells that size of propeller doesnt change total drag force.
So plane with propeller of 1m diameter will has same total drag force as plane with propeller of 2.5m diameter?
(if both planes are same and both propellers have same thrust force,and both propellers are fixed at tail so wash not blow at plane body,causing aditional skin friction and pressure drag)
boat analogy:
Why all speeds boats use small propellers,instead big ones?I allways think reason was big propellers increase boat overall hydrodynamic drag,but when I better think propeller cant cause drag when producing thrust!


texts: How is the JFS manual hand pump operated on an F-16?

texts:
The JFS (Jet Fuel Starter) on an F-16 allows for two attempts to start the engine.

https://www.quora.com/How-do-you-start-the-engine-on-an-F-16-Fighting-Falcon

However, if this fails, there is a manual pump that can be operated:

Where is this pump? Inside the cockpit? Hidden in some hatch outside? How is it operated? How long does it take to build up enough pressure for one more attempt to start the engine?

As a bonus question: Surely the JFS system can be charged with external equipment rather than this hand pump? What is that procedure called?


texts: How to set frequency and distance in ARINC 429?

texts:
How can I set frequency & read distance in ARINC 429?

For example can you give an example to tune a 1105.5 MHz and read 25786 ft.

LABEL | INFORMATION CONTAINED IN LABEL | FORMAT | SPEED
------+--------------------------------+--------+----------
035   | DME Frequency                  | BCD    | Low Speed
202   | DME Distance                   | BNR    | Low Speed


texts: What powers an aircraft prior to the APU being switched on?

texts:
I know that APUs are power plants for non-propulsion related purposes and that they are turned on before takeoff.

What powers an airplane prior to the APU being turned on?


texts: Do Special MEA altitudes and routes in Alaska require WAAS?

texts: Low Enroute IFR charts in Alaska (and maybe elsewhere?) have blue routes and MEAs for GPS equipped aircraft, such as T266, 7000G MEA, below. Is an IFR GPS sufficient to use these, or is WAAS required?


texts: What does "still air" mean when planning alternative airports?

texts:
When planning for a takeoff alternate, according to 14 CFR 121.617

  (1) Aircraft having 2 engines. Not more than one hour from the departure airport at normal cruising speed in still air with one engine inoperative.

What does "still air" mean?

Is it because of the performance tables for Aircraft?

Or just don't take the effect of winds on aircraft range?


texts: What steps have been taken to rule out instrument failure due to blocked static ports or pitot tubes?

texts:
In the case of Aeroperu Flight 603, a fatal crash was caused by duct tape that was accidentally left over some or all of the static ports on the underside of the fuselage after the aircraft was cleaned. As the static ports are critical to the operation of virtually all of those flight instruments that provide aerodynamic data regarding airspeed, altitude and vertical speed to the pilots and to the aircraft's computers, this bit of duct-tape caused the total failure of multiple basic flight instruments.

Another crash was caused for a similar reason: pitot tubes that were blocked by an insect led to flight instrument failure, and later, a tragic crash. This was Birgenair Flight 301.

These accidents happened in the mid-1990s. Today, two decades on, are there better systems in place to ensure that static ports or pitot tubes don't get blocked, causing instrument failure?

Edit 1: In both these flights, the pre takeoff checks missed out on the blocked static ports/pitot tubes. Human error clearly happened at this stage. Question is, have an steps been taken to make the flight instruments proof to this particular human error?


texts: A couple of questions about Aeroflot flight 593

texts:
I recently heard about Aeroflot flight 593 and I know the cause is pilot error or whatever you would like to call that, but I have a couple of question about the aircraft.

First of all, I have never heard of part of the autopilot disconnecting. I have never heard of just the ailerons of the autopilot disconnecting, was this just a feature of the aircraft? Can any new Airbus or any modern day aircraft's autopilot partly disconnect to a system?
Lastly I know the autopilot pitched up and increased thrust to gain altitude but why did it stall, why didn't the autopilot stop pitching the nose up and increasing thrust once it got to high and dangerous?


texts: What causes the reduction in speed across the shockwave?

texts:
Wherever I read about shock waves, it is mentioned that there is a reduction in speed across the shock wave.

Can someone please explain what happens at the molecular level, i.e. the physics of the problem?


texts: Why is luggage required to be loaded in containers?

texts: Luggage is loaded into containers, in Wide Body airliners (as mentioned here). Why is this required to be done? Why don't they simply keep the luggage in the luggage compartment? Why is loading the luggage piece-by-piece time consuming, and at the end, in second photo mentioned there, the luggage is being loaded piece-by-piece. What is that?


texts: Why aren't thin, delta-shaped wings used for fighter aircraft?

texts:
In the past, we used thin, delta-shaped wings (ogival wings) such as those on the Concorde.

These wings can be used up to mach 2.2. Due to high fuel consumption, these wings are no longer used commercially.  However, why can't they be used on fighter aircraft?


texts: What are good books to learn basic aerodynamics in plane design?

texts:
Well, since this stack is in beta, I thought I'd take a wack at asking a book question to see how it fits in this particular community (of if it even fits to begin with).

I'm very curious about how aerodynamics work in plane design (especially wing design), but it's hard for me to ask questions here because I'm lack knowledge of so many of the basics.  So I wondered if I could get a recommendation on a good book to learn the basics of aerodynamics?  Keeping in mind that my understanding of math is limited, so I would need a book that explains the math being used to some extent.

Bear in mind when answering:  This is a Q&A site, so try and have some reasoning behind why your book is the best.  Especially if you could show it has good explanations of the math and, also, the books is good for the somewhat beginner.

Let's see if this works...


texts: How was the 'bump' removed from the Airbus P2F?

texts:
(Sources: airliners.net, YouTube)

How was the 'bump' removed from [the design of] the Airbus P2F?

The A330 Freighter based on the A330-200 features a bump / blister / bulge that raises the nose landing gear to level the cargo deck for easier loading of cargo. A design issue with the passenger A330 is the slanted floor, but it was not a big deal since cargo with feet manages.

  The A330/A340's distinctive nose-down pitch - which is greater than intended in the original design and only emerged when production of the aircraft began in the early 1990s - was a problem that Airbus had addressed on the first version of the A350.

The passenger-to-freighter (P2F) conversion program for both the -200 and -300 lacks this bump. What design change was incorporated into the conversion that fixed the floor level?

The latest information I could find is from October 2009 (8 years ago):

Airbus abandoned the 'bump' modification in favor of a special ground jack to level the deck during loading/unloading.

  Airbus is proposing a piece of external ground-support equipment which would physically lift the aircraft, producing the same effect as the lowered gear in new-build freighters (flightglobal.com).


texts: Are low wings less safe for aerobatics training?

texts: I fly a low wing (CZAW SportCruiser) and am looking for aerobatics training schools, however I can only find schools with high wings available for training. My plane has "no aerobatics" placards inside the cockpit, so apparently I can't use my own plane. Are low-wing aircraft less safe for aerobatics training?


texts: Why weren't the Airbus A330 engines designed with a system to stop their fans?

texts:
Why wasn't the Airbus A330 designed to stop its fans (with some kind of 'handbrake')?

To clarify, I am specifically talking about the aircraft that flew Air Asia flight D7237.

During the flight the aircraft suffered from a fan blade separation event and the the result was that the engine became unbalanced.

This was the result of the incident the plane was able to continue flying for over an hour and a half with the "moderate" vibrations and able to land safely (where the passengers were rewarded with a $20 voucher)

It's my understanding that the engine was immediately shut down, and that the cause of the vibrations was the fanblades freely turning as the plane moved very fast through the air (similar to blowing very hard into a turned off household fan)

But to me, it seems the whole situation could have been avoided if there was simply some kind of "brake" or 'locking' feature that prevented the fanblades from turning freely in the wind.

I feel as though there wouldn't exist another scenario where a plane could possibly experience more severe, prolonged vibrations than a windmilling event, and the windmilling event itself could be prevented if there was simply a way to lock the fanblades from moving freely.

The reason I say A330s in particular is because I am not aware of the features of every other jetliner, although I am aware some propeller engines can feather their blade parallel to the direction of airflow to prevent this.


texts: Which one has a higher success rate between Infrared homing and Radar homing missiles, for air to air combat?

texts:
I know Infrared missiles don't work on long ranges, so I will keep my question limited to short ranges only, in which both missiles can work.

In such short ranges, which guidance system has more chances of success/kill in an air to air combat? Infrared homing or Radar homing?

If one can also lump in Active radar homing and Passive radar homing in his/her answer, that will be an added bonus. Thanks!


texts: Can you turn a large airliner using only rudder input?

texts: Is it possible to turn a large jet like the Boeing 747, Airbus A380 or other airliner using only the rudder, i.e. without using the ailerons on the wings?  Will it take longer to turn to a new heading? I find the tilting when ailerons (wing flaps) are involved is uncomfortable.


texts: How does an airport catch up when it is behind on traffic?

texts:
When airports fall behind traffic for some reason and delays piling up, how do they catch up? If flights need to be cancelled, who decides (and when) - ATC, airport management, or airlines themselves?

As an illustration, here is a snapshot from this page (taken at approx. 2355 UTC 12/23/15):


texts: What is the difference between a Stand and Gate in Airports? How do they differ ?

texts: I have seen Aircrafts having been assigned a Stand and Gate, So wanted to know whether the stand and gate are same physical location of airport or they are different but have link between them.


texts: Why does British Airways fly a short haul flight in a B767?

texts: British Airways operate a flight from Edinburgh airport to Heathrow airport every morning in a 767. Aren't these wide-bodies meant for long haul flights?