texts: Do promotional flight routes have a historical precedent?

texts:
Right now, a Dreamliner is flying a rather strange path over the USA (see below). The plane took off from Boeing Field airport near Seattle, and is 'drawing' a virtual copy of itself on the map of the USA before flying back home.

As flight trackers are a relatively recent phenomenon, I was wondering: is this the first time something like this ever happens, or is this a tradition in aviation which I'm not aware of?

Permalink for the flight.


texts: Why is it the ATC recording of Ethiopian Airlines Flight 302 is not yet available online?

texts: I understand sites like liveatc.net constantly stream the conversation between the ATC and pilots. Why is it that there's no such recording for Ethiopian Airlines Flight 302 yet?


texts: Is "right-of-way" based on aircraft size?

texts:
I was speaking with an ATP-rated pilot the other day, and he said something that sounded odd: basically the bigger aircraft has right of way once airborne.

Can anyone shed some light on this? As far as I understand, ATC coordinates the landing/departing aircraft; at least at my airfield where there was MD80's, B738 and G/A.


texts: A pilot faces a medium-term loss of their medical. What can they expect?

texts:
This closely related question asks about what options a pilot has when facing a permanent loss of medical.

However, not all disqualifying conditions are permanent. Maybe you got an interesting disease known for its 7-month contagious period. Maybe you broke an important, slow healing bone. At any rate, whatever silly thing you did to yourself, you will be flying again, but it will take several months.

As a pilot, what options do you have during this period of your career?  Are you likely to be furloughed?  Assigned alternate duties? I'm interested in answers relating primarily to the United States or Europe.


texts: Velocity induced by a straight vortex filament

texts:
Consider a straight vortex filament as shown below. At each point, there's a point vortex of strength $\it T$. Consider that a point $P$ is there on the outermost circle of flow induced by the vortex about the origin $O$. That is the point $P$ lies in the plane containing the flow induced by the vortex at $O$. So, the only point on the vortex filament that will induce a flow at point $P$ is $O$.
Therefore, the vortex at point $O^{'}$ will not induce any flow at point $P$. Vortex at point $O^{'}$ can only induce flow at those points that are in the plane containing the flow induced by the vortex at $O^{'}$.

So, my question is how Biot-Savart Law is applied for a straight filament vortex? How can the segment $dl$ induce a flow at a point $P$ that is not in the plane? Only the vortex centered at the point of intersection of line and perpendicular from point $P$ to the line can induce the flow at $P$. Please clear my query.


texts: What is the purpose of D-Bag in skydiving parachute?

texts:
Recently I had the opportunity to take a closer look at the skydiving parachute. And I could not explain to my self the reason to use D-Bag and not pack main canopy directly in backpack compartment.
I know that the reserve canopy is packed directly into the backpack. And the sequence for deploying reserve canopy is:

Sky diver pulls release cord, which pulls out the pin that holds the backpack flaps close
Spring loaded drogue parachute jumps out into the airstream
Drogue chute pulls out the main canopy which opens
Sky diver does not flatten him or herself on the ground.

More puzzling is the main canopy assembly. As far as I could understand the main canopy is packed into so called D-Bag. This D-Bag is then inserted into container in the main backpack. Why this intermediate step?
The deployment sequence of main canopy is described here: http://adventure.howstuffworks.com/skydiving4.htm

I wonder what happens to the D-Bag after deployment. Does it hang loose? Does it remain close to the canopy on the upper side?
As far as I understand the drogue chute remains attached on the back side of the canopy and acts as a sort of stabilizer. But what about D-Bag? Does it just flap around?
Why not pack main canopy in separate compartment of backpack directly?


texts: How can the wind speed and direction be calculated from on-board measurements?

texts:
I am currently learning C++ on my own in my spare time. I am writing a little application that will help me while at work.  I have come across a situation where I have some given values, but im not sure of the formula to use in order to render the end answer I am looking for.

Basically, I have the following parameters available to me:

Desired Track
Current Heading
Ground Speed
True Airspeed

I am interested in finding the wind speed and wind direction.

I have googled and googled for hours. Obviously most people use the old aviation E6B. However, that obviously doesn't work for programming. I was wondering if anyone happened to know, or know how I can find that formula.


texts: Do the wheels of taxi-capable helicopters have power?

texts:
There are many big helicopters which seem to taxi just as good as any fixed wing aircraft, for example CH-47.

Do their landing gear wheels have power or they also taxi using thrust like their fixed wing counterparts?

If they do have power, are the taxi controls different from the standard controls?


texts: Are there any helicopters with ejection seats? If so, how is the clearance problem with the rotating blades solved?


texts: What's the purpose of "over G" penalties in Red Bull Air Race?

texts:
This post mentions that if a Red Bull Air Race pilot exceeds 10G acceleration limit for longer than 0.6s on their plane then they are unconditionally disqualified with "did not finish" result no matter how they perform otherwise.

What's the purpose of this restriction? Is this to prevent the airplane from falling apart or pilot getting unconscious during the (low altitude) race?


texts: Portable radio for cockpit communication

texts:
I am a private pilot based at Van Nuys airport in Los Angeles. Recently due to traffic congestion we have to hold short for extended periods of time, 20-25 minutes.
I thought to get a portable radio to be able to turn the airplane engine and master switches off and save on the rental fee and the constant breaking.
Any recommendations about the specifications of a say 5-10 nautical mile range portable radio is appreciated.


texts: What would be the best alternative during a dead-stick approach?

texts:
(Disclaimer: I am not a pilot so my understanding of things may be really broken)

If a plane has lost engine power, has limited altitude to work with, and is upwind of a landing strip, and the pilot doesn't believe she has enough glide range to pass the appropriate runway and turn around for a landing into the wind on the full length of the runway, would it make more sense to

(a) land directly on the full length of the runway, accepting the tailwind

or

(b) pass part of the runway, turn 180, and land into the wind using only, let's say, half the runway length

Assume that an emergency has been declared, airspace and runway are all cleared, etc. In my particular scenario we're talking about a single-seat, single-engine fighter-type plane with generally poor glide ratio. I'm curious about any contributing factors.


texts: Do commercial lavatory suction systems create pressure mechanically or naturally?

texts:
Modern Boeing and Airbus aircraft employ a suction system for the lavatory on board. How is this suction system powered? By utilizing an on board suction pump or natural pressure and velocity difference from outside the aircraft during flight?

One way to find out would be to try a flush while plane is on a taxiway, but access to the lavatory during that period is not allowed.


texts:
This concerns the GE90X fanjet engine which generates 130,000 LBS of thrust at takeoff.
But for this example the engine is secured to a test mount, and under "full throttle", the thrust generated is still 130,000 lbs.  I believe that 80% of the thrust is from the fan itself.. but let's go ahead and assume 100% of the thrust is generated by the fan only.
If the large 12-foot ducted fan were instead connected by shaft to an external electric motor or gas engine, how much horsepower would be needed, to sufficiently spin the large ducted fan, to generate 130,000 pounds of thrust ?


texts: Does Raymer's installed engine equation include the weight of the pylon?

texts:
I am currently modelling an aero engine and require the weight breakdown of the individual components, I have the dry weight of the engine and need to verify the pylon and nacelle weight.

Raymer has presented an equation for the weight of the installed engine in his book
$$W_{InstalledEngine} = 2.575 *(W_{Engine})^{0.922}*N_{engine}$$

Does this include the pylon?


texts: "What's our vector, Victor?": What does this mean?

texts:
In Airplane there is a famous sequence:

Roger Murdock: Flight 2-0-9'er, you are cleared for take-off.
Captain Oveur: Roger!
Roger Murdock: Huh?
Tower voice: L.A. departure frequency, 123 point 9'er.
Captain Oveur: Roger!
Roger Murdock: Huh?
Victor Basta: Request vector, over.
Captain Oveur: What?
Tower voice: Flight 2-0-9'er cleared for vector 324.
Roger Murdock: We have clearance, Clarence.
Captain Oveur: Roger, Roger. What's our vector, Victor?
Tower voice: Tower's radio clearance, over!
Captain Oveur: That's Clarence Oveur. Over.

Regardless of the silly dialogue, when the captain asks "What's our vector, Victor?" what is he referring to? Does the scene refer to actual issues that one might discuss with air traffic control?


texts: How to get from IAS in MPH to KCAS using POH graph of best TAS/GPH?

texts:
My understanding is that in order to find the V(L/D)max I can do the following steps:

Look in the Pilot's Operating Handbook (POH) and find the performance reflecting the best TAS/fuel flow.
Find the KTAS for the determination from step 1.
Use a flight computer to get the KCAS from step 2.
The number from step 3 is V(L/D)max.
V(L/D)max / 1.316 = Vbe
V(L/D)max * 1.316 = V-Carson

While this sounds logical, I do not see any clear path from step 1 to step 2.

I looked up the definition of TAS, and it is related to EAS.  But when I look up EAS, it is dependent on TAS.  So when you do the algebra, it simplifies down to TAS = TAS and EAS = EAS, which is nonsensical, circular, and unhelpful.  Maybe I am not looking at the right equations, I’m not sure.

Do most pilots have flight computers with which they can determine KCAS starting with the value described in step 1?  If not, how should this best be done?  I could estimate air pressure using altitude, though it would not be very accurate, but I feel like there must be a better way given the large amount of instruments and tools available to most pilots in the cockpit.


texts: How does the Airbus auto takeoff system work?

texts: Can you explain in a easy way, how the auto take off system of Airbus works? What is needed on a modern aircraft to perform the take off without help by a pilot?


texts: All I am aware of is that flutter testing involves the aircraft shaking violently. How is a flutter test performed and what is its purpose?


texts: Is the purpose of variable pitch propellers to maintain an optimal angle of attack?

texts:
I recently had a discussion with an aviation expert, who works as a Flight Instructor, about constant speed propellers - variable pitch propellers - on light piston aircraft.

I have always known that these kind of propellers are capable of changing their pitch angle in flight in order to keep propeller blades at their optimum angle of attack across a wide speed range, while maintaining constant RPM. Therefore, they are very efficient over a wider airspeed range compared to fixed pitch propellers. A change in TAS in flight, for example, would lead to a change in pitch, in order to restore the optimum angle of attack of the propeller blades.

To my surprise, the instructor told me that what I knew about variable pitch propellers was not true: he explained to me that a change in TAS during the flight would lead to a change in the angle of attack of the blades, but that doesn’t mean that the resulting pitch change would lead to the optimum angle of attack.

His answer really surprised me, so I am now wondering what is the purpose of variable pitch propellers then. I understand that there may be a point where the PCU and CSU won’t be able to adjust the pitch to the most optimum angle of attack, but I thought that during normal operating speeds the purpose of this kind of propellers was to provide the blades with the most efficient angle of attack. Am I wrong?


texts: What is "company compensation fuel" and "pad fuel"?

texts:
I tried to find the definition of these fuels but I could't.

Does anyone know about company compensation fuel or pad fuel?
In which document can I find the definition of these fuels?


texts: Why does a plane need to be grounded while fueling, but we never ground our cars? Does the potential for a spark magically exist for an airborne vehicle but not for an earth bound one?


texts: Why can't wing-mounted spoilers be used to steepen approaches?

texts:
In a comment on this answer to my previous question about tail-mounted airbrakes (lack of), @JohnK states:

  You won't see flight spoilers (speed brakes) being used to steepen approaches. You have to be 10kt above Vref to extend them on a CRJ900 and you shouldn't be that hot in the first place, and you aren't allowed to use them at all below 300 ft.

Why do you have to be going abnormally fast to slow down with the spoilers, and why can't they be used at low altitude (especially given that, just like with airbrakes, it would seem to me like spoiler extension would be a safer method of slowing down than pulling the throttle all the way back would be, since, should a go-around become necessary, the spoilers can retract a lot more quickly than the engines can spool up from idle to TOGA)?


texts: Approach when weather condition is below minimum

texts:
If airport weather condition is below minimum, but pilot report that flight weather condition is above minimum, Does controller can issue approach clearance to pilot?
If weather condition get worse than published minimum, should pilot cancel his approach and execute missed approach even in final approach phase?


texts: I have been unable to match this USAAF biplane with a similar photo mainly due to the cockpit canopy. I've found no other like it.  I believe the photo was taken at Madison, WI or Chicago, IL in the 1930s.  Written on the photo was "Douglas Military Observation Plane." I am hoping to find out the make, model, version, and if possible the Military Unit.


texts: Does the sterile cockpit rule mean flight attendants could not inform the pilots if a passenger is in the lavatory while on final?

texts:
Context:
I've seen this interesting question just the other day, asking what would pilots do after receiving this information while on final:
either go around or continue with the landing.

However many others mentioned the Sterile cockpit rule under 10,000ft. Meaning that they could not discuss this issue.
So what would this mean exactly? The flight attendants could inform the pilots but they can’t respond?? Or the FA’s just can’t/won’t inform the pilots about the situation at all?


texts: On a Jeppesen SID chart, the climb gradient is not standard, because it's greater than 3.3%. What specifically does the ATS (7.4%) climb gradient mean?


texts:
I am about to take my check ride, but my FAA 3rd class medical is still pending. I have not been denied, just jumping through some FAA hoops.
I have taken and completed the online course for basic med. Am I OK to take my check ride?
The only thing basic med asked is if I had applied for a FAA physical before... which I have.
I haven’t found much on this particular problem, so I’m looking for help. Any input is appreciated!


texts: Where does the air enter the passenger cabin?

texts:
After passing through the packs and turbines, where does the air get into the cabin? On the 737-800, for example. I don't see on the roof any grill to let the air enter the cabin, look:

Source: Airliners.net

Where does the air enter the cabin? According this graphic, the air enters through the roof and exits through the wall:


texts: How does having multiple ATC towers affect airport operations?

texts:
I know there are airports with more than one ATC Tower, though I only know it from my own country (SCHIPHOL - EHAM). This airport has two towers called Tower-Center and Tower-West. Tower-West is built because of a sixth runway (18R - 36L), that wasn't clearly visible from Tower-Center. (They found this out after completion of the sixth runway.)

How common is it an airport decides to built a second tower, and are there a certain rules or limitations before the decision can be made?

Next to that; what are the practical consequences for pilots and ATC's? Do they not only switch between startup- and ground-controllers but also between several ground controllers?


texts: Do biplanes need bigger tail volume coefficients than monoplanes?

texts:
Do biplane ultralights need bigger tail volume coefficients than monoplane ultralights?

Horizontal Tail Volume Coefficient

I understand that biplanes don't need a larger horizontal tail coefficients vs a monoplane of the same total wing area and same wing span. This is because the chord is would be half of the monoplane, but there are two wings, so the "total chord" is the same, so the horizontal tail volume coefficient does not need to increase. I'm told a typical tail volume coefficient for light airplanes is 35%.

I understand that the horizontal tail volume may actually be lower than that of a monoplane if the wings are staggered, the wings acting like a reflex wing and reducing the wing moment, so a smaller horizontal tail volume may be used in this specific case.

Vertical Tail Volume Coefficient

I understand that the vertical tail volume coefficient on a biplane is twice as large  as that of a monoplane with the same span, as there are two sections of span that the vertical tail needs to control. I'm told a typical vertical tail volume coefficient is 3.5% for light aircraft.

Is this correct?


texts: Is there a such thing as an ARINC label for the yaw angle?

texts: Is there a way to check the yaw angle on the ARINC bus? If so, what is the associated ARINC-429 label?


texts: What is the gray zigzag line over V154 between Dublin VORTAC and LOTTS intersection?

texts:
Above Victor airway 154 on the IFR enroute low altitude chart, there is a grey zigzag line between Dublin VORTAC and LOTTS intersection.

What does the gray zigzag over the segment indicate?

Credit: SkyVector


texts: Why are US Regional Airline starting wages so low?

texts:
With 2,000hrs of flight time, a commercial ticket for ASEL and AMEL, CFI, CFII, MEI, and a Master's in Aeronautical Science I could easily qualify to fly right seat for a regional airline, but I just can't compete with pilots willing to work for \$17k/yr. For comparison, federal minimum wage is currently just over $15K/yr.

Why are the starting salaries at US Regional Airlines so low?
It seems odd that pilots go through extensive training which takes a great deal of time and expense, but they have to be prepared to work for what is a very low salary compared to other jobs that require a high level of skill and education.

Supply and demand is one explanation, but I really don't understand how there is so much competition for flying jobs but at the same time there is a supposed "pilot shortage".
Are there really so many pilots out there that the competition for jobs drives down starting salaries so low?

I am hoping to understand why it is that well-qualified pilots appear to have so little earning power in the marketplace.


texts: I was wondering the other day, during the trans sonic regime, when the velocity over the airfoil becomes supersonic,why does the shock wave standing on the airfoil moves downstream when the free stream velocity is further increased?


texts: What are the ways to burn fuel faster in case of emergency without fuel dumping system?

texts:
In many cases, the maximum landing weight of an aircraft is lower than the takeoff weight due to the amount of fuel it carries.

While some aircraft have fuel dumping systems, others like the A320 family and Boeing 737 do not, and so have to cycle nearby until they have burned enough fuel. (And in case they have to land immediately, they will simply to, but need further inspection due to the high stress on brakes and landing gears)

My question is: If an aircraft has to cycle to burn fuel, are there measures to burn fuel faster? Lower altitude requires more thrust and so needs more fuel, but are there more ways? Like a slight air brake setting?


texts: Why don't commercial aircraft have variable sweep wings?

texts: I was wondering why commercial aircraft don't have variable sweep wings just like the Bell X-5 did? By sweeping the wing further at high altitude it helps the aircraft move faster and also it helps the aircraft to maintain enough lift during takeoff by simply changing the sweep.


texts:
What is motive flow and why is it used in some aircraft hydraulic systems? Why is motive flow used in favor of alternative means of causing fluid flow?

By hydraulic systems, I mean any system that moves a fluid whether it be fuel, oil or some other fluid.


texts: Is the EASA RT License valid internationally?

texts:
I am planning to get a PPL license in Czech. As part of the PPL license I should get a RT License (in English, not Czech).
Is that license is international? I mean, if I want to rent an Airplane in another country in Europe (like Hungary), should I get Hungarian RT license? or my Czech RT license is valid for all EASA countries?
In addition, is the PPL EASA license (with valid RT license) sufficient to rent aircraft in Europe?
Or do I have to pass some test for each country?


texts: How many plane crashes are prevented by pilots?

texts: Statistics about plane accidents consistently show pilot (or other human) error as the leading cause of crashes. With current advances in technology, it is therefore tempting to strive towards replacement of pilots with automated systems. However, I have never seen a tally of how many plane crashes are actually prevented by pilot skill, that would otherwise have resulted in loss of life. Are there any statistics available on this subject?


texts: How can I calculate the speed gain from using multiple STC modifications together?

texts:
Looking at a parts manufacturer website, they list various STC'd modifications for Mooneys with estimated (cruise?) speed gains for each.

However, I've heard that those gains are not additive. For instance, if you applied three mods with 5mph gain each, the total gain would be less than 15mph.

Is there a way to calculate what the gain should actually be if you applied several at once, assuming the gains listed are accurate when applied in isolation?

Most appear to be aerodynamic improvements (i.e. reducing drag) but a few are engine improvements (i.e. increasing thrust). I'd prefer an answer that addresses both sides in an integrated way, if possible.


texts: Is it possible to integrate an AI CoPilot on existing planes?

texts: Or a new aircraft would have to be designed for such a thing? I have little knowledge of aviation, so please feel free to fill me in the required bits.


texts: How is the aircraft stand vertical lux measured?

texts:
How is the vertical lux measurements taken for aircraft stands? Is it 2 m above the ground with the lux meter facing the light source, or parallel to the centreline?

What is the purpose of the lights on the stand? Is it for the ground services or the aircraft?


texts: What is the thing in the middle of the turbofan?

texts:
I have been understanding more about engines lately, but I can't figure out what the section in the middle of a turbofan is for:

What benefit does this part provide to rotating the air? Is it some kind of separate fan or something?


texts: Can I use a rental airplane to conduct air tours?

texts:
Can a commercial pilot perform non-stop air tour operations under part 91 within 25SM of the airport using a rental airplane from the FBO?

I noticed that in the LOA application, the operation needs to provide:

  Type of aircraft, registration number(s), and make/model/series;

I wonder if this has to be the operator's own aircraft?


texts:
14 CFR 121 and 135 certificate holders are required to maintain operational control of their flight operations:

§135.77   Responsibility for operational control.
Each certificate holder is responsible for operational control and shall list, in the manual required by §135.21, the name and title of each person authorized by it to exercise operational control.

121.533, 121.535, and 121.537 contain similar requirements for 121 carriers.

What exactly is "Operational Control"?


texts: It may be a simple question and I've read the PHAK and searched online, but I can't seem to understand why adding moisture to a dry cold air mass would create fog. I understand when an air parcel is cooled to the dewpoint neared the surface, it will become saturated and fog appears. However, why would adding moisture create fog?


texts: What's the technical name of the side window on Boeing and on Embraer?

texts:
On Airbus, the window beside the Captain and the First Officer has the technical name of SIDE WINDOW.
What's the name on other aircraft, or they have the same specification?


texts: What is the correct IATA airplane designator for the Boeing 787-10?

texts:
Wikipedia claims 781, most other sources say 78J.  I can't find anything authoritative, and IATA has the gall to want US$578 for the answer.  Which one is it?

Update for clarity: Everybody agrees that the four-letter ICAO code is B78X. I'm interested in the three-letter IATA code.


texts: How does one differentiate a "fly by" from a "fly over" waypoint?

texts:
I am referring more to Terminal Area Procedures (SID, STAR, Approach), rather than en route waypoints, airways etc. How do I know if such a waypoint is a "fly over" or not?
Especially for some RNAV procedures, where the turn to join the final approach course can be 90 degrees. I have already read the "Fly over or fly by question" but I did not find a reply to the above, although the example quoted and shown in that question was a very good example of what I am asking.


texts: How complete is our understanding of lift?

texts:
I'm currently studying for my PPL and one of the accepted textbooks contains the following disclaimer at the end of the Principles of Flight section on lift:

  It is important to note that the forgoing explanation of lift, and its reliance on Bernoulli's theorem, is very much the 'classical' theory of lift production and the one on which the exam questions are usually based. There are differences of opinion amongst scientists on the subject....[snip]

The same book previously also describes the venturi theory which NASA discredits.

Additionally, one of my previous CFI's told me that during a previous successful job interview he had been asked to explain lift and had merely responded with "Which theory would you like me to cover?"

On the contrary - we must have an excellent understand of some components because of the way we're able to design and build such stable (and unstable when we want) aircraft. Plus, I see some absolutely incredible mathematics described on this website which seek to accurately answer complex questions.

So, my question isn't how is lift generated -it's how complete is our understanding? Which bits are still in dispute, and which bits are fully accepted?


texts: How does the capacity of 2 parallel runways compare to single runway?

texts: Under IFR, what is the capacity of 2 near parallel runways and how does it compare to mixed mode single runway?


texts: Why can't aircraft be cleared to land before the preceding aircraft turns off the runway?

texts:
For example, let's say we have an Airbus A330 in front, which has just landed, well past the threshold and looks like it's going to be alright. Next in line to land is a small general aviation aircraft, such as a Cessna 172.

Now it looks like there's little to no risk of the two aircraft colliding and there's already more than enough space to stop the aircraft, so why can't a controller use their judgement to be able to clear the aircraft behind to land? It seems like that it's a waste of time when you know that there's going to be more than ample time for the previous aircraft to turn off, so what's the problem with that?


texts: For a teardrop shape, which orientation has the least drag?

texts:
Here's the shape:

(Well, that's a cross section of the shape. The actual object is a 3D shape obtained by rotating that outline around the y-axis.)

Let's pretend it's a solid, rigid object flying through the air. It can fly point-first or curve-first. Which way produces the least drag?

Assume it's normal air at room temperature. The angle of attack will be constant. It will be subsonic speeds.

BTW, is there a huge difference in drag? If not then it doesn't matter much.


texts: What does "zero offset between two waypoints" mean in ICAO Doc 4444?

texts:
My question is with reference to the GNSS based separation specified in ICAO Doc 4444. Could someone explain the significance/meaning of the condition "zero offset between two waypoints" criteria?

if an aircraft had deviated, say due to weather, but is able to proceed direct to a particular waypoint, can the GNSS based separation still be applied with respect to another aircraft if we are able to establish that the two GNSS tracks are 15-135 degrees apart (but not on route)? It is this context, that I wanted to know the significance of "zero offset" clause.


texts: Are there any "captains-only" airports in the U.S.?

texts:
Some airports in the world only allow captains to take off or land the aircraft, due to airport design or environmental conditions (obstacles, high winds).

Examples include:

Funchal (Madeira, Portugal)
Heraklion (Greece)
Paro Paro (Bhutan)

Are there any airports in the United States that are "captain-only", either for take-off or landing or both? Why so?


texts: Why divide the blades of a 9 blade propeller into 3 groups?

texts: In a youtube video an airboat is featured with two contra-rotating propellers, each holding nine blades. Interestingly those nine blades are not spaced evenly, but grouped into three groups. I've never seen such an arrangement before, and I expected an evenly spaced configuration to be more efficient. What could be a reason to prefer this grouped configuration?


texts: Are there any regulations about the distance between destination and alternate airports?

texts:
I didn’t notice any distance regulations or recommendations regarding how far away an alternate airport may be. However, it is reasonable that,

Too close: The weather between the two is likely to be similar. If you are unable to land in one, you are unlikely to land the other.
Too far away: The fuel reserve is a concern, and we lose the purpose of the trip.


texts: As a plane gets slower, why does a certain bank angle make you turn faster?

texts:
In the video "Maneuvering during Slow Flight" the narrator states that while flying slow the airplane will be less responsive to aileron and other control inputs. He also says that the plane will turn quicker at a certain bank angle than it would if the plane was flying at normal speed. My question is: why does the plane turn quicker when flying at a lower speed?

So basically what I am asking is, as a plane gets slower, why would it start turning faster then it was when in fast flight?

The part of the video I am confused about is at 1:16


texts: How does the position of the center of pressure change with the use of different high lift devices?

texts:
How is the position of the center of pressure affected by different high lift device deployments?

My guesses are:

When I use a high lift device that just increases the chord length, it moves backwards so that it stays at the same percentage of the length of the chord - correct?
When I use a high lift device that moves downwards, it has the same affect as increasing the AoA (or in fact: it does increase the AoA), so the center of pressure moves forward

Are those two guesses correct? Which other influences are there from high lift devices on the position of the center of pressure?


texts: Why has flight UA106 such a strange predicted flight path?

texts: I was looking at the predicted flight path for UA106 from IAD to MUC and noticed this odd pattern. Why would it do this? I understand that most flight paths are not straight and there are airways that most all flights follow, but this path makes two less than 90 degree turns. Wouldn't it be simpler to go straight to the Belgium point rather than go to Poland, then back to Belgium, then back again to Munich?


texts: Why don't planes fly directly to their destination?

texts:
Here is the flight path for B62554 from PBI (Palm beach) to JFK. This flight almost goes back on itself when off the coast of South Carolina.
I was wondering why this flight takes such a contorted path? Another example is B6242 from Havana to JFK, which similarly diverts out to see when near New Jersey then comes back at an almost 90 degree angle.


texts: What is the expected reaction of a civil airliner pilot upon an invalid request from a fighter jet?

texts:
After asking a question about the recent diversion/pirating of the Ryanair flight in Belarus (that got closed, but has a nice answer), I got to wonder about how the pilot should have had behaved in that case (fictitious situation of a flight over Lithuania, Belarusian jets requesting it to fly back to Belarus).
What are the rules for a pilot of a civil plane when they are requested by a military plane (a fighter jet) to follow them, when the plane is from another country than the airspace?
I can understand that within an organization such as NATO, a Polish plane could fly over Germany to intercept a Singaporean plane (because of NATO agreements).
From the perspective of a civil airplane pilot - does it matter? In other words my questions are:

is the pilot expected to make a decision about whether to follow a military plane at all? (= if they see a plane that requests them to do something, should they follow the requests no matter what?)
is there any consideration of the airspace? (= should the pilot take into account the place they are above?)

I would like to highlight that I am interested in the rules on how a pilot must behave (and not acts of bravery or something like that).


texts: How are CPDLC VHF messages transmitted between ATC and aircraft?

texts:
I'm trying to read up on some of the new developments in ATC (ATN, FANS etc.) and I've come across CPDLC: Controller–Pilot Data Link Communications. In particular, I'm confused of how the VHF messages travel to and from Air Traffic Control and the aircraft.

For the oceanic/remote flying, transmitting messages over SatCom sounds entirely reasonable. But everything I can find on VHF seems to imply that they use a separate Datalink Service Provider, similar how ACARS functions.

I always thought ATC had a bunch of antennas on the tower roof to do voice VHF. If this is the case, what prevents ATC from having their own datalink transceiver and doing all of this stuff 'in-house', avoiding more parties and infrastructure?


texts: Can someone tell me what kind of airplane this is?

texts: It says Capt Nungesser on the tail. I’ve researched him but can’t find out what type of plane this is. French?


texts: Should a pre-flight inspection spot snakes on a plane?

texts:
In January 2013, a python hitched a ride on plane, unfortunately exposed on the wing after getting sucked out of its hiding place.

Qantas 191 is a Cairns → Port Moresby flight on a DHC-8-400, probably the first of the day.

Having done walk-arounds for a Cherokee, I would like to think that I wouldn't allow such an event to happen on a small plane.  On the other hand, I realize that it would be impossible to do a thorough inspection on, say, an Airbus A380.

What is a typical preflight inspection checklist for a Dash 8 or similar plane?  Would it have included, for example, a visual inspection of the flaps that would have allowed the snake to have been spotted?


texts: Why would engine fire cause loss of control?

texts: I was wondering why engine fire would cause of loss of control or crash. There is loss of power and even drag. But could some expert please expand on the troubles of a engine fire?


texts:
What are the dimensions of the protected space provided by a holding pattern? Where and how does the FAA define this?

While this question may contain the answer, this question concisely asked something that is a valid aviation question and it warrants its own answer.


texts: Why is there no anti ice system on inboard slats of A320

texts: I was going through FCOM of A320 and it was mentioned that there is no anti ice system for inboard slats.


texts: Can a free-falling aircraft with no horizontal (or minimal horizontal velocity) start up and fly to safety?

texts:
Inspired by this Grand Theft Auto gif, an aircraft with its engines initially idling is dropped from a high altitude (such as from the top of a building) with no or minimal horizontal velocity. Can it successfully throttle up and fly to safety? How about for

A fixed-wing aircraft, and
A helicopter


texts: What is the purpose of the small wheel at the end of the F-14’s launch bar?

texts: At the end of the launch bar (catapult strop link) on the F-14 airplane, there is a small wheel. Does anyone know what this is used for?


texts: While flying, how do I contact someone who is on the ground?

texts:
As a regular General Aviation pilot, how do I contact or relay a simple message to someone on the ground? For example, to update a friend, family member, or taxi company with an ETA or a meeting point. Assume that asking them to follow a tail number on something like FlightAware would not suffice.

Cell phones are not an option. FAA AC 91-21.1B prohibits cellular communication while in flight (Correction: see comment below; it's really the FCC that prohibits cell use), and cell reception above 5000ft AGL is pretty poor.

Commercial operators have access to more sophisticated services like ACARS, ARINC, or satellite communications, but these are usually too expensive or complicated for the regular GA pilot.

Can Flight Service Stations (FSS) call someone and relay a short message for me? Has anyone tried this?


texts:
Why, until recently, were smooth nose sections not popular? By smooth I mean without a break between the nose and windshield. (The question focuses on airliners.)

Seeing the Starliner (left) and DC-7 (middle), which were vying for the transatlantic market, with their almost perpendicular windshields, I wonder if they were more slanted and followed the nose -- like the Commando (right), for example, which proves it was possible -- enough drag reduction would have helped their payloads on windy days.

The Commando style windshields only made a comeback with the 787 and A350 -- the 747 gets close, but like the 75/76/777, there is still a break.

Manufacturing difficulty:
I don't think that's the reason (unless proven otherwise), because the noses are already smooth. The nose could start from the top surface of the fuselage, and cut-outs to be made where the windshield panels would go.

Windshield materials:
Plexiglas was used early on and on wartime aircraft with complex curvatures.

Image sources:
- https://imgur.com/iA7tbFV
- https://airandspace.si.edu/multimedia-gallery/dc-7jpg
- http://www.historynet.com/going-commando.htm


texts: What are the main sensor value that cause High pressure compressor fault in turbofan engine?

texts:
I have read the paper "Damage Propagation Modeling for Aircraft Engine Run-to-Failure Simulation" (Reference).
 I am doing analysis to find which sensors to monitor for the faults injected in the simulated datasets.

One such fault is high pressure compressor which caused the engines to be marked as failure.

My analysis gave me the following sensors:

Corrected fan speed (NRf in rpm),
Physical fan speed (Nf rpm), and
Engine pressure ratio (P50/P2).

I could not find the proper answers online. Could anyone be kind enough to ascertain how related are these sensors for the occurrence of HPC fault in a turbofan engine.

I'm not from the aviation background. I greatly appreciate any valid suggestions/references or answers.


texts: Why did this aircraft take off in the opposite direction compared to the one used by other flights right before/after it?

texts:
I recently took a weekend trip to Naples and went to admire the city from above at the Certosa di San Martino panoramic viewpoint which, it turned out, was also offering a distant view at NAP operations that morning (June 15, 2019, around 12PM CEST). After taking a few pictures I couldn't help but spending a good 15 minutes tracking a few landings and departures with the FlightRadar app.

Runway 24 was in use at that time, except for a single departure in that timeframe which used runway 6.

Is this a common scenario - i.e. a single aircraft taking off from the runway opposite to the one currently in use?

I know the general factors taken into account when determining in which direction a runway is used, but what could be the reasons behind such a sudden and isolate (takeoffs and landings just 3 minutes before/after used runway 24) change in the airport operations?

The aircraft in question left NAP with more than 1 hour delay, leading me to think that it could have been pilot's request to spare a few minutes: probably positioning for 6 was faster from their gate?


texts: Can pilots land an aircraft with only the use of throttles?

texts: Presuming that all other means of controlling an aircraft are unavailable to a pilot, can a pilot land a commercial airliner safely by using only the throttles and are pilots trained to do so?


texts:
What aircraft has the highest critical Mach number? The highest I heard of was BAC/English Electric Lightning at Mach 0.95. Are there planes with higher Mcrit. and is it plausible to go higher than that in a manned plane?

Note: Critical Mach number is the lowest flight Mach number when the speed of sound is reached locally on the airframe.


texts: Does low pressure induces high velocity or high velocity induces low pressure? I am wandering what is the cause and what is the result. I mean i.e. Bernoulli principle or situation in the core of a vortex.


texts: What do pilots landing on aircraft carriers do when the ship is not visible due to weather?

texts:
Say an aircraft takes off of a carrier to do a mission somewhere, and upon returning to the carrier the pilot comes to find that a thick layer of fog has formed just above the surface of the water in addition to low-level clouds. The pilot may have the ship's exact location, but is it still possible to land?
In the civilian world, usually IFR minimums are 200 ft. AGL, but I am assuming this doesn't apply to military aircraft out at sea, mostly because the ocean is usually a flat surface at a known altitude, (0 ft. MSL), and therefore the risks of terrain other than the surface of the ocean would not be a factor. I also assume they don't apply to carrier-aircraft because, well, they're the military.
However, if the ship is completely shrouded by weather, what would the pilot do? Are there instruments/procedures used to execute a super precise spot-landing with virtually no visibility? What if the plane is bingo fuel?


texts: What is the relation between airspeed and altitude at fixed throttle setting in a private jet?

texts: In the world of private jets, say a G-450, at a fixed throttle setting, does it simply go faster the higher it climbs/flies?


texts: How is the fuel quality monitored/assured for jetliners?

texts: With tens of thousands of flights daily, many out of smaller and perhaps 'sketchy' airports, it would seem that serious incidents caused by contaminated fuel should happen a lot more often (in a quick Google I only found two). Do commercial jets have some system whereby the airplane itself can verify fuel quality as it is loaded? Or do pilots & airlines rely entirely on the fuel supplier?


texts: Could the Aurora D8 have Ramjets instead of traditional jet engines?

texts: By the  design of the Aurora D8, the engines would receive the boundary layer of air atop the fuselage, however, because jets have what I am calling "moving parts", and the pressure differences would cause problems for the turbines. Could we eliminate this factor with ramjet engines?


texts: Why is New York-London used in time measurement for aircraft?

texts: Looking around aviation news and history, I see that many commercial aircraft are touted to have this or that much time fly between New York and London. What caused the route between these two cities to be used in measuring the "speed" of the aircraft?


texts: How much can a plane deviate from its route to Paris (CDG and ORY) before an alert is raised?

texts:
I was reading about the 9/11 hijacks and the Wikipedia information about flight AA 11 mentions that

  Of the four hijacked aircraft on 9/11, the nine minutes of advance
  notification about the hijacking of Flight 11 was the most time that
  NORAD had to respond before the aircraft crashed into its target.

I am sure that these tragic attacks have lowered the bar in terms of time to react to a off-route deviation by planes and was wondering what this means for flights to the Paris airports CDG and ORY.

I have just taken a snapshot of the flights (courtesy of flightradar24)

and it seems like (quite understandably) that planes avoid Paris intra muros. This said, they are quite close and the ~20 km distance from Paris is a ~2 min flight.

Since the closest airports which may host Rafales are I believe Le Bourget and Vélizy-Villacoublay, the interception planes would need much more than that to be on their tracks before they entre Paris.

With all this said, how much can a plane deviate from its path before Paris before it is intercepted (and brought down a way or another)?

Note: while I am particularly interested by Paris (living there) I can understand that the information is classified (though probably easily guessable for someone who knows about aviation). In that case another public information is welcome to understand how things changed after 9/11.


texts: What does feathering mean and how does it work technically?

texts:
Before I ask "What does Feathering mean when it comes to Jet/Propeller Engines" I have to say what I think I know:

Feathering jet/prop engines mean achieving a sufficient turbine rotation speed at which, the general functionalities such as VFG drives (elec), pumps, etc. could start operation.

I would very much appreciate an explanation with any anomalies.


texts: Why do cabin crew also man check-in desks?

texts:
When flying, I sometimes notice that the person behind the check-in desk also turns out to be the flight attendant on my flight.

Is this always the case, or did I just notice the exceptions?
Why do airports use cabin crew for the (comparatively) simple job of checking bags, which could in theory be done by (presumably) cheaper lower-skilled employees? Or am I underestimating the difficulty of checking bags?


texts: How can I read airport maps when choosing a seat as a passenger?

texts:
When I choose seats on an airplane, I usually go for a window seat since I love the view, especially the views of a city on takeoff/landing.

Sometimes I get good a view of the city and sometimes I don't.

How can I look up information on an airport before a flight to choose a side of the plane that will get the best view of the city?

To give a concrete example, I will be flying into DFW soon from the North. Ideally I would get a view of downtown Dallas (East of the airport) when flying in. From AirNav, and the map it links to, I can see the runways at DFW run North/South. If I pick a seat on the left side of the plane will I be guaranteed a view of downtown Dallas?


texts: What is the Space Shuttle's command law?

texts:
The Space Shuttle was fly-by-wire. In today's fly-by-wire systems, the command law commands either the load factor and the roll rate (e.g., A320's normal law), or the surface control deflection (e.g., A320's direct law).
What was the case for the Space Shuttle?


texts:
I always assumed that big runways are flat (or more specifically straight: they might have a slight slope in either direction), but while watching some crosswind landing footage shot at Birmingham Airport I noticed that the runway looks really uneven, and based on the videos it looks like this hinders safe landing especially in adverse weather conditions.

How common are uneven runways like this?
Does an uneven runway make landings more difficult?
Is there any standard on how flat a runway needs to be?


texts: What is the ratio of actual flight time to simulator time on type for airline pilot training?

texts:
I know that training flying time on large commercial aircraft is awfully expensive but I'm just curious how much training time a typical scheduled passenger airline pilot gets on the real craft these days? In particular I'm motivated by investigation reports that reveal that current simulators may have flaws and shortcomings in realistically simulating some parts of the flight envelope.

I'm sure this varies  a lot by pilot, airline etc. so I'm not at all looking for an exact answer, just a approximate figure.

e.g. Say, I'm flying on a A-320 or a B-787 commanded by a newly type-certified first-officer, what could be the bare minimum actual flight time (not simulator time) on an A-320 / B-787 that he could have had?

PS. What is the type-rating process? Does that have no need for flight time? Can you get Type rated with 100% sim time on type?


texts: How are airlines able to work out gate allocations so far in advance?

texts: When flying on a long-haul flight, you can often see gate allocations for when you land a hour or two before actually arriving at the airport, including transfer information and connecting flights. However, with so many aircraft and frequently changing situations, how do they manage to allocate these gates so far out in advance?


texts:
I remember when I was a child, my parents and me often saw the Aunt Ju flying. But about 5 years later it disappeared. We never saw it again.

Does anybody know what has been the use of the Ju 52 after the 70s?


texts: Can an aircraft continue flying and land safely following an engine failure?

texts: Is it possible that an aircraft could continue to fly and then land safely on a single engine if another stopped working?


texts: Does the glide slope flag detect percent of modulation (80%)?

texts: Please advise if the glideslope flag validates that the received frequency is being modulated at nominal 80% or 40% for a localizer.


texts: When can I descend on a feeder route if instructed “maintain ... until established”

texts:
AIM 5-4-6 discusses how Approach Clearance applies to feeder routes. It says that when ATC clears an aircraft for the approach, the aircraft is expected to use a feeder route if applicable. My understanding is that this includes the altitude published on the feeder route.
However, if ATC says “maintain 2000 until established, cleared approach” and the aircraft is approaching a feeder route, when would the aircraft descend to a published altitude? On the feeder? Once past the initial approach fix?


texts: Why did the RAF buy the F-35B model and not the A model

texts: If the only issue is the in-flight refueling system (probe/drogue), wouldn't it make more sense to buy the A model and modify the tankers. The refueling issue doesn't compare to the performance penalty (range/internal weapons) of the B model.


texts: What do the Airway Letters and the following numbers mean?

texts: For example, from RCTP - ZGGG the route is AJENT MKG A1 ANPOG R200 GLN W22 IDUMA via the AJENT SID to the IDUMA STAR. What does "A1 or R200 or W22" mean? Are they just randomly allocated letters with random numbers for routes?


texts: Human-powered flight in vs. out of ground effect?

texts:
There is an impressive flight (figure-of-eight) with a human-powered aircraft shown here:

Given the long wings of the Aerocycle 3, can it be considered to fly in ground effect for the whole flight?

Nothing wrong with that - the Ecranoplans are fascinating creations - but how much more power will be needed to lift it out of the ground effect, should it be desired?

Also, this thing is just screaming to be fitted with an e-bike powertrain...


texts: In an emergency, can an airliner land at Pyongyang or another North Korean airport?

texts: If a flight was, say, en route to Seoul, but could only make it to the closest available airstrip and that was Pyongyang, would that be allowed? What would they be met with on the ground?


texts: When and where are anti-ice required for supersonic flight?

texts:
Many aircraft have heating devices to prevent dangerous icing.  Supersonic aircraft rapidly compress the air, leading to elevated temperatures.  Concorde and Tu-144 used fuel as a heat sink.
How fast do you need to fly so that heating makes anti-ice irrelevant?  How does it depend on the part of the aircraft?  Presumably the leading edge is the first part to warm up without anti-ice.  Are icing conditions different at typical supercruise altitudes?  Is there meaningful water up there?


texts: Numerous questions regarding ARINC429 protocol

texts:
I recently made significant progress in my understanding on the ARINC429 thanks to a user on this site, but I after reading more into it, I may have confused myself a little bit. Any help on any of the following questions is greatly appreciated.

I found a specification pdf online, but it contradicts (i think) some of the other information I have gotten. The link to the pdf is here. Is it safe to assume that information is accurate enough to rely on? Assuming this book is a proper document on the ARINC429 specification
If the above is correct, is it correct that BNR data fields are represented in positive two's complement with bit 29 indicating its sign (positive/negative)? Wouldn't that just be regular binary with bit 29 indicating the values sign?
The scale factor applies starting from the MSB (bit 28) and continues halving with each bit between 27 and 11. The actual value translation would be applying the scale factor to each sig bit and adding the values of all the sig bits together to get the final value and using bit 29 to identify if its +/-. Is any of that correct at all?
How does the resolution work? I got confused a lot by that. What is it? How does it affect the data field?
Can somebody explain BNR format of the data field and how to translate it? I feel like I may have read too many different sources and got confused by the variance in explanations....haha


texts: Why is this Instrument Approach NA for certain radials, yet it depicts a feeder route for those radials?

texts:
The RNAV (GPS) 28 at Tampa Intl (KTPA) says

Procedure NA for arrivals on PIE VORTAC radials 356 CW 157

That seems to mean the approach is not available for anyone generally northeast of the PIE VORTAC. Why is there a feeder drawn on radial 085, clearly within the 356 CW 157? Moreover, the whole approach procedure is within those radials east of PIE. Does the NA comment simply mean a pilot must be coming from the west side of PIE when they request the approach?


texts: Backup plane for checkride: Can it be a different model?

texts:
I'm a student pursuing a US Private Pilot License, and recently scheduled my checkride. I've been training in a 1981 Piper Warrior (PA-28-161), but if its annual goes sour I may have to take my club's 1980 Piper Archer (PA-28-181). I have well over §61.109's 40 hours in the Warrior alone, and only ~10 hours in the Archer. I have a separate club checkout and CFI solo endorsement for each, they're pretty similar anyway—they're even both the same ATC type (P28A)—but they aren't the same model.
Here's the catch: Form 8710, the "Airman Certificate and/or Rating Application", asks specifically for

[II.A.2.] Total time in this make/model and/or approved FFS or FTD (Hrs.)

Furthermore, according to the IACRA FAQ ("I'm a Designated Examiner. I noticed a mistake when reviewing the IACRA application...."):

A mistake in the applicant's information cannot be corrected after it has been signed by the Recommending Instructor.

My prospective DPE explicitly told me that the backup plane was fine, and I can't find any Part 61 regulations that are specific to experience in one make/model aside from adding an experimental aircraft as part §61.63(h)(1), which is what I assume the box is really for. Of course I'd rather test in my more-experienced plane, but I'm asking specifically for regulations here if Plan A falls through.
Are there any regulations or headaches that I would encounter if I need to change the tail number or model number of my checkride plane and listed hours therein, potentially long after IACRA submission?


texts: Could the GPS be used to aid the autopilot with speed?

texts:
In the AF447 incident, the autopilot system was offline due to the aircraft's pitot tubes being obstructed by ice particles.

Since the physical condition of the plane in air is cold and risky, the same physical obstruction could happen again and again.

Though the pilot is trained to fly the plane in bad weather, I'm wondering why not just use the GPS to aid the plane's computer? The GPS system could be a secondary source to providing the computer with information for flying, like speed and altitude.

If the GPS could've aided AF447 in preventing the autopilot system from going offline, would the pitot's issue not to initialize the system problem then crash a plane?


texts:
As far as I understand glider pilots like to look out for thermals. I assume that when you are in one, you can perceive that and you can make roughly sure to stay in it.

But what if you're not in a thermal? How do you look for one? Are these methods (like finding a cumulus?) significantly/statistically more efficient than just randomly browsing? Or is it mostly a question of luck?


texts: What front is going to form after a cold air mass meets a warm air mass?

texts:
What front is going to form after a cold air mass meets a warm air mass -- I think it will form a cold front or an occluded front, but I'm not sure.
Today I learned that different fronts gives different weather conditions for flights and I saw the question that I asked and I thought that it will form a cold front because the moving cold mass will collide with the warmer one and it will force the warmer mass to go up. However, I also learned that a cold air mass is moving faster than a warmer one and in the definition of an occluded front it says that the cold one will overtake the warm mass.
Will it form a cold front or an occluded front, or does it depend in what direction the masses are moving?


texts: How do aircraft discern that an ACARS message is being sent to them?

texts: This may be a simple question, but how do airplanes know which ACARS messages are meant for them from the ground? I'm not sure how physically close planes would have to be in order for that to be an issue. Do they simply receive all ACARS transmissions in the area and the CMU checks for this information in the header and continues to route it if it has the proper header? I'm assuming the VHF doesn't perform any checks since the data is still an RF signal at that point.


texts: Why are some non-towered airports charted with an empty circle?

texts:
Guntly Memorial Airport (62C) is shown as an empty circle with four hash marks around the edges. Why is it empty versus some of the other airports around (such as 96C, C89, BUU, etc.) that have a depiction of the runways inside a magenta circle?

Also, do the hash marks around an empty circle mean the usual - that there are fuel services available at that airport?


texts: How can a CFI renew their certificate with the FAA?

texts: I've read that there are several ways a CFI can renew their FAA instructor certificate. What ways are available for a CFI to renew?


texts: Do I need to use an airfield to take off or land a powered paraglider?

texts:
Most aircraft require a runway to take off and land, however powered paragliders simply attach to the pilot's back, requiring the pilot to run a few metres to take off. The landing distance is also very short.

Due to this, why would I use an airfield with a runway to take off and land at, considering only the first few metres are needed, and the pilot would be required to walk along an active runway for a long distance. Why not just use an empty field where there is no nearby traffic and you are not causing delays to flights?

Should I land/takeoff from a runway in spite of this, or simply use a suitable field within reasonable distance of the airfield? What are the regulations or best practices for this in the UK?


texts: How many stripes does a student pilot have?

texts: When a student is finishing a Bachelor in Sc. Aviation, how many stripes does a student have? Can a student have stripes during his bachelor graduation or do they have to go through other PPL courses?


texts: What does the letter E signify for the E-3 AWACS?

texts: I came across the E-3 AWACS aircraft with the designation E-3, I could not find what the letter E means in E-3.


texts: What is this plane seen in Mobile, Alabama?

texts: This was taken at the USS Alabama in Mobile, Alabama. It is probably a US Navy aircraft.


texts: Is there a tool or site where I can see wind vectors overlaid on a prognostic chart?

texts:
I'm hoping to find a source where I can see wind vectors overlaid on a prognostic chart, to visualize how the wind moves around the pressure systems and fronts.

Curious if anyone knows of illuminating and fun weather data visualizations e.g.
https://earth.nullschool.net


texts: Why should the ball be centered during steep turns?

texts:
I was taught to make steep turns with the ball centered, but this seems wrong to me. Shouldn’t the ball actually be held slightly to the inside of the turn?

My thought is that by using some cross-controlled rudder, the elevator pressure can be reduced, reducing the angle of attack and making the turn safer.

Essentially, in a 45 degree turn for example, a standard tail aircraft is turned into a V-tail. Pulling on the elevator is only half effective in keeping the nose up, the other half of the force goes to turning faster.

A knife edge is the extreme form of this, where the rudder becomes the elevator completely and the fuselage the lifting surface. No elevator is used (to keep the nose up. It’s actually used as a rudder instead).

So, if keeping the ball to the inside reduces G-force and angle of attack, keeping the plane further from the stall, why isn’t it commonly taught?


texts: Why do most fighter craft have a center stick?

texts:
Is there a specific reason why in most fighter planes, the control column is between the pilots legs instead of on the sides like Airbus airliners? I know the F-16 has sidesticks, but most of the others have it in the middle.

F-16 Cockpit with sidestick

F-15 with centerstick

Images from Wikipedia


texts: Why is tape being applied to this jet engine?

texts:
When I read this question asking for identification of the aircraft, my immediate question was:

What is that duck tape for?

Whether you call it duck tape or duct tape, why is it being applied to the nacelle?


texts: Why does the DC-9's antiskid system have to be manually disarmed during landing rollout following a ground-shift-mechanism malfunction on takeoff?

texts:
An aircraft's ground-shift mechanism (usually a sensor wired to the nosegear strut that looks to see whether the strut is compressed or not) tells the aircraft whether it's on the ground or in the air.  This determines how the aircraft responds to certain situations; for instance:

Many aircraft's spoilers1 can only extend to the full-up ground-spoiler position if the aircraft is in ground mode.
Applying TOGA thrust with the flaps up triggers the takeoff-warning horn in ground mode but not in air mode, whereas the stall warning, in contrast, can only sound in air mode.
Reverse thrust, on most aircraft so equipped, is generally locked out in air mode, and the minimum thrust available changes from the ground-idle setting to the considerably-higher flight-idle setting when the aircraft lifts off.
The outflow valve on most pressurised aircraft automatically goes to the full-open position when the nosegear strut compresses (this depressurises the cabin, allowing the doors to be opened when the aircraft reaches the gate).

The ground-shift mechanism can occasionally malfunction, in which case fun things can happen, like the engines refusing to reverse upon landing and the stickshakers going off during taxi (if it fails in the "air" position) or the takeoff-warning horn going off when you raise the flaps during climbout, the landing gear staying locked down, and the aircraft refusing to pressurise (if it fails in the "ground" position); the usual workaround is to force the aircraft into one or the other mode using circuit-breaker fu.

One specific type of aircraft (the DC-9) has the following interesting entry in the abnormal-procedures section of the AOM, regarding what to do during landing if the ground-shift mechanism failed upon takeoff:

  Approach and landing:

  If landing gear was not retracted prior to landing, ground spoilers must be operated manually.

  AIRPLANE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. REPRESSURIZE (PNF)

  Ensure airplane is repressurized prior to landing.

  ANTI-SKID SWITCH (before 30kits ) . . . . . . . . . . . . . OFF (PNF)

  During landing rollout and prior to 30 kts, momentarily release brakes and place Anti-skid switch to OFF.

  GROUND CONTROL RELAY C/Bs (if pulled) (H20 and J20) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RESET (C or FO)

  Reset Ground Control Relay circuit breakers
  during taxi and verify that circuits are in the
  ground mode.

  [NTSB AAR-96/07, page 134 (page 144 of the PDF file of the report); my emphasis.]

Why does a ground-shift-mechanism failure require the DC-9's antiskid system to be manually deactivated during rollout?

1: (Though not all.)


texts: Is VOR identification automated in modern avionics?

texts:
Is the VOR identification via audible Morse code automated in modern autopilots / avionics?

Or does a pilot in an A380 still sits in there, listens and compares the .-. .. -.. to her charts?


texts: Can the maximum thrust of a turbofan engine be estimated by its intake diameter?

texts: I have no clue in aeronautics. How to estimate maximum thrust (at any rated condition, such as altitude, speed, rotation velocity- any given condition) by intake diameter?


texts: Under what circumstances does the F-16 and possibly similar fighters deploy leading edge slats?

texts: What does the F-16 (perhaps other fighters as well) use to decide when to deploy leading edge flaps? I would assume angle of attack, airspeed, stick deflection, or some combination of the three, are the main factors.


texts: Are taxiways always one-way towards a specific, fixed direction?

texts: I was studying the airport diagram of JFK and I began to wonder if aircrafts use taxiways as a one-way road. In case they do, is the direction of a taxiway fixed or does it change according to the daily needs of the airport?


texts: How are aeronautical procedures created in the US?

texts: In creating new procedures for an airport, does someone from the FAA go to an airport, examine all their information, and choose what kind of approach/departure (for example) will be created? Or do airport officials advise the FAA (chart creators)?


texts: For FAA currency purposes, must flight time be in an N-registered aircraft?

texts:
I currently hold a Commercial Pilot Certificate issued February,2018. My Flight Review has to be done no later than February 2020.

I have convalidated my FAA License to Colombia. The 90 day currency for carrying passengers applies to both FAA and Colombia.

If I fly Colombian airplanes, does that flight time apply to the 90 day requirement in the U.S.?

In other words, can FAA certificate currency be demonstrated in non-N-registered airplanes?


texts: Are pilots legally required to obtain a weather briefing prior to some or all flights?


texts: What are the registration requirements for US aircraft?

texts:
Where can the requirements for US aircraft registration be found?

What is the penalty for flying an aircraft without a valid registration?

What should someone do if they believe an aircraft to be operating without valid registration, and how could they determine this?

Somewhat related to this other question:
What is the pilot's obligation to verify a registration has not expired?


texts: Where can I find a catalogue or lists of realtime, streaming (major) airport cameras?

texts:
I ask in the spirit of aircraft spotting and would also prefer those with live ATC feeds, like Osaka. As of now, the visual quality is blurry and hazy, but perhaps this is due to low visibility and bad weather?

On the side panel of that, I clicked on another for Narita, but this one doesn't capture the (active) runways.

Is there an efficacious, systematic method to find all such webcams for substantive airports worldwide? Do such manifests or records already exist? I tried a forum thread on FlightRadar24 which cites airportwebcams.net, but these are NOT streaming and realtime.


texts: Does angle of attack change in a sustained climb?

texts:
I saw this question on a closed Facebook group, generating wildly differing answers. So I thought I would ask it here.

You're in a C172 flying straight and level at 5000 feet and 100 knots IAS. You apply full power and go into a sustained climb maintaining this airspeed.

Has the angle of attack increased, decreased, or remained the same?


texts: What is the procedure when an aircraft with an emergency can't land due to a blocked runway?

texts:
This is a hypothetical scenario, but I'm interested to know if there are any regulations/guidance for what ATC should do in this situation.

The hypothetical nightmare scenario:

The runway is blocked by a crashed airliner and can't be cleared quickly.
The airliner is full of injured passengers who will take time to move.
The next aeroplane in line to land has an engine failure and is gliding to the runway (so can't go around).
You're in a hilly/built-up area so other options for landing are limited.

Clearly, you can't have one aircraft landing on top of a crashed aircraft, so what should ATC do?

Some of the options I can come up with (in roughly ascending order of how crazy they sound):

Switch him to a different runway e.g. LHR has two parallel runways (but if he's close to the airport making the sudden move across to another runway might be dangerous without power?)
Empty a taxiway (but you'd probably struggle to empty it fast enough at a busy airport?)
Point him towards a grassy bit of the airport
Allow him to land, but aim to land before or after the crashed aircraft (crash is probably at start or end of runway, so might just work)
Wish him good luck and tell him to find somewhere else to land (you know that's possibly going to result in him crashing, but at least he won't crash into the already crashed aircraft).

So is there any advice for the controller and if so what is it?

Note the source of this question was listening to a recording of the ATC when BA38 crashed at LHR. The controller asks the next aircraft to go around - it made me wonder what would happen if they had said no!


texts: What is the cause of unusually strong wake turbulence from the 757?

texts: The Boeing 757 (at least in the US) is in a special class of its own with respect to air traffic control wake turbulence advisories and separation. This is apparently due to it producing stronger wake vortices than would be expected from an aircraft of similar size and weight. What about the 757's design causes these strong vortices? What led to the decision to treat it differently than similar aircraft?


texts: How are pilots trained to prepare for crashes?

texts:
I once read somewhere that pilots can go to some facilities so get trained for crashes.

  I actually went to a facility in New London, CT where they actually
  dunk you in water strapped in the seat of an airplane upside down and
  with your eyes closed in a big pool.

Is there any formal training for the commercial pilots to be prepared for crashes? If yes, how far do they go in training pilots and for what kind of crashes?


texts: Would a wireless fly by wire system be practical?

texts: Given that most modern aircraft are controlled using the fly by wire system, what is the likelihood or the drawbacks of transmitting those fly by wire instructions from the cockpit and or cockpit computer wirelessly? Wires add weight to the aircraft and hence increase the net fuel burn. I'm assuming a totally wireless system is not already in use today.


texts: How heading bug is calculated during cross wind and tail wind?

texts:
From this question, it is been suggested to ask different question, rather than keep discussing it under comment section.

How is the heading bug calculated and used for navigation when there is a cross wind?
… when there is a tail wind?
Will the heading bug matter for navigation when there is wind correction required?
What role does the heading bug play in autopilot mode?


texts: May planes be flown above the maximum certified altitude?

texts:
Let's take the 737NG as an example. The 737NG has a maximum certified altitude (MCA) of FL410.

However, looking at the MCP, the maximum altitude that can be set is 50,000ft. And the pressurization panel can be set to 42,000ft.  All allowing to fly above FL410.

Please note that I am getting this information from FSX with the PMDG 737. Though a simulator product, it claims to be very accurate model of the plane.

Also, although I am not sure, higher altitudes = fuel savings right?

So this rose the question: Can/May I fly above the maximum certified altitude?

Can I fly safely with an 737NG at 45,000ft for example?

Related: What determines the maximum altitude a plane can reach?


texts: Is a stall warning horn required to fly?

texts: I need an answer in reference to 14 CFR 23.207. I looked there and couldn't say 100% if it was a yes or a no.


texts: Can pilots take multitools on board in Canada?

texts: Can pilots in other countries or Canada carry Swiss army knives onboard on commercial flights? Passengers are not allowed to do that in Canada.


texts: What are the differences between ADS + INS and ADIRS / ADIRU?

texts: What is the main difference and advantage in the Air Data System, between the former architecture (ADS + INS) and the newer one (ADIRS/ADIRU)?


texts: What is the typical space allocated to first class vs. economy class passengers?

texts:
I'd like to know the space allocated to a typical first class passenger compared to that allocated to a typical economy class passenger.

For example, from SeatGuru, I can get the pitch and width of the seats on a British Airways Boeing 747 (economy is "World Traveller"). But can that give me the actual space allocated? Also, the first class seat is an "open suite" - does that mean there's space beyond pitch and width? Anyone ever done this calculation (in square feet or square meters)?


texts: Why after 911; do we not have "fail-safe" transponders that cannot be turned off?

texts: In the 911 terror attack the transponders were turned off.  Who is to blame for the lack of foresight that has allowed another jet liner to shut off their transponders.  This is a ¼ billion-dollar ship; it seems impossible that engineers would not be able to design a safe and reliable back up transponder system that would not jam other signals, and would not be a fire hazard.


texts: Why did this delta wing generate a lower Cl at a higher wind tunnel velocity?

texts:
I'm an aerospace engineering student,and just did an aerodynamics lab in which we measured the lift & drag of a delta airfoil inside a wind tunnel between 0 and 40 degrees, in 5 degree increments, at two flow velocities (subsonic, M< 0.5). For some reason, the lift co-efficient is .25 lower throughout the entire curve in the higher velocity run compared to the lower velocity run, despite the drag co-efficient s being identical until the stall region (which begins at 30 degrees and completely separates at 35). Why is this? Considering the nature of the lab, this seems what I should be discovering. I have a theory that it has something to do with stronger vortices generated by faster flows, but wouldn't that INCREASE lift by dropping the pressure on top of the wing further?

In addition, another oddity: the L vs D curve increases SHARPLY between 0 and 10 degrees for both flows, but then the slope decreases after that and stays steady until the stall region. Why is that, and is that specific to delta wings?


texts: How far away should the vertical stabilizer be from the leading edge of the main wings?

texts: I am wondering what the advantages and disadvantages are of placing the vertical tail nearer to, or farther from, the main wing. For instance, when the vertical tail is just behind the wing, do the wing's effects on the airflow around the aircraft decrease the effectiveness of the vertical tail?


texts: What is the US FAA concerned about when it comes to psychiatric medications?

texts:
I don't understand the FAA's policy for psychiatric medications (specifically anti-depressants). Obviously I'm glad there is oversight into who can obtain a pilot's license for the safety of the pilot, crew, passengers, and the people on the ground. And obviously people need to be in a stable condition before they eligible to fly. But some of these rules sound ridiculous to me.

First, they won't approve you to fly while taking a psychiatric medication, but they may approve you to fly if you decide to go off of it for 60 days.

What?

So basically if you have a chronic mental health condition, and you are taking a medication for it, and it's working well without side effects, it's better to go off the medication before you try flying? Wouldn't the disease be more apt to return if you were off the medication, than on it? That sounds like a very stupid risk for the FAA to take.

Are they worried about side-effects? Most of the side effects for modern SSRIs are very limited and/or transient and/or don't apply to flying (like constipation), so I know they can't be worried about those.

Are they just concerned about withdrawals if you miss a dose? That seems pretty unlikely to happen, and probably less likely to cause trouble than to go off meds entirely.

Basically, I don't get it. It seems that if you are fully-treated for a condition without side effects that you should be eligible to fly, regardless of whatever drugs are put in your body. Honestly, I'd be more concerned if people were taking less medications for passing a test, than what they were on before.


texts: How does fuel flow and altitude affect the compression ratio of jets?

texts: Does the compression ratio of jet engines change with altitude and/or with the rate of fuel flow?


texts: Wind tunnel- test section design question?

texts:
1)Why test section room is so so big,is this because to reduce interfrence  between test object and walls?
2)Is test section room open to outside atmopsheric pressure or must be  100% air proof?
3)How they achieve clean airflow where test object stay if test section room is much wider than nozzle and collector,isnt air mixing with air jet?


texts: RNAV (RNP) Approach Height Loss Question?

texts: While viewing the following approach chart, which is an RNAV(RNP) CAT C Approach, there are several landing minima, stating a HEIGHT LOSS OF 50' AND 150', what does that specifically mean?


texts: What is the big hole at the bottom of the vertical stabilizer on the Boeing 717?

texts:
What is the big hole located on the forward vertical stabilizer's bottom used for?

(Image source)


texts: DP confusion. Do I turn left or right if not told?

texts:
Please take a look at the MIA5 depatarture from KOPF:

MIA5 Page 1

MIA5 Page 2

The instructions seem in conflict. Specifically, suppose you are taking off RW 270R and want the WINCO transition.

The textual instructions are:

climb heading 273°, thence....
....maintain 2000 or higher altitude
and expect vectors to appropriate transition. Expect further
clearance to filed altitude 10 minutes after departure.

OK - that
    is straightforward essentially runway heading to vectors to WINCO.

However, there is a third text segment on page 2 regarding the WINCO transition:

"From over DHP VORTAC on DHP R-322 to WINCO INT"

DHP is a LEFT turn from OPF and would take the airplane directly across the KMIA departure / arrival paths; WINCO is a right turn. Which is it? What do I do in lost comm? Why do they have "from over DHP" I would expect the instruction to be "climb heading 273° to intercept DHP R-322 to WINCO"

Also, if I load that procedure into Garmin Pilot, it just shows a path direct from OPF to DHP then to WINCO which I know is wrong.


texts: Do laser Christmas lights have the same dangers as laser pointers aimed at planes?

texts: With new laser Christmas decorations like this one, a laser appears to shine in patterns on a house for a decorative effect.  If this is aimed so that some of the beams miss the house and go over it into the sky, could they cause problems to planes?  Would the effect be similar to a laser pointer, and could the person with the decoration be prosecuted as shining a laser at a plane?


texts: What is an “aeronautically qualified witness”?

texts:
Many older NTSB AARs, in their history-of-flight-and/or-accident-sequence sections, make mention of observations by an “aeronautically qualified witness” or witnesses, without any further explanation of what this term means.  Example (AAR 76-04, page 3 [paper]/6 [PDF]):

  An aeronautically qualified witness, who was standing near the base of the radio tower when the plane struck, stated that the sky was overcast and that the bottoms of the clouds were obscuring the top 30 feet of the tower.  [...]

What, exactly, is meant by an “aeronautically qualified witness”?  Does it mean “a witness who is themself a pilot”?


texts: Has the United States started a drone crop spraying program for farmers?

texts:
On "NHK World" (2018.06.01), a news segment showed Chinese farmers being taught to use drones to spray chemicals on their crops. The Chinese Government hopes to train all the farmers in an entire province.

Has the United States started any similar drone crop spraying program for farmers?

Is there any speculation on impact to future agriculture pilot jobs?


texts: How does a subsonic jet engine intake design ensure correct air intake?

texts:
I think I understand that inlets are there to slow down the airflow and increase the pressure to stop the compressors stalling?. If this is the case, I don't understand how the nacelle or intake achieves this?

Has it got something to do with the relationship between pressure, velocity and area?

I am only looking for an explanation on jet engines which operate below the supersonic range.


texts: Why most of the supersonic or fighter aircraft use all-moving control surfaces?

texts: What are the advantages of using all-moving control surfaces? can someone give explanations based on aerodynamics?


texts: Does object mass have a significant bearing on wind interference?

texts:
I'm learning to fly RC quadcopters, and before I go outside with an expensive, possibly dangerous (if it were out of control and hit something) large unit, I've decided to practice flying for a while on a smaller entry level "palm" drone (if I lose/break it, I won't be out more than $30).

While trying out the palm drone outside, I've noticed that a very tiny gust of wind will knock this thing out of the sky, or at least into a very different direction then intended. Intuitively I want to assume the larger drone will do better against fair-weather Kansas winds; however I've also learned not to assume that my ground based experience translates well into aviation experience. So

TL;DR

Will a larger, heavier drone be less impacted by wind gusts than a smaller palm drone?


texts: Why are planes flying in a zigzag path over Long Island when approaching JFK?

texts: Every time I've flown into JFK Airport from the east I've noticed that the plane takes a weird zigzag path over Long Island. Why is this? Is it because of noise laws?


texts: Help identifying airfield and aircraft from movie "My Spy"

texts:
Here's a couple of stills from the movie "My Spy" - the climactic scene takes place at a single-strip airfield with a paved or tarmac 09 runway.

My tentative identification of the (clearly unflyable) military planes in the background, from left to right: an Avro CF-100, a F-86 Sabre, then a two seat F-104, and next (judging from the tail) another single seat F-104 in unusual light green camouflage.

The red and white plane in the background, from a later shot, is an F-5 in unusual livery.

The second picture points to the F-86 being RCAF, which would point to a Canadian airfield. On the other hand, the furthest F-104 looks very much to be in Belgian colours.

There's not much more to go on! I wondering where this is, and how these planes ended up there.

"My Spy" 2020 Amazon Films / STXfilms


texts: What is the difference between Angle of Incidence (AoI) and Angle of Attack (AoA)?

texts:
Following discussion here, I am still confused about the difference between AoI and AoA. As I read in many references and watched in many YouTube videos especially this one:
1). AoI is tje angle between the longitudinal axis and the chordline as per design/manufacture. It says normally AoI designed/manufactured is six degrees. AoI remains constant as it is fixed relative to the fuselage.
2). AoA is the angle between the chordline and the RELATIVE AIRFLOW. AoA changes in flight.

My confusion is with the meaning of the RELATIVE AIRFLOW. This phrase confuses me. In my opinion, airflow produced by the propeller or the turbines flows parallel to the longitudinal axis, or at least it has fixed angle, also as per designed too.

To avoid a repetitive question, I want to give this situation.
1). During take off of an airplane, from the airplane start moving until it left the ground, what is the RELATIVE AIRFLOW?
2). After the airplane takes off and during climb, what is the RELATIVE AIRFLOW?
3). During level flight (cruise with constant altitude), what is the RELATIVE AIRFLOW?
4). During approach to land until touching ground, what is the RELATIVE AIRFLOW?

What is actually that AIRFLOW?

I apologize if there are too many questions. It is actually just one. Just to make sure that you will not confuse to read and I will not get confused to read your explanation as product of unclear question.

Before I post this question, I have search if someone have posted previously. But I didn't find the same question.


texts: Does a LSA or better license count for drone use?

texts: I have a FAA private pilot license. Does that allow me the same flight privileges while flying a drone, as a FAA certificated drone pilot?


texts: What is the relation between pressure and airflow speed above an airfoil?

texts: Does decreased pressure on the top surface of an aerofoil cause high velocity airflow or does the high speed airflow result in decreased pressure?


texts: What is the proper ICAO phraseology to activate a flight plan?

texts:
OK, so you have a flight plan filed (over internet, phone, company or however), go to the aircraft and get in the cockpit. So you call the controller and request IFR or VFR as appropriate.

What is the recommended wording of the request and how it is actually pronounced? Is “IFR” spelled, like “requesting eye-eff-are”, using phonetic alphabet like “requesting India Foxtrot Romeo” or expanded like “requesting instrument flight rules”?
Should you add the destination or other description of the plan? The ATC already has it, but it might serve as a check.
Do you call only when you are almost ready for start up or push back, or earlier in the preflight? And if earlier, do you also add some indication when you will be ready?

I'm asking about both VFR and IFR flight plans.


texts: What is the maximum takeoff weight allowed for a part 103 ultralight?

texts:
What is the max takeoff weight (MTOW) for a part 103 vertical takeoff (VTOL) ultralight?

And is the value peak or continuous limit?


texts: Why can't I build an entire jet engine out of carbon fiber?

texts: I noticed that most jet engines are made out of aluminum or metal components. However, carbon fiber has a melting point of 3500 degrees celcius, way above metal or aluminum. So, can I build an entire jet engine out of carbon fiber?


texts: Why would helicopters not have black boxes?

texts: Is there a legitimate argument against having a black box on helicopters? I'm assuming there must be reasons beyond financial ones?


texts: What were the 20 airspace classes in the US before 1993?

texts:
ICAO adopted the current airspace classification in 1990. The US followed suit in 1993.

But, I found this:

  In case you didn't know, the U.S. had 20 different types of airspace designations prior to 1993. (VATSIM)

Were there really 20 classes?
What were they and their functions?
And if possible, how did they compare with the rest of the world pre-1990 in a general sense?

What I could find was the Oct 1993 issue of Flying Magazine. From which, I couldn't find the 20 classifications, just 7 old names and some changes.

The FAA order 7400.2D from 1993 includes the change, but I can't find the similar order that precedes it. The preceding document is here, but unhelpful.

Also via here we find: Transition Areas, Continental Control Areas, and Control Areas. All three are now under Class E. That brings the total to 10 out of 20.

Thanks to @Pondlife for the FAA document and for checking the AOPA magazine article.


texts: Does a jet engine keep running when it can no longer be controlled from the cockpit?

texts:
On the Qantas Flight 32 incident, the Airbus A380's number two engine suffered from an uncontained engine rotor failure and partially damaged the controls of number one engine as well.

According to Wikipedia, engines one and four entered a 'degraded mode' after the explosion, and number one could not be shut off after landing.

So it seems that in case an engine loses all communication signals from the aircraft's control systems in the cockpit, it could somehow remain operational.  To me that definitely sounds a lot safer compared to shutting down and risking the plane lose all thrust.

So do jet engines, by design, keep producing thrust in case they lose contact with the control systems?


texts:
Birds use their strong breast muscles to flap their wings and give them the thrust to move throught the air and fly. In a way, birds use a swimming motion to get the lift needed to fly. Plane wings have a similar shape as bird wings, but instead of flapping their wings, we use engines to thrust them into the air and create the lift needed to fly. (Source)

Can we design an aircraft which could also "flap" its wings to fly?
Yes, we would need fuel to anyways do that.  But, from a design point of view, is it possible to do that?


texts: Why would lift coefficent change with weight on swept-wing aircraft?

texts: Today I encountered a problem. There is a book saying, "Why does the lift coefficient of a swept-wing airplane decrease with the increase in the weight of the airplane?" I cannot think of the reason. Isn't the lift only coefficient related to the state of the wing?


texts: quadcopters — should the propellers/motors all be at the same height

texts: In quadcopters (or in any other drones), must the propellers/motors all be at the same height, or can there be symmetric height differences (like for eg, two of the motors at the "back" are elevated just a little like by say 5cm or even less... Is that going to make a significant trouble in the drone performance?


texts: Are the total hours of an aircraft based on flight hours or operational hours?

texts: Are the Total Hours and Total Cycles of an aircraft based on the Flight hours or Operational hours of an aircraft?


texts: Where can I find detailed dimensions of an aircraft engine compressor blade?

texts:
I am currently working on the modeling of blade/casing interactions in aircraft engines. The work is carried out in partnership with a company, therefore, there is a limited amount of it that could be published openly.

Are there any OpenSource compressor or turbine blade designs available (e.g. NACA airfoil profiles for wings)? Where could I find detailed dimensions and material properties?

The idea would be to use it for publication purposes, thus displaying relevant characteristics and realistic behaviors, while keeping all the confidential data of the company internally.


texts:
On Wikipedia, a few obscure ex-Soviet airports like Tamchy Airport in Issyk-Kul, Kyrgyzstan list "Russian IATA codes":

  IATA: none (ИКУ), ICAO: UCFL

"ИКУ" being Cyrillic for "IKU", which is not a recognized code according to the official IATA finder.  This Russian site lists "city codes" (Коды городов), but gives no source, and as bonus gives the ICAO code for Иссык-Куль as "UAFR" (which gcmap.com has never heard of).

Where do these codes come from?  And does IATA play any part in maintaining them?


texts:
Reading about 737-900ER take off roll (3000 meters) from another question, I would like to know what this means.

Is it intended that the aircraft needs 3000 meters before it can pitch up to take off or at 3000 meters is has acquired sufficient height and should be airborne?


texts: Why is *vertical* autorotation in a helicopter not recommended?

texts:
Helicopters can autorotate back to earth in case of emergency. The FAA recommends a flight profile similar to the following procedure:

Notice that in section (2) there is forward speed: vertical autorotation is not recommended. Why is that?


texts:
Most (all?) airlines require the use of a stabilized approach, and it is constantly referred to as a safer way to land an airplane.

What are the criteria for an approach to be considered stabilized?

What makes it safer than a "normal" (unstabilized?) approach?


texts: On average, how many overhauls will thrust reversers have in their lifetime?

texts: How many overhauls will a wide body aircraft composite thrust reverser undergo in its life? (not including damage, etc.)


texts: What can I do as a bystander on the ground if I see an aircraft above me that appears to be failing?

texts:
If I'm watching an aircraft fly overhead and it becomes apparent to me that it is failing, what action can I take in response to this incident?

For now I will leave this question generic as to location, but if it becomes necessary to narrow it down I am interested in the US specifically.


texts: How to know that ADS-B position messages are not spaced more then the 1/2 zone limit?

texts:
I am doing some ADS-B compact position reporting (CPR) decoding at the moment and one of the things that is described is;

"1/2 zone limit" from the last successfully decoded message.

I understand the reason behind it but how can we be sure that new message location is in 1/2 zone limit from the last decoded message?

Note : I am talking about local CPR decoding.


texts: Does the yaw damper require manual activation on modern airliners?

texts: Modern commercial aircraft are equipped with yaw dampers. This post explains the feature. Now I was wondering if there is a button to manually activate and deactivate it (e.g., on a Boeing 787) or if the yaw damper is automatically activated when the autopilot is engaged?


texts: Should I report my cured mild PTSD in the FAA medical certification application?

texts:
I am a combat veteran who was diagnosed with moderate Posttraumatic stress disorder (PTSD) after getting out last year. I  decided to seek treatment and, upon reevaluation, am now at a very mild rating for PTSD with no personality disorders, and no use of medications ever. I am not even eligible for disability compensation that is how NOT severe my PTSD is or ever was. I am currently in the process of trying to get my FAA Medical Certificate for a student pilot and the FAA came back wanting these extreme and expensive tests that were never conducted by my psychologist because they were deemed unnecessary. My psychologist is writing the report they requested, but I have a feeling they will dismiss it and cancel/deny my application because I only have my medical records and my psychological report and cannot afford the psychiatric evaluations and the VA cannot do them for me because they are not medically needed.

Now to my question, if they deny it, then I will reapply again, however as I am as close to 'cured' as possible when it comes to PTSD and it does not affect my reactions to stressful situations or anything that could come up in flying (I've been in a helicopter during the healing process so I know), do I just NOT put anything in the mental disorders box? And if so will they hit me back with "hey we know you applied last time with this, so you're a liar"? PTSD is a curable thing and I feel even more normal than before I even joined the military. Thanks for your time.