texts: I just received my private pilot's certificate 2 weeks ago, yay! Earlier today, a fellow at work who has 700ish hours walked in and asked my office-mate-electrical-engineer "why do we still need ammeters, cars did away with them years ago, voltmeters seem mostly enough." He happens to be nearly done building his RV-14a. Office mate and I were at a loss for making a compelling argument for why aircraft still use ammeters. Is it just for redundancy's sake?


texts: How do visiting foreign pilots access Duats or Duat?

texts:
I'm visiting the US and will get my foreign licence verified, but this means that I won't have a US license or medical. I understand that it is a requirement to sign up for Duats and Duat?!

Any idea or suggestion on how else to use it?


texts: Do non-towered airports commonly have ILS?

texts: Is it common, uncommon or rare for a non-towered airport to have ILS (Instrument Landing System) runways? Can a non-towered airport have ILS?


texts: Assuming we have a convergent nozzle I've read that the maximum thrust is achieved just in the moment the nozzle exit -minimum area- is chocked, i.e., the nozzle is adapted in the sense the pressure in the exit area equals the ambient pressure. How can I demostrate this with formulas?


texts: What operations during preflight and pre-takeoff engine run-up cause a change in engine rpm?

texts: In a Cessna 182, during certain preflight check procedures with the engine running, RPM drops. What are these procedures and why does rpm change?


texts: What aircraft looks like a cross between a Cessna and a glider?

texts:
I always like to look at flying machines overhead.  One day I saw something I've never seen before.  It looked like a cross between a Cessna and a glider.  It was powered, but I heard no sound from it (but I might not have anyway due to ambient noise).  The wings were about twice as long and half as wide as a regular Cessna.  Any idea what that was?  It looked like it was built for pure fun.

Updates in response to comments:

It was not a glider; it had a front engine and high wing like a Cessna.  But it was not a Cessna either.  The wings were about twice as long as a Cessna, and about half as wide.  On the other hand, the wings were about half as long as a glider, and twice as wide.

It was almost directly overhead, about 1,000 feet.  I looked intently since I love aviation in all forms and I'd never seen anything like it.

Whatever it was, it looked like it would be a lot of fun.

If it matters, it was near downtown Seattle about 2 years ago.


texts: Could passengers on an airline flight create an out-of-CG situation by moving around the airplane?

texts:
I've often wondered if most passenger airliners have a CG envelope which would allow the CG of the airplane to be pushed outside the limits if enough passengers relocated to the front or back of the airplane.

If they do passengers might be surprised to know that if for some reason a lot of people got up and crammed into the back of the plane it might become uncontrollable.

If this is the case, the mental exercise could help illustrate how important an understanding of weight and balance is. It also highlights the importance of flight attendants as part of the air crew in their need to ultimately exert control over the crowd of passengers if the situation warrants it.

As a bit of background, I once wondered if Flight 93 during the September 11th attacks might have become uncontrollable because the CG shifted when passengers moved around the airplane. Although I once speculated that this could be the case, I am no longer speculating on the subject. I just want to mention that this is the scenario which made me wonder about the answer to the actual question. Since writing the original version of the question I learned about the CVR from Flight 93 and that it was intentionally flown into terrain by the hijackers.


texts: Could a jet engine be made from cast aluminium?

texts: What materials are used to make the high temperature-high pressure bearing parts in a jet engine? I'm asking about the combustion chamber, combustors, nozzle and diffuzers (as in ramjets) rather than turbomachinery. Could cast aluminium or cast steel do the job for a low thrust small model engine?


texts: This might be more of an anecdotal question, but are there any aircraft where under full throttle (with afterburner in worst-case) where the wheels wouldn't provide enough friction against the runway to keep the aircraft from starting to roll (and skidding the locked-up tires)?  Obviously if the runway was iced it would make a difference in friction; I'm more wondering about in normal runway temperatures where it's just rubber on concrete.


texts: Why do airliners pitch up during cruise?

texts:
In my experience as a passenger, when the plane stands at the airport and you enter it, the aisle is pretty much horizontal. (Obviously, I've never flown on a DC-3). After takeoff we pitch sharply upwards (duh!), but even after the captain comes on the PA with "we have now reached our cruise altitude", the aisle continues to point a few degrees upward. Usually it's only at "we're starting our descent into XYZ" that the body returns to a more or less horizontal pitch.

Why is this? I have some hypotheses, but don't know which, if any, of them hold truth.

It's just how the aerodynamics happen to work out. (Unlikely -- it would seem to be a simple engineering matter to attach the wings to the body at an angle such that the right angle of attack for cruise flight corresponded to the body being horizontal).
Pitching the body upwards slightly allows it to generate some lift, free of a proportional increase in drag relative to pushing the cylindrical body straight through the air.
Passenger jets are deliberately designed such that they never need to pitch lower than horizontal in a routine descent, lest passengers might panic and think they're nosediving to their death. (Also unlikely, unless there is really no hidden costs in terms of drag, etc.)
Landings might be more difficult if the plane had to point its nose downwards in order to get closer to the ground -- the nosewheel would hit the runway first. (On the other hand, simply leveling out would count as a flare, so it's not clear to me that's actually a disadvantage).


texts: Are there additional electrical grounding methods besides static wicks?

texts:
Static dischargers have high electrical resistance, and work via corona discharge.

So if I understand correctly, what wicks do is limit the voltage that the aircraft builds up. But as the wick is ionizing the air around, I guess this voltage is rather high.

Do commercial, fixed-wing aircraft need any additional grounding method once on the ground, when the passengers are boarding/unboarding for example?. How it's done?

Related: This question is about grounding for hangar storage, and also explains grounding for refueling operations


texts: How many bird strikes are there per year? Any world-wide statistics?

texts:
Does anyone know where I could find where the highest rates of bird strikes are?

Along the same lines, other wildlife, such as moose or bears on runways?


texts: How to estimate the altitude of an aircraft at a given distance from a runway?

texts: What altitude should a heavy class commercial freighter be at on a descent path 17 nautical miles from a runway? (Say SDF airport)


texts: Why is cloud base estimation taught in Fahrenheit?

texts:
I've seen the formula for estimating cloud base consistently presented using Fahrenheit temperature and dewpoint (for example, see PHAK 12-14; Jeppesen also teaches it this way):
$$
\mathrm{cloud\:base} \approx \frac{(\mathrm{temperature\:°F})-(\mathrm{dewpoint\:°F})}{4.4\mathrm{°F}} \times 1000'
$$
However, a METAR always gives temperature and dewpoint in Celsius, and pretty much everything else in aviation uses Celsius — even lapse rate, which is the basis for this formula, is taught as "2°C per 1000 feet". It seems to me that using °F in this formula invites error, since temperature and dewpoint must first be converted to Fahrenheit before using this formula. If the constant on the bottom of the fraction were $2.4 \mathrm{°C}$ then the formula could be used directly with numbers from the METAR.
Is there a specific reason why this formula is given in °F?


texts: Can someone help me in identifying this plane?


texts: When airport marhall signals have been used for the first time? Wich is the history about these signals? Thank you


texts: How can Ryanair offer flights for a penny?

texts:
Of course, we all know that you're not exactly treated like a rockstar on Ryanair, and their CEO wants to charge us £1 to use the toilet; but still, how can they offer flights for a penny?!

Looking at flights with budget airlines, they usually end up costing more, with taxes etc added on, but I've seen Ryanair offering flights for literally a penny, all in.


texts: Does the Cessna 152 or 172 have emergency door cable releases?

texts: Is there such a thing as an emergency cable release inside the cockpit of 152 or 172, to remove the door hinge pins in an emergency?


texts: How does the efficiency of a turbofan compare between take off speeds and optimal conditions?

texts:
I know turbofans are less efficient than propellers due to accelerating a smaller mass of air faster. So my question here is not comparing turbofans vs other engines, but compare how inefficient is a turbofan operating at take off and low speeds compared to that same turbofan in its optimal conditions?

In other words, how much is the efficiency loss? Are we talking about 5% or about 50%?

Also, why exactly that loss of efficiency happen (again, compared to the same engine at optimal cruise conditions)? Is it just the speed differential between the exhaust and aircraft airspeed, or is it something to do with the compressor/turbine efficiency?


texts: When to use beacon, anti-collision, strobe, logo, and navigation lights?

texts:
During taxi, the taxi lights are used, and I think the landing lights are required to be used up to 10.000 feet for all commercial flights.

However, my question is regarding the abovementioned lights: beacon, anti-collision, strobe, logo, and navigation lights. When are they to be used, and when should they not be used? What is the meaning and purpose of each one?


texts: Why did the F-104 Starfighter have a T-tail?

texts:
The F-104 Starfighter was launched in 1954, nine years after WWII. It had short stubby wings and a T-tail. According to wiki, the short stubby wings caused inertia coupling and the T-tail reduced this.

My question is: is that really the reason why the F-104 had a T-tail? How does that help reduce inertia coupling?

EDIT

@aeroalias answer has many of the reasons for the T-tail. Had edited the question with some additional info, it was suggested to put this in an answer instead.


texts: Can TCAS be used to confirm "traffic in sight"?

texts:
If a pilot is asked to confirm traffic in sight, but they have hard time locating the traffic visually, however, they can see it on the TCAS display.

Can they confirm they have the traffic in sight and are able to maintain visual separation based solely on TCAS?


texts: How can I take off in a straight line if the runway isn't visible ahead?

texts:
In a C152, flying VFR, if you point your nose up you wouldn't be able to see the runway, thus it would be difficult to keep yourself aligned to it.

So once you take off with a C152, do you climb in a fixed climb rate or do you level off at a certain altitude whilst over the runway, and start your climb again once you've reached the threshold of the runway?


texts: Why is the nacelle outlet of the tail engine of the L-1011 Tristar lower than the engine itself?

texts: I've noticed that the nacelle outlet of the Lockheed Tristar is situated below the engine itself. It is at the end of the fuselage. The nacelle outlet of the tail engine of the DC-10 on the other hand, is at the same height as the engine. Why did Lockheed choose to lower the nacelle outlet? Perhaps this picture will help show you guys what I mean.


texts: How does an elevator offload function works in fly by wire flight control systems?

texts:
In some fly by wire systems I found that there is no trim in the traditional sense. I believe it is because the forces that pilot feels on the stick are artificial. I was told that those fly by wire systems has elevator offload functionality that moves H-stab.

Can anyone explain how elevator offload functionality is implemented?
Does the artificial feel system generate force in response to airspeed and vertical acceleration? (like making pilot push harder for every knot/every G away from the trimmed state?)
Is trimming necessary for FBW systems and if so How does the fly by wire system implements the trim?


texts: What happens when all electrical systems in a helicopter fail?

texts:
I was thinking of asking this question at Worldbuilding, because it is for a book I am writing, but I hope this site will fit better. You can migrate this question if you find Worldbuilding more appropriate.

Let's imagine a flying helicopter, something like Eurocopter EC135. What happens if all electric equipment suddenly stops working? The reason of this failure is not important, just imagine all electricity is "gone" without any warning: all screens are black, all lights are gone, all communication is cut, GPS not working anymore etc.

I suppose the main engine is still running, no reason for sudden falling, right? But... is the pilot still able to fly it? Is it probable he would land successfully? Does the helicopter need any electricity to stay flyable?


texts: Why there are nearly no upper wing jetliners?

texts:
Whenever I look at the western airliners. All of their wings are always mounted on the lower part of the fuselage except the Dash 8 series which have turbo props.

But the Soviet jetliners have their wings on the top of their fuselage like the Antonov AN-158

My guess is they are mounted on the bottom because it makes reaching the engines possible and even the Soviet planes are designed to be few meters above the ground to make it easier to access the engines just like the western Dash 8 planes [maybe it's a coincidence because they don't make big airliners and dash 8 planes are small]

Is there an reason why nearly all jetliners have bottom mounted wings?


texts: Is it possible to build 'Contra-rotating' EDF?

texts: Is it possible to design an EDF (Electric Ducted Fan), with two counterrotating blades, that will have more thrust than two separate EDFs with the same blades?


texts: Do airline pilots practice stalls in actual aircraft?

texts:
PPL pilots are taught stall recovery by experiencing it first hand with an instructor.

Do airline pilots intentionally stall an aircraft during training? Or is it all simulator practice because it's too risky?


texts: Why have different departure hall and arrival hall locations?

texts:
For most of the newly built airport terminals I've seen, the arrival halls are located on the lower level and the departure halls are on the upper level.

What is the benefit and disadvantage when:

Departure halls are above arrivals.
Arrival halls are above departures.
Arrivals and departures are on same level but in different places.

How do arrival/departure locations inside the airport impact the placement of airliners at the gates?


texts: Why does pulling the mixture to idle cutoff increase the RPM slightly?

texts: When adjusting fuel control on a reciprocating engine, why is there a slight RPM rise (50-RPM rise) when pulling the mixture control to idle cutoff? Why if more than a 50-RPM rise, carburetor is set too rich?


texts: Can noise from contra-rotating propellers be reduced by having a different number of blades on each propeller?

texts:
Heads up: This came from Wikipedia's page on contra-rotating propellers and it explicitly says citation needed:

  However they can be very noisy ... It is also helpful if the two propellers have a different number of blades (e.g. four blades on the forward propeller and five on the aft).[citation needed]

Any truth to this? Can a variable number of blades per propeller really help reduce noise? If so, how?

(It doesn't explicitly say if it's piston prop or turbo prop. AFAIK, both can be used for contra-rotating props, and I have no idea which one would be more noisy, or if this supposed variable-blade idea will work on one but not the other.)


texts: Why will reducing the boarding time reduce the costs?

texts:
There are quite a number of publications about airplane boarding which all usually begin with something like:

  Boarding is an expensive process that costs so much, that by reducing the boarding time airlines could save a lot of money.

However, none of the publications I've read says explicitly why the costs are reduced. Of course there is at least one obvious reason:

A shorter ground time reduces delays and thus the number of missed connecting flights, leading to fewer liabilities.

Further there is the possibility that a plane can do an additional flight during the day. But if a plane does 5 flights a day and saves 5 minutes per boarding, then the resulting 25 minutes would not suffice (at least in countries with start restrictions over the night).

So therefore the question: What factors play a role in saving money by reducing boarding time?


texts: Are there any non-bureaucratic hurdles preventing more widespread adoption of synthetic vision?

texts:
Occasionally, a flight will encounter bad enough weather that the crew will become disoriented. While tools like a terrain radar, ILS, and GPWS/TAWS do help the pilots regain orientation, they're not universal; some aircraft aren't equipped with terrain radar, ILS only works on approach to runways supporting ILS, and GPWS is pretty coarse and primarily aural, not visual (beyond a flashing warning sign) on most aircraft. This means that there's still a risk of overshooting or undershooting a runway, or even controlled flight into terrain.

Some higher-end private aircraft have started incorporating decked-out glass cockpits which, among others, can include synthetic vision systems -- these can show terrain, glide slopes, and other traditionally VFR elements which can otherwise be invisible during night flying or in poor weather.

I haven't seen high adoption of these kinds of systems even in brand-new airlines, though; is there a technical reason why these aren't being included (or even mandated) above a certain type rating? Is it purely pragmatism while the system becomes more ironed out? Or are the hurdles before adoption purely bureaucratic at this point?


texts: Are “Kennedy Steve’s” various jokes allowed in ATC communications?

texts:
Forgive me if there is an obvious answer to this, but I was just listening to this “Kennedy Steve” playlist, and he seems to joke a lot more than most ground controllers I’ve listened to.

I have three questions about this.

Is it legal for air traffic controllers to joke on the air at all, and definitely this much?
Are Ground controllers held to the same rules regarding communication as Tower, Approach/Departure, or Center?
Is it more serious for a pilot to start joking on ATC, or for a controller to, in terms of consequences?


texts: Do pilots lose their licenses following a gross misdemeanor conviction?

texts: Can you have a conviction for a gross misdemeanor and still keep your private pilot's license?


texts: Could a controller or airport in the US decide to use English-style landing clearances?

texts:
In the U.S., controllers are allowed to clear multiple planes to land on the same runway, with the assumption that the first plane to land will be out of the way by the time the second plane gets there. However, in England (and I think a lot of other places), you're not allowed to clear a plane for landing until it's the very next plane to land and there are no takeoffs or crossings ahead of it.

Could an American controller, or airport as a whole, just decide not to do sequenced clearances? That is, if they need to cross a plane in front of one that's landing, tell the landing plane "Cancel landing clearance but continue approach", then re-clear them to land once the runway is clear?


texts: Where exactly can I find the FAA's UAS pilot training course (ALC-451)?

texts: I'm trying to get my commercial drone operators certificate. I already have a private pilot certificate, so from the FAA website, all I need to do is complete the "Part 107 small Unmanned Aircraft Systems (sUAS) ALC-451" course on faasafety.gov, then file some paperwork. But I can't find the course. Is there a direct link to it?


texts: Why does the B777 have no winglets? Are there any drawbacks to having winglets?

texts: I have googled and noticed that almost every Boeing 777 is not equipped with winglets. Does anybody know the reasons why Boeing did not equip B777s with winglets? Are there any drawbacks to having winglets?


texts: How do GLS avionics plot an entire accurate approach path?

texts:
I'm studying wireless navigation systems, especially GBAS. I have gone through some ICAO documents regarding GBAS. From what I have read, FAS data is included in Message Type 4. Closer examination of FAS data block tells that there is no block ID or sequence number which suggests that FAS data is not sent in chunks.

My question is, how does the on board equipment plot an entire accurate approach path? Since FAS data block has just the coordinates for LTP and FPAP.

I'm not a pilot so my understanding of operational details regarding GLS is pretty basic.


texts: Do pilots adjust the aircraft's flight path to allow for the curvature of the Earth?

texts:
If an airliner is flying at approximately 500-600mph, it seems to me that there would need to be a significant adjustment for altitude so as to not fly off into space.

Wikipedia says that there's an 8 inch drop for every mile because of the Earth's curvature. But, I've never heard of any airliner adjusting for the curvature. Also, shouldn't aircraft have to adjust somehow for the Earth's rotation because it varies depending on the latitude?


texts: Please explain differences between AFM and FCOM manuals?

texts: What are the key differences between AFM and FCOM and where they will be used?


texts: Are there any safety or technical reason airlines do not display flight information to passengers in real-time?

texts:
A newer addition to commercial airliners is seatback screens, that allow the passengers to watch movies, TV, and so forth. On most airlines, there is also a map, that shows you the aircraft's flight path, position, airspeed, and altitude.

I have noticed that the information displayed on the map screen only updates in roughly 15-second intervals. Is there any reason for this? I can't imagine that there would be any bandwidth limitation issue for such a small amount of text data (for example, I can drive a ton of data to my ForeFlight app with my relatively mid-range GA IFD), so I imagine there must be a safety or technical reason for it.


texts: What is the Difference between mogas and avgas?

texts: Could anybody tell me the primary differences between mogas and avgas?


texts: Can you help me to identify a Boeing 727 maintenance task involving a safety risk for a research project?

texts:
I need help identifying a Boeing 727 maintenance task that would be suitable for a research project on improving maintenance instructions.

Ideally, the task should meet the following criteria:
- the task should take about 1 hour to complete in a base maintenance environment;
- the task should have a safety risk that is prone to human error (for example, potential to do an incorrect installation of a component).

This is for a research proposal to improve the quality of maintenance instructions. I have a commercial aviation training school that is interested in participating. They have a 727 which is a type I've never worked on and I don't have access to any of the 727 manuals either.

I'm trying to table several options that I can put to the school. What I have so far is removal/installation of an AC generator or perhaps the generator constant speed drive. Further suggestions would be very much appreciated!


texts: Why are modern regional jet designs shifting towards under wing engines?

texts:
Historically regional jets (eg, MD-95/B717, CRJ-700/900, ERJ-145, etc) have had their engines mounted near the rear of the fuselage.  But, recently, regional jets are increasingly using an under wing configuration (E-170/175, Sukhoi SJ100, Mitsu MRJ700 to name a few.)

A couple related questions:

Why might this configuration be advantageous for small jets as opposed to the rear mounting configuration commonly used before?
If it's advantageous, I assume technical problems are what stopped it from being implemented before.  So what has changed that allows manufacturers to use this configuration now?


texts: Which standard is applicable to the electric power system in civilian US aircraft?

texts:
I am trying to close a gap in my answer to this question:
Are there general accuracy requirements for aircraft power supplies?

There is MIL-STD-704(F) Aircraft Electrical Power Characteristics for military aircraft.

Which standard is applicable to the electrical power system for civilian aircraft under the authority of the FAA?


texts: Which industry started to develop CFD software?

texts:
Which industry first started to develop CFD?
(aviation,car-industry,meterology or maybe someone else)


texts: Why do No Tail Rotor (NOTAR) helicopters use an enclosed variable pitch fan?

texts:
Aerotécnica AC-14 was an early no tail rotor prototype which used the ducted exhaust from the turboshaft to counter the torque of the main rotor. The concept seems simple with few moving parts.

It didn't use a (seemingly complicated) enclosed variable pitch fan driven by the main rotor transmission, neither did it use Coandă effect (even if it may have), like modern NOTAR does.

Why has a much more complicated solution been adopted for modern no tail rotor systems, and why was AC-14 concept abandoned?

(Autorotation yaw behavior may be one safety issue, even if autogyro autorotation procedures are quite safe.)


texts: What is the purpose of the shuttle valve in a Piper Arrow's landing gear system?

texts:
This is the PA-28R-201 landing gear hydraulic system diagram.

I am wondering how this shuttle valve functions.  Research I have done indicates that a shuttle valve blocks one attachment to the valve while allowing another to run through.  Only one side or the other, not both or neither.

In the diagram below, everything beneath the shuttle valve is a closed system (other than the thermal relief).

Clearly, the valve cannot be closed on one side or the other or else the pump would be applying pressure through three pistons to a closed valve at the other end of the loop.

Is this shuttle valve different than what I have read them to be?  Is it perhaps in actuality that both sides are either open at the same time or both are closed at the same time but never one closed while one is open? If one remains closed, how could the pump move fluid through the complete circuit?


texts: Who decides how to "handle" an aircraft, with regards to severity of manoeuvres etc?

texts:
Until Friday I'd flown only with EasyJet and Alitalia. In the last weekend, however, I took two Vueling flights and felt that the way the aircraft manoeuvred during the flight was very different when compared to EasyJet and Alitalia.

Take off seemed more "brutal", and we seemed to rotate much earlier, where the EasyJet or Alitalia flights will use more of the runway.
After take off, the airplanes did a lot of maneuvers during climbing. While EasyJet's planes usually do a variation of "turn, long climb, another turn", the Vuelings' performed a number of turns during climbing.
Landings, from the point of view of turning, are the same (as it should be). But after touchdown...it seemed to me the pilot maintained a higher rollout and taxi speed for much much more time, so that in both cases after the gear touching ground the plane reached the apron in a matter of seconds - and in both case the planes were yawing a lot when completing their landing roll and taxi, compared to the EasyJet or Alitalia flights.

In general the impression was that pilots were piloting in a more "sporty" manner (to use a motoring analogy), if you'll allow me the expression, and other passengers noticed it too.

So, question is: was it really just an impression? And if not, is there some kind of "direction" the airlines give to their pilots in how handle the plane?

Notes:

I'm NOT criticizing in any way the pilots. I know standards are
pretty high and is not the kind of job one can improvise or do
careless; I'm not saying or implying that they did pilot badly.
Airplanes are pretty the same, I've flown with EJ's A319 and A320,
both with winglet fences, and the Vueling's one was a brand new A320
with sharklets.
Air conditions were not extreme. In fact, I usually fly
Easyjet in winter in north Europe (MXP/LGW/CDG) in bad weather
conditions, while the Vueling flights were during clear days between MXP
and BCN.


texts: How does the mechanical linkage of the airspeed indicator convert dynamic pressure to KIAS?

texts:
I understand the underlying principle of an airspeed indicator, ie. that it uses the Pitot-static system to measure the dynamic pressure as the difference between total pressure and static pressure.

Knowing that the dynamic pressure is $p_{d} = \frac{1}{2}\rho u^2,$ any linear variation in the measure will be a linear variation in $u^2$, not in $u$ alone. Yet the airspeed indicator markings are themselves uniformly spaced and still, they show $u$, not $u^2$. Therefore: how does the mechanical linkage convert a linear displacement (variation) in the dynamic pressure measurement $\propto u^2$ into $u$?

That is, how is the square root transformation of the dynamic pressure performed at the clockwork level of the airspeed indicator to obtain the indicated air speed?

My guess is that one of the gearwheels will be responsible for this but I haven't actually been able to find any information on this online.


texts:
When I was a kid, I remember one day the news on TV said that a passenger airplane lost an engine.  It simply fell off the wing to the ground.  Then they showed the plane (which landed safely) and the bent up engine in some field.

1) How could that happen that an engine simply falls off?  How many bolts are holding the engine up?

2) If it sheared off the wing, why didn't it break the wing with it?

3) Are there any special protocol(s) for missing engine v. disabled engine?

In addition to what I saw as a kid, this happened last year


texts: Why didn't Boeing or Douglas make a jet airliner before the British DH Comet?

texts: I was looking at the history of commercial aircraft and was wondering why UK-based De Havilland was the first to produce a jet powered airliner (the DH 106 Comet) when the US had a much bigger civil aviation industry at the time, such as Boeing and Douglas? They only produced their Boeing 707 and DC-8 after the Comet was introduced.


texts: How is a conflict between aircraft with TCAS I and II resolved?

texts: Let's say there are two aircraft in a risk of collision, one of them is equipped with Traffic Collision Avoidance System (TCAS) I so it will get only a Traffic Advisory (TA), however the second one is equipped  with TCAS II, and it will get both TA and Resolution Advisory (RA). What is the procedure to be followed if there is a risk of collision, the TCAS II aircraft must follow the RA, and the TCAS I must follow the ATC instructions or what is the procedure in this case?


texts: How can I be US aircraft maintenance technician?

texts: I have only an airframe-related experience of 8 years without a license, but have logbook, my US citizenship in process, and want to become an aircraft technician. How can I become a US aircraft maintenance technician? I have Pakistani aviation experience in airframe/B1.


texts: Under what circumstances should the pilot not flying intervene without asking for aircraft control?

texts:
The communication between the captain and first officer is of great importance, especially when it comes to agreeing who is the pilot flying. This question asks for the procedures regarding taking/handing over control and this is also a related question.

Neither of these question discuss under what circumstances the pilot not flying should intervene without verbally announcing their control of the aircraft.

Are there defined procedures for this?
Is seniority sufficient to immediately intervene in some situations?
Is it up to the crew to decide before-hand that the captain is allowed to "help" a less experienced first officer?

In this video (at about 1:40), the first officer is landing the plane, and immediately after touch-down the captain intervenes by pushing the stick forward, apparently without being the pilot flying at the moment.

This document is also related, although it focuses on when and how to intervene being the less experienced co-pilot. Key quote:

  "You are damned if you ignore a Captain's mistakes!

  You are damned if you do or say something about them!"


texts: Is this contrail from an airplane or a rocket?

texts:
A relative of mine showed me the following picture that she took on the 11th of April, around 8 to 8:30 pm in the Netherlands somewhere near "Leiden" pretty close to Schiphol airport (unfortunately I do not know the direction she was looking at, or the exact location, nor does she remember).

This relative thinks that what is shown in this picture is a rocket ascending due to the steep vertical incline. I however doubt this and rather believe it is a plane flying towards the photographer. The illusion of it ascending steeply being caused by the shadow of the earth falling close to the "plane" while the distant contrail is still in sunlight due to the height at which a plane flies, creating a fake depth effect.

What makes me doubt my theory however is the (to me seemingly) irregularly shaped contrail at the end which look like the plane did some weird zigzagging (or a very strange wind blowing it like that), and it seemingly "just appearing" out of nowhere

Now we both don't know a lot about airplanes, so I was wondering if by looking at these contrails it is possible to confirm or deny that this is caused by an airplane.

Looking at the flightradar for that moment there appears to only have been one plane in the area, and even that appears to be quite far out. Could this plane possibly have left those contrails?


texts: How can ATC distinguish planes that are stacked up in a holding pattern from each other?

texts:
If I understand holding patterns correctly, several planes stack up vertically, each circulating at its assigned altitude until given permission to exit the pattern and enter an approach for landing.
My question is, don't the vertically stacked airplanes appear to be superimposed on the ATC radar? I am wondering how the ATC can keep them sufficiently separated on the screen so they can track them individually.


texts: How are the Tupolev Tu-95's blades shaped?

texts:
The Tupolev Tu-95 "Bear" seems like an awfully cool piece of innovation with its unusual contra-rotating supersonic-tipped props.  From what I've been reading it sounds like it's been the only mass production airplane to use props at those speeds (there were apparently a handful of American examples as test aircraft but NASA abandoned the project?).

I'm curious what profile of blades they used.  I know there are lots of supersonic-capable airfoil shapes out there, but it's not clear which if any of these were used for the Tu-95 props, or even whether a fixed wing supersonic blade profile is appropriate for a prop.  Any ideas?


texts:
I know that airplanes use rudder to turn, and use elevator for nose up and down.

How do helicopters change their altitude and how do they make turns?


texts: Could an arrow planform be better for a supersonic aircraft than a delta? Why?

texts:
From this review paper
Page 11:

Strut-bracing for the SST allows very significant reductions in both vortex and wave DDL via an extreme arrow configuration and could be favourable to LFC via reduced chord Reynolds number

All right. Low chord=low Reynolds=more laminar flow. But arrow wing=high sweep=less laminar flow.
Another paper says: Page 20:

The friction drag reduction concept is a world-first technical approach that obtains a natural laminar flow wing with a subsonic leading edge at supersonic speed. An ideal pressure distribution is first designed to delay boundary layer transition even on a highly swept wing, then an

The screen shots figures from the paper show the aircraft, an arrow-winged with a high sweep.

Here is an image found on the web.

As you can see, it has a cranked arrow wing with a nearly straight leading edge. This wouldn't even give much vortex lift, if I understand correctly.
(The aircraft shown is NEXST-1 from JAXA)
All of this is claiming that a highly swept wing can achieve laminar flow. Yet that is not what I am commonly told. So, what am I missing?


texts: I recently heard the term QBD which the Aviation Dictionary explains is the fuel endurance in terms of hours. If it is an acronym, what is its expansion? If not, what is it derived from?


texts: Have Eddy current brakes ever been used/tested on an aircraft?

texts:
Eddy current brakes (wiki) --- a.k.a. magnetic brakes --- get quite some attention from train engineers. They are used on Shinkansens, roller coasters, and even (as far as I know) metro trains on Lane C in Prague. They basically consist of a magnet and a rotating disk, where these two never touch. The kinetic energy is converted to heat, as in conventional brakes. While Shinkansens give them up, from what I view it is in favour of recuperating brakes and whence it is irrelevant with respect to aviation.

I wonder whether anyone considered their use in aviation. To me it seems that it could be a good option.


texts: What is the minimum ceiling and visibility limits in Class E airspace?

texts: With the intention of landing, taking off, or entering the traffic pattern at an airport in Class E airspace, what is the minimum ceiling and visibility as a VFR pilot in the USA.


texts: Why are the in-flight refueling probes of French-built fighter aircraft non-retractable?

texts:
French-built fighter aircraft seem to have in-flight refueling probes that are not retractable, as seen from the linked images below. What are the advantages of a non-retractable refueling probe that make it worth the increased drag?

Rafale, and Mirage 2000.


texts: Is there any technical reason that prevents installation of a jet blast deflector at Princess Juliana airport?

texts:
A jet blast deflector (JBD) or blast fence is a safety device that redirects the high energy exhaust from a jet engine to prevent property damage and injury.

Regarding the incident on July 13, 2017 at Princess Juliana Airport, I see no jet blast deflector installed. Is there any technical reason that prevents installation of such a safety device?


texts: What are the differences between an EASA part-66 license and FAA A&P Aircraft Mechanic License?

texts: what is the difference between EASA part-66 license and FAA A&P Aircraft Mechanic License? Are there any reasons for a company or individual to opt for the one or the other or both?


texts: What is an autogyro, and why would I ever want to fly one?

texts:
Autogyros seem to be one of those mythical creatures: we know there are actually a few of them out there and they're supposed to be fun to fly.

What are they really; how do they work? And how do you fly one?


texts: What is the total wing surface area of the A320?

texts:
I was trying to calculate the total area of an A320, and in this link I found the wing area and tail area. But here I read that the wing area is just the 2D projection of the wing. So if I wanted to calculate the total surface of the wing I should consider the wing area (122.4 m) and multiply by two, which would be an approximation.

By doing this, and considering the fuselage to be a cylinder, I get a total area of 847 square meters for an Airbus A320, which is close to the 900 square meters reference I found in this article.

So, is it correct to say that the surface area of a wing is approximately the wing area multiplied by two?


texts: Is the Inspire 1 a good drone starter aircraft?

texts:
First of all, I'm not totally positive that this will be well received here; I did read the related meta, but am unsure. I have also asked the question in support of the new Drone SE.

I'm new to drones, and I've been researching. Would it be a bad idea to start out as a beginner with the Inspire 1 (sort of the cutting edge, top of the line, nicest looking drone out there)?

I read somewhere that with Drones, unlike normal RC aircraft, (and large aircraft perhaps) the higher the price, the easier the flying. I'm worried about whether or not getting a very high end drone as my first one might prove a foolish investment?


texts: What is the date of first use of the TAF format?

texts: Unlike METAR and NOTAM, I cannot find any history on Terminal Aerodrome Forecast (TAF). Any hint as to the age of the format would be appreciated.


texts: In actuator disk theory, why does changing the inertial reference frame work for Bernoulli's equation?

texts: I was reading this website: https://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node86.html, which goes over actuator disk theory, and it discusses using Bernoulli's equation in a frame of reference that moves with the actuator disk.  I don't understand how this works mathematically.  Let's say we're in a stationary reference frame and P0=10, u0=5, and P1 = 15.  If we ignore the 1/2 and rho coefficients, we can find u1: 10 + 5^2 = 15 + u1^2 -> u1=4.47.  Now let's do the same with a moving reference frame that is moving with a speed of 4 toward the oncoming fluid.  Now P0=10, u0=9, and P1=15, so 10 + 9^2 = 15 + u1^2 -> u1 = 8.72.  But, if we add the reference frame velocity to the original answer, we get 8.47.  I'm clearly missing a nuance here, can someone help me to understand?


texts: What is the effect of aft centre of pressure movement on static longitudonal stability?

texts: During studying for my Air Transport Pilot License (ATPL) I encountered a question answer which said that aft center of pressure movement increases longitudinal stability. If this is true, I cannot seem to wrap my head around the concept of why this is so.


texts: Class B and C Airpsace Ring Data in Text

texts:
Class B and Class C airspace has multiple rings where each ring can be a custom polygon shape.

I want to extract following data into text:

the shape of these polygon rings in lat/long (ideally a geoJson object)
distance between the rings and
high / low limit for each ring

Is this data available for free or purchase?


texts: What is the name of the system that replaced stairs for disembarking aircraft?

texts: Back in the day, or in old airports, or airports that have not upgraded their systems, passengers disembarked in aircraft using stairs, through rain and or snow and extreme weather, sometimes having to delay disembarking because of bad weather in turn delaying themselves, the airport and the aircraft schedule. Today there is a new weather proof system where passenger disembark the aircraft and find themselves in the air conditioned airport, devoid of all the unfavorable extremes, devoid of delays.  What is the name of this system and when was it introduced?


texts: What would be the effects of installing pitot tubes on the engine covers?

texts: What are the effects on airspeed measurements, if the pitot tubes were installed right on the engine covers of an aircraft instead of being on the nose.  Would the reading be false? If so, would the reading be underestimated or overestimated and why?


texts: What should I study to understand basics of aircraft construction?

texts:
I'm trying to undestand principles of construction of fixed-wing subsonic aircraft.

I have already read explanation on things such as Neutral Point, Static Margin, etc, but I'd like to know how they are linked together, what are typical values they have and why, what are pros and cons of different schemes, and so on. Some of this can be found here, but I think it would be more sound to learn basics first, and start looking for details afterwards.

A good example of literature (or Internet resource) I seek can be "The Jet Engine" book by Rolls Royce. It explains nature of processes while don't digging too much in formulas.

Thank you!


texts:
How does angle of incidence affect an aircraft's stability?

I've tried searching the web for the simplest answer that makes sense but so far I've come up with nothing as yet.
I know it sounds simple, but I'm still new to this so its pretty hard to grasp my mind around the concept yet.


texts: How can I find the location and coverage of aviation VHF transmitters?

texts:
In the USA, is there a way to find locations of VHF transmitters that are used for air traffic communication, and the frequencies they transmit/receive on? There are some places (Northern Bay Area, CA) where I fly where I have good signal/communication with a Terminal Radar facility, but have trouble contacting area approach in the same area - especially when low (<2000ft AGL). The area is hilly.

I'm interesting in seeing range and altitude support for a given frequency (in a given area).


texts: Why not mount airliner jet engines above the wings?

texts:
It seems that most airliners put the engines below the wings, i.e. the Boeing 7*7 series and the Airbus A3** series. This requires long (heavy) landing gear, and the engines are close to the ground which may cause damage to the engines (ingest debris) or the ground.

Why not mount the engines above the wings? In addition to the shorter (lighter, stronger) landing gear, the plane would be easier to service and embark / disembark. What are the major disadvantages to having the engines above the wings for civilian airliners?

The question "How does the mounting location of a jet engine affect aircraft performance?" addresses the performance issues affecting engine placement but answers do not cover over-wing placement extensively and focus only on performance and not other operational issues or design advantages.


texts: Practice Pans - are there any genuine reasons not to use them?

texts:
I'm a low time PPL.  In my personal opinion, practice pans, perhaps one or two a year, are a good thing.  Practice in a procedure that builds confidence removes one more item from the pucker factor list if it does all go wrong and lets your brain focus on the situation.

The D&D cell are always happy to assist and I know that they welcome it as it gives them practice as much as it does me. They are always excellent and it's comforting to know that they are there if I ever need them for real.

However, I know that many pro pilots do not approve of this.  I am aware that they are often required to monitor guard and that practice pans can be a source of noise but is it really that disturbing?  I've even had that terse "transmitting on guard" broadcast which to me is a) entirely rhetorical and b) great irony.

If something genuine crops up on guard, then of course I'd shut up and continue on my way but are there any genuine reasons for amateurs to not practice?  Surely it's better for all users of the sky to be as good as they can?


texts: What is an FAA Notice? Does it have legal force?

texts: The FAA issues Notices and other non-legislative rules (e.g. Advisory Circulars). These documents are distinct from the laws in Title 14 of the Code of Federal Regulations. What are the differences between them? Do they have legal force?


texts: Can a missile be fired when a fighter jet is inverted?

texts: Is there an attitude limit for firing a missile from a fighter jet? Can the pilots fire them when they're pulling Gs, or inverted?


texts: Is it possible for an indirect (Russian) attitude indicator to work in 3D without tumbling?

texts:
For a reference of direct and indirect attitude indicator, see How is a confusion possible between Western and Russian Attitude Indicators?, and https://www.skybrary.aero/index.php/Western_and_Russian_Artificial_Horizon_Formats.
Direct (Western) attitude indicators can be made to work without tumbling, or even made into a "Navball" that also displays directional information:

See the attitude indicator at the center, Source, and Source.
Or alternatively, look at Kerbal Space Program's navball.
Is the same thing possible with the indirect style indicator?
If one plays DCS, he or she should know that this style of indicator would always tumble when maneuvering pass 90 degrees above horizon, even though the gyro has no gimbal limit.
This is understandable, because otherwise the indicator must display the horizon upside down... or am I missing something?
Is there another way I missed which can get around this issue, or is indirect attitude indicators not capable of representing full 3D orientation, like a navball can?


texts: Can I file IFR DIRECT with a non-WAAS GPS?

texts:
The AIM 1-1-17 2 (a) states:

  Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for
  navigation under IFR must be equipped with an alternate approved and
  operational means of navigation suitable for navigating the proposed
  route of flight. (Examples of alternate navigation equipment include
  VOR or DME/DME/IRU capability). Active monitoring of alternative
  navigation equipment is not required when RAIM is available for
  integrity monitoring. Active monitoring of an alternate means of
  navigation is required when the GPS RAIM capability is lost.

Does this mean that if I have a non-WAAS GPS unit then I have to file only along Victor airways or between VORs? Or can I file DIRECT?


texts: Why is horizontal stabilizer set to 4° up in airbus aircraft for take off?

texts: Why is horizontal stabilizer set to 4° up ( or any other setting other than neutral) in airbus aircraft for take off? Why can't we keep the trim neutral?


texts:
If you're talking about a big puffy cumulus cloud it's pretty obvious. But from where I am right now, looking up I see grey sky from horizon to horizon. But visibility at the surface is good. All nearby metar's are reading 10SM CLR. It's just a tiny bit hazy, but I can clearly see a water tower that is 8 miles from me. But there is no defined cloud layer. It just seems that the haze gets thicker the higher you go. If there was a vfr plane up there at a few thousand feet I'm sure I could see it but I can't see any of the four airliners that FR24 shows are above me.

My question is, when there's no defined cloud layer, what is considered "cloud" and what isn't? If the minima require you to stay 500 feet below clouds, where exactly is that? With metars showing no ceiling how do you know where it is safe to fly and where there might be an ifr flight descending that can't see you?


texts: Often we hear about Cockpit Voice Recorders, but are there video recorders?


texts: How does the FADEC prevent compressor stall during rapidly increasing thrust demand?

texts:
My understanding is that if the demanded thrust is increased rapidly on a jet engine (for example going from nearly idle to TOGA during a go-around), the engine will likely experience a compressor stall: the combustion chamber is demanding a high quantity of air, but the front of the engine is unable to spin up and cope with the demand in such a short period of time.

This is the reason why engines spools up slowly: the FADEC is carefully controlling the amount of fuel increase to prevent a flameout; pilots should anticipate this delayed response compared to a piston engine.

My question is how exactly does the FADEC do this? Which parameters (air temperature / pressure) are being monitored, and what are the signs which the FADEC can detect such that it knows it has reached the limit of fuel increase?

For example is it something like monitor air pressure at X while increasing throttle, if X exceeds a certain value, stop increasing throttle until X drops?


texts: For what program was this Cessna 182 fitted with canards?

texts: I want to see if anyone knows what the heck is going on here. I was doing a flight out in Palo Alto California recently, and during the run up this Cessna 182 pulled in next to us.   It appears to have a canard foreplanes attached near the firewall of the airplane, and it appears to have a movable control surface on it as well. No this is not a Photoshopped image, this is an actual airplane that was sitting right next to us. I’m just curious if anyone here knows of any program using this aircraft and the purpose of the canard foreplanes.  Thanks.


texts: Did Airbus bring back LAF (Load Alleviation Function) on A320s with Sharklets?

texts: I have heard that the A320 no longer has LAF (Load Alleviation Function) except for really old ones, but I also heard that A320s with Sharkelts do have LAF. So is it true that Airbus got rid of LAF on A320s and implemented it back on A320s with Sharklets, if so does anybody know why, because I heard Airbus says they go rid of it because it was not needed, so why would they add it back if they did? I heard it has something to do with that it increases MTOW (Maxium Takeoff Wight).


texts: Why do we not see propellers on swept wings or jet engines on straight wings?

texts:
Why are these configurations not observed often?

The only time I see propellers are on straight wings or on the nose, while jet engines are always on swept wings or the tail. Why?


texts: Where can I get statistics on landing incidents?

texts:
I sometimes have the feeling that Airbus with augmented control are more prone to landing incidents (hard landings and runway excursions) than other models of aircraft with conventional controls.

Is there anywhere I could find data to perhaps back see if this might be correct? Such as a list of all landing incidents in Europe or the United States?


texts: Is there any specific reason why Delta Air Lines doesn't have its own callsign?

texts:
Many airlines have their own callsigns for use over the radio. A British Airways plane is called "Speedbird", US Airways was "Cactus", etc. So why doesn't Delta Air Lines do the same? It would seem to need one a lot more than others, since "Delta" is the NATO Phonetic Alphabet name for "D", so it would seem to present a huge potential for confusion.

Atlanta airport, Delta's headquarters, uses "Dixie" for the letter, specifically to avoid confusion with the airline. It just seems easier and safer to me for the airline to adopt a callsign rather than deviating from the phonetic alphabet.


texts: Why are you required to commit to a full stop landing if reverse thrust is selected?

texts:
According to Airbus:

  ‐ After the flight crew selects reverse thrust, they must perform a full stop landing.

Does it really make sense to have this limitation, and why? What happens if you realise there's not enough space to land, and you've still got adequate speed?


texts: Why isn't the V flight formation being used for commercial purposes?

texts: The V Flight Formationhas been found to be helpful in achieving greater fuel efficiency and range. Though it is currently used mostly for military purposes, what restricts it from being used for commercial purposes?


texts:
FAR 91.205(b)(8) says that you need a manifold pressure gauge for each "altitude engine", whatever that means.

What's an "altitude" engine?


texts: How does a pilot switch from IFR to VFR mid-flight?

texts: I had a pilot tell me that a rude ATC controller was making him fly way off route and through clouds and turbulence. So he switched to VFR and climbed out of the mess and towards the direction he wanted to go. Without getting into who was right or wrong in this particular situation, how does one cancel IFR mid-flight?


texts:
Can anyone tell me which pilot training institute is best for getting CPL in India?

What other things are needed to be done along with CPL in order to become a co-pilot in an airliner?


texts: How can I calculate the C.G height for an Aircraft?

texts:
before I continue I would like to thank you guys beforehand for the help. I am new to this forum and in aviation in general. I am helping my professor to obtain the C.G coordinates in x, y , z for a simulation of a Cessna 172 (we are using Tornado for Matlab). From what Ive read, the C.G in aviation is mostly obtained through the longitudinal axis (x), I assume that the y is centered in most cases, but I am wondering, how can I obtain the height of the C.G, can I use the same method as in the longitudinal axis?

I was also wondering, why is it that for the calculation of the C.G you take into account things such as fuel, passengers, luggage and so on, but not other things like the motor, propeller, fuselage, landing gear, etc.?

Sorry if my questions are a little stupid or obvious. Thank you for your help!


texts: Is there any combination of two airports that are connected via taxiways?

texts:
Are there any 2 (or more) airports that are ground-connected so that e.g. aircraft can taxi between them? Would that be even possible from a definition point of view, having a common area with two airports?

I thought of airport being a facility with an ICAO identifier, but maybe a different definition suits better here?

I could imagine e.g. having an international one and a GA / regional airport being so close together that they were connected at some point. Does anything like that exist?

Update: I'm also curious about airports that are not directly connected in a physical way but e.g. in an operational way: an airside bus takes passengers from the gate in a terminal in airport A and brings them to their flight in airport B or other situations like that.


texts:
When looking at the silhouette of a DC-3, one can clearly see that the wings are swept. This design is from 1935, before the high-speed research work on wing sweep was ever implemented, and the DC-3 was not very fast anyhow.

Leading edge sweep was 14 deg and trailing edge 0 deg, so the quarter chord wing sweep was 10.5 deg, not inconsiderable, and causing some of the ugly stall behaviour associated with wing sweep. A 1938 NACA video of a DC-3 stalling here, a bit lengthy but it illustrates the tip stalling first, then the aileron.

None of the benefits and some of the drawbacks - why did the DC-3 have wing sweep?

Image Source


texts: Have any large aeroplanes been landed — safely and without damage — in locations that they could not be flown away from?

texts: And, what was done with them subsequently?


texts: Which aircraft is shown in this TV show?

texts: Its registration appears to be VH-AES but a search of the Australian database shows it as being a DC-3??


texts: Can I use the autoland mode if the airport is unknown to the FMC database?

texts: Can I use the autoland if I have to land on an airport which is not known to my FMC database? Is it possible to insert the coordinates to get the autoland mode?


texts: How many pilots does an airline hire for each new plane they purchase?

texts: I guess this would depend if the airplane is narrow body or wide body because wide body airplanes make longer trips. Another way to ask this question is what is the ratio of airplanes and pilots in an airline company for wide body and narrow body passenger jets respectively.


texts: Is there a website similar to FlightRadar24, but showing general aviation?

texts:
As far as I am concerned, FlightRadar24 reads out transponder responses.

As most engine driven aircrafts have at least a mode C transponder, is there a site that displays such traffic as well?


texts: How do landing fees work at larger airports?

texts:
Many larger airports (class Bravos) have a landing fee. What's the process for assessing and collecting the fees?

How do these landing fees work with general aviation aircraft?
Where can I find out what the fee will be? Is it published?
How will I be charged the fee? (Pay before leaving the airport, bill sent to my home, etc.)
Is the landing fee a flat rate or is it calculated based on aircraft weight or some other factor?
I've heard that the landing fee is generally waived if you buy a few gallons of (overpriced) gas at an FBO, is that true?

Example scenario: I offer to take a friend up for a scenic flight. He lives very close to a moderately busy class B airport while my home airport and FBO is over an hour away from him. I offer to fly into the class B airport to pick him up and then drop him off at the end of the flight.


texts: Do someone knows a way how to arrange an American(N) registration of aircraft located in Europe? I mean there should be an agency that you can entrust with carrying out an American registration of an aircraft that is in Europe. I am looking for this office.


texts: Does the tailplane have a positive/negative camber?

texts:
I've read that the tailplane produces negative lift, so does that mean it would function like an inverted wing (has negative camber)? The image below is the best illustration I could come up with.

Also, is negative lift and tail down force the same thing?


texts: Looking for techniques to model resistance to roll rotation in a very simple, force-based flight model

texts:
I'm new to flight dynamics programming and am curious to know how people model an aircraft's resistance to rolling in very simple force-based flight models (not CFD, etc.).  For example, after a full deflection of the ailerons, the stick is returned to center and the aircraft will stop rolling.
I assume I should be looking at factors including dynamic pressure, wing area, and a center of pressure for the wing.  I'm just not sure if I should just be modeling the "wing pushing against the air that it is rolling into" or if there are other more significant physical principles at play.
Essentially I am trying to create a model in which I can tune maximum roll rates against an aircraft's tendency to want to stop rolling.
Thanks, and sorry in advance if this is too vague, but any info will certainly be appreciated and will help steer me.


texts: How is Altitude/QNH defined state when passing transition altitude?

texts:
Let's say an airplane is climbing towards transition altitude (TA = 5000 ft), and it has it's altimeter set to QNH = 1030 hPa. The altimeter is a function of pressure and QNH: altitude = altimeter(pressure, QNH). Let's say P is a pressure at TA = 5000 ft when QNH = 1030 hPa (roughly 857.74 hPa) - so P is the pressure when the airplane reaches the transition altitude.
When it reaches TA, the altimeter setting is changed to 1013.25 hPa so the indicated altitude changes as well. With the same P and different QNH, the altimeter now shows roughly 4545.8 ft. Well, this is way below transition level and transition altitude, so the altimeter should be set back to QNH = 1030 hPa. But now it shows 5000 ft again, so let's set it to 1013.25 hPa. The altitude and QNH oscillates, because the input to the altimeter (QNH) is based on it's output (altitude).
The same thing happens on a horizontal edges of airspaces (changing from REG QNH to METAR QNH) and when descending towards transition level.
I assume that pilots change the altimeter setting to "just something". But how should a software calculating the indicated pressure altitude deal with this? The point of the software is to calculate events where QNH should be changed by a pilot. The software runs after the flight and has access to resources such as airspaces, transition altitudes, METARs, GPS and pressure during the flight, and so on.


texts: Are solid-state attitude indicators subject to gimbal lock?

texts:
With all the shiny new glass cockpits it would seem that the days of the spinning mechanical gyro (and associated tumbling due to gimbal lock) should be over: Sparing everyone the boring math it should suffice to say that solid-state gyros can be engineered and built in such a way that gimbal lock is impossible, but I'm not certain that's how they're actually designed.

Do modern AHRS systems with solid-state gyros (or replacement electronic horizons like the RC Allen 2600 series) still suffer from gimbal lock, or do they provide true 3-dimensional freedom?

I'm interested primarily in answers from a light General Aviation standpoint, but answers about electronic gyros on commuter and transport category aircraft would be interesting too.


texts: How the fuel in the wings is managed in case of an engine failure?

texts:
Consider an aircraft has fuel tanks only in wings (No central tank).

Will the fuel for the respective engines will be consumed from the respective wings?

In case of a single engine failure, if the fuel is keep on consumed by the active engine, whereas not consumed in the inactive/damaged engine, will this affect the aerodynamic property of aircraft?


texts: Why do airlines follow these routes between Barcelona and Düsseldorf?

texts:
In the wake of GermanWings' terrible incident of flight 9525, I have noticed that the crash location is quite far from the shortest route connecting the two airports.

I then went on FlightRadar24's website and checked that this is the normal route for this flight (and that there is an alternate one that reaches equally far on the other side):

Other companies that fly the same route (Vueling 1894, Airberlin 8947) follow the same flight paths.

Why is this? What limitations are in place that prevent these aircraft from flying over Lyon (and "nearby" region)?


texts: Why is it assumed on sectionals that the area outside of a 700 AGL Class E (Echo) transition area is Class E starting at 1,200 AGL?

texts:
In this Bold Method article (http://www.boldmethod.com/learn-to-fly/airspace/class-g-airspace/) it is stated that anything beyond the hard lines of this examples 1,200 ft AGL Class E (blue) transition area is Class G (Golf).

So far so good.

However, further down in the article, it is stated that beyond the hard lines of the magenta 700 ft AGL Class E transition area that the airspace is Class G until 1,200 ft AGL at which point it turns into Class E again (think the blue Class E area that exists above this entire area).

Why is it assumed that outside the 700 ft AGL Class E transition area there lies 1,200 ft AGL Class E? It surely isn't represented in the screenshot. Couldn't it just as well be Class G until 14,500 ft AGL?


texts: What is the theoretical maximum speed of a rocket-powered aircraft in the atmosphere?

texts: I read that the scram jet has a theoretical maximum speed of Mach 24. What is the theoretical maximum speed of a rocket-powered aircraft designed to operate in the atmosphere?


texts: If props throw air outwards, why do some prop diagrams show a reduction in airstream diameter behind the prop disc?

texts:
If props throw air outwards, why do some prop diagrams show a reduction in airstream diameter behind the prop disc, or are these velocity vectors?

Diagram showing airflow outwards as shown on nap.edu

Diagram showing reduction of airstream behind prop as shown in Zenith, Flying on your own wings.


texts: Can a runway turnpad be used as a runway holding position?

texts: Can a turnpad also be used as a runway holding position?


texts: Why can’t we perform CONFIG 1+F Takeoff in the following conditions as per the MEL?

texts:
I was reading in one of my company notices that we can’t perform  config 1+f takeoff on the Airbus A320 if we have the following faults.

SFCC SLAT CHANNEL FAULT
ADR 2 FAULT
IR 2 INOPERATIVE

Could someone explain the reasoning behind this?


texts: Why does the DC-10's horizontal stabilizer have such a pronounced dihedral?

texts:
If you look at this picture, you'll see that the horizontal stabilizer has a very pronounced dihedral in comparison to the wings. Could somebody explain in a simple way why? I understand that a dihedral wing makes an aircraft more stable on the roll axis, but why on the horizontal stabilizer, which produces a downforce?

This question is not just about the DC-10, because there are also other planes that are not trijets and have this feature, I just used the DC-10 as an example

See also this schematic:

Image excerpted from original, by Julien.scavini, used under CC BY-SA 3.0


texts: Would increasing rotor disc diameter increase efficiency in a helicopter by reducing disc loading?

texts: Despite the obvious drawbacks of a larger rotor diameter would the reduced disc loading increase efficiency during hover and forward flight?


texts: What is the relation between clouds and radar effectiveness?

texts:
Recently, India's prime minister Narendra Modi commented on how cloudy weather can help a fighter jet  escape from radar. Is there any technical reasoning to back these comments?

Here is the quote in question:

  In the interview by TV channel News Nation on Saturday, PM Modi said,
  "The weather suddenly turned bad, there were clouds... heavy rain.
  There was a doubt about whether we can go in the clouds. During a
  review (of the Balakot plan), by and large the opinion of experts was
  - what if we change the date. I had two issues in mind. One was secrecy... second, I said I am not someone who knows the science. I
  said there is so much cloud and rain. There is a benefit. I have a raw
  wisdom, the clouds can benefit us too. We can escape the radar.
  Everyone was confused. Ultimately I said there are clouds... let's
  proceed."

https://www.ndtv.com/india-news/controversy-over-pm-narendra-modis-cloud-can-help-us-escape-radar-comment-on-balakot-air-strikes-2036402


texts: What do I do with fuel, distance, and time to descend and climb, on nav log?

texts: So I've got my navigation log mostly filled out. All that's left to do is determine fuel to climb and descend. I go to my Archer POH (Pilot Operating Handbook) and use the time, fuel, and distance to climb and descend charts. Got about 1.5 gal for both descent and climb. 8 min and 6 NM for climb, 8 min and 18 NM for descent. What do I do with these numbers?


texts:
I'm currently attempting to assign handling qualities to the A-4D, and I would like to know how to find the term:

$ n / \alpha = \overline{q} \times C_{L\alpha} / (W / S) $

where $C_{L\alpha}$ is the lift-curve slope. I think I could solve for the lift-curve slope by using the value $1/T_{\theta2}$ or $1/T_{P2}$, the phugoid frequency, somehow, but I cannot find that equation.

I'm not given a chart of the change in lift-curve slope per Mach number.


texts: What is the bypass air in a turbofan engine actually for?

texts: I'm planning on building a small model turbofan engine for a bit of fun but I thought I'd better get a better understanding of how they work first. I understand the majority of it at the moment but I'm struggling to see what the bypass air actually does, to my mind it seems like a waste of air and energy if its just going straight out of the engine without compression...could someone explain this to me?


texts: What are the areas of an aircraft that suffers most from G forces?

texts:
i want to ask this time as to "what are the areas of an aircraft that feels or suffers the most from G forces?". i am asking this in terms of structural design and physical limits of the pilot(the position and seat angle) and the plane.
please try not to limit the airplane model to simple light-aircraft,try to expand it near to military Aviation and other else.

if possible, please try not to use high-falutin words since i'm having a hard time with words in English.

If you can not understand this clearly, i am sorry for my poor English and Grammar, and also i want to elaborate more, but i can't translate it properly at the moment.


texts: What is the shiny stripe around the aft wing–body fairing on an A380?

texts:
Source: planespotters.net: 1, 2

Regardless of the airline, that part is always unpainted, and in the right conditions, it looks shiny. From below the plane, it wraps around the wing–body fairing.
Is it a sensor or indicator of some kind? Like for stresses? There must be a reason it's never painted over. From the operating manual I ruled out it's an antenna.


texts: What happens when flying on a Victor airway but through a class B or C airspace?

texts: I think it´s a very simple doubt but also very important, and i can´t find the answer. If you are flying on a Federal Airway that at some point cross a class B airspace (for example)...do you need authorization or can you keep flying without one?


texts: If an aircraft does not have an FDR, must one be installed to comply with Flight Data Monitoring requirements in EASA countries?

texts:
Flight Data Monitoring (FDM), which analyzes FDR data to accomplish things like ensuring that pilots are following SOP's, is a requirement for EASA's Third Country Operators (TCO) certification, however certain (older) aircraft do not seem to require an FDR.

Does this effectively change the requirement so that an FDR must be installed in an aircraft in order to accomplish FDM or is there an exception for FDM as well?  I have been unable to find anything specifically addressing this.


texts: What does the area around the fan blades in the engine nacelle contain?

texts:
I was intrigued to find this picture below. There was so much space around the engine. So what is inside of that extra space? Or is it just a hollow casing?

Image Source

Details about the picture as provided in the image source:

  [Last Year] A Southwest Airlines Co. flight landed safely Saturday
  morning following a major malfunction of one of its two engines during
  a flight across the Southeastern U.S.

  The Boeing Co. 737-700 was flying from New Orleans to Orlando early
  Saturday operating as flight 3472 when it suffered the failure,
  causing the jet to quickly divert to Pensacola International Airport
  in northern Florida at 9:40 a.m. CDT, according to a statement from
  the airline.

  A Southwest spokesman said its initial reports indicated no injuries
  were reported among the 99 passengers and five crew aboard.


texts: How do I determine the diameter of my propeller at high altitudes?

texts: I'm designing a electrically propulsed HALE UAS and I need to find the diameter of my propeller to find my thrust. Is there an equation for propeller diameter that doesn't rely on knowing my thrust or velocity. In particular an equation that is concerned with relative air density as this is meant to be optimum at high altitude cruise conditions.


texts: What is the spacing of obstacle lights on towers?

texts: Radio antennas and other tall buildings have lights so pilots don't fly into them, especially at night. Is there a fixed spacing so you can determine the height of the tower by counting the lights?


texts: What causes an airplane to rhythmically bounce during taxiing?

texts:
Some time ago, I was on a commercial flight and while the airplane was taxiing around, there was this rhythmic bouncing. Here is a video I made of the takeoff. You can notice the bouncing at the taxi and takeoff roll of the video. What causes that rhythmic bouncing? Is it a result of uneven wear on the tires?

For the sake of anyone who wants to know in case it helps, the airplane was a Boeing 757-200.


texts: Which refers to CFI renewal based on pass rate, "activities" or "duties and responsibilities"?

texts:
It's that time again, gotta re-up my CFI.

I always forget when I'm filling out IACRA whether CFI renewals (in the United States) based on student pass rate percentage are considered "activites" or "duties and responsibilities".

Which of the two, "duties and responsibilites" or "activities" is the appropriate choice when submitting an IACRA application for a CFI renewal based on pass rate?


texts: What is the limit between lower and higher airways in VFR?

texts:
On skyvector you see "World high", "world low" and the VFR map.

VFR is always under the clouds, correct?
But how high do you have to be to follow the high/upper and how high for the low/lower airways?


texts: Is there a KPI to measure average hours flown?

texts:
I am working on a report for a small charter airline and I want to set a key performance indicator (KPI) to measure average hours flown.

Is there a practice in aviation field to consider optimum flight hours for an airplane? An arbitrary example: Let's say I have a Boeing 767 and I want to consider if that particular model is profitable (I know it depends on payload, routes, and many other things), does it have to make an average 300 hours per month?

Is there such thing in aviation?


texts: Which airplanes are required to have a Flight Data Recorder in Europe?

texts:
I know that not all aircraft are required to have a Flight Data Recorder (FDR) in Europe (for instance, a small single-engine airplane doesn't need one), but many are, and depending on the age of the aircraft different types may be required.

I've done some searching but am much more familiar with FAA rules and can't seem to find even the right place to look for the "official" answer.

When is an FDR required to fly to Europe in a foreign registered aircraft (FAA if it matters)? I am curious about the actual EASA FDR regulations which cover all aircraft (both private and commercial).


texts: How would a detachable cabin module work?

texts:
Ars Technica recently reported that Airbus filed a patent for a detachable cabin module that would speed loading and unloading of passengers (otherwise known as self-loading freight).

This does seem like it might improve turnaround time since passengers are rather slow to self-load and self-unload. That's not my question (which is in fact an earlier question).

My question is that I had always imagined the strength of an airframe was due to its long cylindrical shape. This is both in terms of it as a pressurized tube as well as lateral strength from bending forces. The detachable cabin module would seem to defeat all of these advantages. Am I correct in this understanding? Are there ways that the Airbus patent mitigates them?


texts: Why has Boeing used mini winglets on the 737-200?

texts:
I found mini winglets just in B 737-200. What's the differences between mini winglets and the blended ones which Boeing uses in more recent versions?
(picture source)


texts: What is the difference between a weapons training aircraft and an actual combat aircraft?

texts:
From the Wikipedia page on the Northrop T-38 Talon:

  Most T-38s built were of the T-38A variant, but the USAF also had a
  small number of aircraft converted for weapons training (designated
  AT-38B), which were fitted with a gunsight and could carry a gunpod,
  rockets, or bombs on a centerline pylon. In 2015, 504 T-38s were still
  operational with the USAF, with many more in operation around the
  world.

What, if any, is the difference between these weapons training capable T-38B and an actual combat aircraft? Is there anything missing (intentionally or otherwise) on a T-38B that would render it ineffective for actual combat, or is this term "weapons training" merely a term used to describe a trainer aircraft? A trainer, due to its age and ineffectiveness against modern aircraft?

Could it be fair to compare some variants of the F-5 against the T-38B? I'd be interested to know the difference, since the F-5 is undoubtedly an actual combat aircraft and not a trainer.


texts: Sorry if this question is too stupid, but I wonder what would happen if a passenger on the first row just behind the cockpit (ie. on a 737) starts screaming "GO AROUND" when the plane is about to touch down. Can it confuse the pilots?


texts: Why aren't there more stringent checks for switching off electronic devices during takeoff-landing?

texts:
I understand from discussions such as these, that it is crucial that to avoid electronic interference with flight instruments, all electronic devices should be shut off during takeoff and landing. And yet, in my experience, there are always rebels getting away with brazenly keeping their instruments on.

My question is, given the critical nature of possible interference (tiny probability but catastrophic consequences), why aren't airlines looking at more stringent measures than a routine announcement/request by the pilot? For example manual checks, frisking?


texts: What is this single-engine low-wing propeller plane?

texts: I found this picture in an article about constant speed propellers, but there was no reference to the type of aircraft. The Flickr account that first posted the image doesn't exist anymore. I did some research myself, I thought it could be a Cessna or a Beechcraft, but I don't know much about it and none of the models I found was a perfect match.


texts: How to read the Appleman chart to predict contrail formation?

texts:
I stumbled upon the Appleman-chart, that makes it possible to predict the formation of contrails.

How do I use this chart?


texts: Should I monitor the emergency frequency (121.5 Mhz) at all times?

texts:
When flying on a plane with two or more radios, should I set the second radio to 121.5 at all times? (Assume I'm not using it to listen on other frequencies)

I've heard that sometimes when an intruder penetrates restricted airspace, the military will broadcast on this frequency in an attempt to communicate with that aircraft. Is this a good way to avoid me getting shot?

What about monitoring in case someone around me has an emergency?

Is there a difference in general aviation vs commercial airlines?

EDIT: I'm asking about whether this is a good idea, not about regulations.


texts:
In moto racing, they use tire warmer to keep tires hot when the tire is not running.

In particular weather conditions (e.g. heavy snow), aircraft require de-icing operation after staying parked for few tenth of minutes.

Do any device to protect the wings and other parts of the aircraft requiring to be free from ice before take off from icing and possibly keeping those parts above icing temperature exist? It could save some deicing time (and de-icing fluid) by reducing the amount of ice accumulated while the aircraft is on the ground.

EDIT: When asking the question, I was thinking of airliners between two legs in winter in Canada (with jetbridge connected, only few tenth of minutes before next scheduled leg, international airport ground support available,... and snow and icing conditions). I don't think the question should be restricited to this case, but it should take it into account.


texts: What are heat detection sensors and how can they cause a speed error?

texts:
From this news article on Saratov Airlines Flight 703:

  A report handed down by Russian investigators has blamed human error for the crash of Saratov flight 703, saying the pilots didn’t switch on the heat detection sensors on the plane.

Heat detection sensors sounds wrong as cause of de-icing failure.

Is it a bad translation of the sensor's name? What would be the correct name? Else please explain how the failure to turn on a heat detection sensor cause icing speed error detection.


texts: What is the maximum angle F-16 can turn in x seconds flying at corner speed?

texts: How can one calculate the maximum turning angle F-16 can turn in x second flying at corner speed. Is it changed with height or weight?


texts: How do we use the runway condition assessment matrix?

texts:
Starting on October 1st, 2016 the FAA is moving away from providing Mu values for runway friction reports to a new format showing contamination type and depth for each third of the runway.  Along with the report is a code X/X/X showing runway condition codes for each third of the runway.

How do we, as pilots, use the field condition NOTAMs in calculating takeoff and landing performance?


texts: What is the black pod starboard of the front landing gear on this F-16-I? At first I thought that it was a laser finder, but upon closer inspection it seems to resemble some type of short cannon. What might it be?


texts: How many smoke detectors does the A340 cargo deck have, and how are they wired?

texts:
I am a student of Aerospace Engineering, currently I am one year away from completing my degree. For my Electric Routing class I was asked to recreate in Catia the fire system in the cargo bay of an airplane and obviously justify why I made the decisions, for now I only have to decide which model I'm going to work with, its specifications, etc.

Looking for information on the internet, I decided that I will work with the Airbus A340 Lower Deck Cargo Compartment Class C. Doing a little research I understood that when there is a fire in this bay, from the cockpit the area is sealed and a percentage of Halon is released 1301.

But 2 questions arose that I would like to know:

How many and what type of fire sensors does this family of aircraft use (the type or model would be of great help)?
Does anyone know how this system is "wired" in general? I mean, in series, in parallel, which is better? How does the smoke sensor connect to Halon pumps?

This is information that I do not known where to find and I do not know if it is classified by the company and I need it to do my Catia model using the electronic Harness Discipline. For now I will be dedicated to modeling the part of my fuselage with the low cargo bay.

P.S: If you know of any regulations that I could read to better understand this topic, I would greatly appreciate it.


texts: What does the FAA consider to be "good moral character"?

texts:
Per 14 CFR 61.153(c) candidates for an ATP license must "be of good moral character".

What does that actually mean and how does an examiner or the FAA verify it?


texts: What are the requirements of ferrying a spare engine?

texts:
It was not uncommon in the 60s and 70s to have B747 ferrying a spare engine.

(source: Australian Aviation)

Was that allowed only on aircraft specifically designed with a pod, or was that possible to add the equipment on any B747. What is the regulation applicable? (in the US for instance).

Additional question: is this still commonly used today in civil aviation?


texts: Which FAA regulations apply to the Stratolaunch?

texts:
(Image source)

Which FAA regulations apply to the Stratolaunch being built by Vulcan Aerospace and Scaled Composites?

Do they follow the same regulations for the type cert, production and CofA (Certificate of Airworthiness) just like a commercial airplane built by Boeing?


texts: What is the typical reaction time for most pilots?

texts:
I'm doing a manned aircraft design and make it easy to fly by making it hard to enter a pilot induced oscillation (PIO). I got a range of natural oscillation frequencies for my design in pitch, roll, and yaw, and now I'm trying to see if the period of these frequencies fall close or far away from most people's reaction time. I searched on Google, but only got data on twitch time, which doesn't seem applicable for an aircraft where some muscle power will be needed, hence my asking this question.

My reasoning is that if it falls an order of magnitude below or above the reaction time of most pilots, the aircraft will be easy to fly (as long as it doesn't go through extreme high G maneuvers). An additional question I have related to this is, how can one design an aircraft to make it difficult for pilots to enter PIO's?


texts: What is the procedure following a near miss?

texts:
This is a follow-up to this question - in particular, to this video posted in MichaelK's answer.

What would be the correct procedure for the pilot to follow in this situation?  (That is, after a near miss).  Should they report the incident to ATC immediately, even though the incident is over?  If there are differences in the procedure depending on jurisdiction, what would it be in the USA and the UK?


texts: Why do the aircraft made by the Soviet Union have fans in their cockpits?

texts:
Surely the countries which were a part of the Soviet Union were not so hot then why are there fans in their cockpits? e.g. TU-134

or IL-76

or AN-124


texts: Why was there no issue with the Tu-144 flying above land?

texts: The Concorde didn't fly supersonically above land, it only could above the ocean. The Tu-144 however flew between Moscow and Almaty, so entirely above land; why did it fly like this? Didn't it have a that loud sonic boom? If no, why not? If it had, why did it fly above land anyway while the Concorde refused to go supersonic above land?


texts: Is there a good reason why modern airliners can't have conventional landing gears (vs. tricycle landing gears)?

texts:
By "good reason", I mean a reason that we definitely cannot overcome with reasonable changes in aircraft design, control laws or procedures.

As possible benefits of this I see a much smaller (= lighter) tail landing-gear than the nose landing-gear. Also, an opportunity to reduce tail-strike margins (=increase incidence, reduce landing speed). And of course there is all that space at the front of the fuselage that is freed for other uses (systems, cargo, stairs,...?)

One drawback is of course passenger comfort. But passengers already experience high pitch angles during climb, and we could imagine to have the tail of the aircraft raised up (on a stand?) for boarding/deboarding. Also the APU has be moved (but I don't think this is impossible).


texts: Can a weather forecast tell me if airplanes will leave long contrails?

texts:
Training 7 ball and 5 club juggling requires me to look up into the sky for durations of up to one minute. Frequently, this is very taxing on my eyes and, frustratingly, requires me to wear sunglasses.

Certain atmospheric conditions are much easier on my eyes. In these conditions, the sky is a very deep blue and I can train juggling without sunglasses, even during mid-day. Atmospheric conditions that have good visibility for juggling almost always cause airplanes to leave extremely long contrails.

The Appleman chart shows that contrails form at relatively low temperatures, low relative humidity, and high pressures. Are predictions of these temperatures and pressures available? This information would be helpful in scheduling my juggling training sessions.


texts: Does a CFI have to be a CFII to fly with a student in IMC?

texts:
A CFI wants to fly with a student under the following conditions:

CFI has ASEL pilot cert with Instrument Rating
CFI has ASEL Instructor cert with NO Instrument Rating
CFI is current in all regards
Flight will be IMC
The Training will not count toward a rating
Will be logged with dual given and actual intruments


texts: What does “to the numbers” mean in landing clearance?

texts: Last night I was left downwind, abeam the tower, on my second circuit of the pattern. The controller said “helicopter xyz, cleared for the option runway 24, to the numbers”. I already had been given a restriction to stay east of rwy 18; as there was an airplane in right traffic there. What is the significance of “to the numbers” in this clearance? Is he just telling me not to land long?


texts:
Why does the ICAO alphabet use "Charlie" for C? Specifically, why choose "Charlie", which has a "Ch" sound, rather than a word with the hard "C" such as "Carl"?

A cursory Googling turns up nothing.


texts: Does airspeed come into play with vertical speed, in terms of who will reach the ground first?

texts: So let’s say there’s two aircraft, which are the same, and both are cruising at 28,000FT, the only difference is one plane is doing 260 knots and the other is doing 280 knots. If they both pitched down reaching a vertical speed of -15,000FT/Min at the same exact time, would the aircraft going 280 knots still hit the ground first despite sharing a vertical speed the entire time??


texts: How can I learn air traffic control as a high-schooler?

texts: I really love aviation and I'm thinking about going for a career in air traffic control, but I can't find anything on the web that will help me learn all about it and how to perform basic operations. Is there anything on the web that I could use?


texts: When is a CFII required to provide instrument training?

texts:
61.195(c) states:

  (c)Instrument rating. A flight instructor may conduct instrument
  training for the issuance of an instrument rating, a type rating not
  limited to VFR, or the instrument training required for commercial
  pilot and airline transport pilot certificates if the following
  requirements are met:

  (1) Except as provided in paragraph (c)(2) of this section, the flight
  instructor must hold an instrument rating appropriate to the aircraft
  used for the instrument training on his or her flight instructor
  certificate, [...]

So as a CFI with a current instrument rating (but not yet a CFII) it appears I can provide instrument training to students working toward their Instrument Rating. I'm trying to find what limitations to this there are - what regs state when training must be from a CFII?

61.65 - Instrument rating requirements (d)(2) states:

  (2) Forty hours of actual or simulated instrument time in the areas of
  operation listed in paragraph (c) of this section, of which 15 hours
  must have been received from an authorized instructor who holds an
  instrument-airplane rating, [...]

Throughout 61.65 it consistently states only "authorized instructor" but there is no definition for "authorized instructor" except only as in 61.1(b) which reads:

  Authorized instructor means— (i) A person who holds a ground
  instructor certificate issued under part 61 of this chapter and is in
  compliance with §61.217, when conducting ground training in accordance
  with the privileges and limitations of his or her ground instructor
  certificate; (ii) A person who holds a flight instructor certificate
  issued under part 61 of this chapter and is in compliance with
  §61.197, when conducting ground training or flight training in
  accordance with the privileges and limitations of his or her flight
  instructor certificate; or [...]

61.197 is only Renewal requirements for flight instructor certification.
So by all this, it seems to me that as a CFI with an instrument rating I'm authorized to provide instrument training. There's definitely something missing here and after hours of digging through regs I just can't find any clearer definitions on this. Can anyone help provide some guidance on where it's defined as to when a CFII is required? Thanks in advance.


texts: Does opening of emergency doors over wings, lead to automatic lowering of the aircraft's wings?

texts: When the emergency doors over the wings are opened do the wings automatically lower themselves, to allow passengers to slide and reach the ground? Or does the pilot have to do it from the cockpit?


texts: I know we have electric cars already. But in the future we’ll eventually have to use something cleaner than gasoline and gasoline is running out! So is it possible to have a battery powered turbofan plane?


texts: Testing control surfaces pre flight; what feedback does pilot recieve?

texts:
During taxi / pre-take off I see a lot of commercial airliners test the deflections of their various control surfaces like the rudder, ailerons etc.

What's the feedback received in this operation i.e. The pilots themselves cannot visually verify the full deflections achieved on command, right? Unlike on (say) a carrier etc where there's a spotter on the ground to confirm.

Just curious, what is the failure mode to be revealed in this sort of test. Is there some sort of internal avionics indicator that would tell the flight crew if the control surface was not reacting to the inputs as expected?


texts: What is the highest indicated airspeed ever achieved in a traditional aircraft?

texts:
It is fairly well known that the SR-71 holds the record for highest speed for a traditional aircraft (not a rocket/able to land and takeoff under its own power). However since the SR-71 flies much higher than other aircraft its indicated airspeed is comparatively low.

I was wondering what the fastest indicated airspeed achieved is and by which aircraft?


texts: Why are so few heliports depicted on sectionals?

texts:
Pretty much every aerodrome, from an international airport to a private grass strip is depicted on a sectional chart. But there are few or no heliports shown. Why is this? Do helicopters have a separate sectional chart? It seems that even for a fixed wing pilot they would be useful as easily recognizable landmarks.

Just as a caveat, I don't have any actual paper sectionals. I am referring to what is shown at vfrmap.com. I have always presumed that their site is a good representation of the official charts, but it's possible there are things not shown online that are on the actual sectionals.


texts: How to calculate the power required during transition from VTOL to fixed wing?

texts:
In a VTOL, I have calculated the power required for take off and cruise which was not difficult at all. Between take off and cruise, there is a phase where the VTOL has to transition by tilting the rotors from 0 to 90 deg. I am finding it hard to calculate the power required for this transition. I feel this is very important because it consumes more power than take off since it is creating lift (hasn't reached the minimum velocity for the lift requirement) for balancing weight and also needs to provide thrust for forward motion.
Given to me are:

Rotor parameters

number of rotors
Rotor diameter
rpm
number of blades

Fixed wing parameters

span and chord (rectangular wing)
lift and drag coefficients

What are the factors considered to calculate the power required for transition?
Please note: Make as many assumptions/approximation as you like. I just want a simple formula for a basic understanding.

The VTOL is a tilt rotor type with ducted fans


texts: If I was in an elevator in a sky-scraper and the cable broke, I would free fall and feel weightless until hitting the ground. When I cause a stall on an airplane (power-ff) and the wings stop producing lift, why doesn't the same effect occur?


texts: Why building a stopway instead of just building a longer runway?

texts:
I don't get the point of building a stopway. If you have the space to build a stopway, you could just extend the length of the runway.

Why are stopways necessary?


texts: Is it true that there are VOR/DME and/or TACAN stations in the oceans?

texts: Are there any VORs placed in the oceans for navigation. Is it true that VORs or TACANs are placed on ships to help oceanic flights, for example flights across the Atlantic?


texts: To use the equipment suffix "G", does the GPS have to be certified for IFR?

texts: To use the equipment suffix "G", does the GPS have to be certified for IFR flight?