texts: Is there a way to prevent (not relieve) the hotspot caused by wearing a headset for long periods of time?

texts:
About a year ago, I bought myself a Bose A20.  Within two weeks, I had returned it.

I will be the first to say that the noise reduction for the A20 was fantastic.  The headset was amazingly light, and clarity was superb.  The reason I returned it was because after wearing it for an hour or two, I would start feeling a sharp pain on the top of my head, where the headset rested.  I'm not the only one to have this happen:

  Unfortunately, I have decided to return these headsets in the 30 day trial period. After the first week, these headsets started to "hotspot" the top center of my head and became uncomfortable after several straight hours of continuous flying. The sound quality was excellent but it came down to a comfort issue. There were a few annoying things.

Here's another...

  On one trip the airplane was equipped with a Bose headset and I thought I would let my wife use it. After 1 hour her head had a bad hotspot and she made me switch. After 30 minutes wearing the Bose I too had a hotspot.

And a quote from the A20 owners manual:

  During a long flight, you may feel a slight pressure point, which can be relieved by adjusting the headband position. Your experience with using the headset will help establish a sense of how it should sound and feel.

I wanted so badly to like that headset (in fact, I still do).  My faithful David Clark will be heading back to the factory for repair soon, and I'm willing to give the A20 another chance, if there's a way to keep that top-of-head hotspot from forming.

Is there a way to prevent (not relieve) the hotspot caused by wearing a Bose A20 for long periods of time?


texts: Why are the B-52 thrust levers advanced inside-out?

texts:
As I understand, the standard procedure for advancing the throttle (for take-off) is as follows:

Advance throttle to desired engine input & output (N1 & N2)
Release brakes
Gradually increase the throttle to maximum
Throughout steps 1-3 either the pilot or the co-pilot control the throttle but not both

However, in this video of a B-52 we see a rather strange way of controlling the throttle. Starting at 0:44 the pilot and co-pilot take turns advancing the throttle in an inside-out manner. What is the reason behind this? Is there really a standard procedure for advancing throttle? Or does it vary based on the aircraft?


texts: Does EASA have access to medical records outside of the EU?

texts: When registering for the Class 1 Part-MED Medical Certificate can/will the EASA have access to your medical records that's outside of the EU?


texts: What effect does wing loading (high and low) have on aircraft performance?

texts:
I've read that stalling speed is partly determined by wing loading. Correct me of I'm wrong - "Aircraft with high loading have more weight relative to their wing area hence the stall speed is increased (as the requirement for lift is increased)".

Also I've read that "faster aircraft have higher wing loading". I didn't quiet understand that statement.

And is wing loading weight/wing area, or mass/wing area?


texts: Why does the MiG-25 have silver-coated panels?

texts:
This is about the Mig-25. This documentary on youtube, @10:03, says:

  Special insulating panels had to be fitted to protect the area around the engines from overheating. The panels were silver-coated. Five kilograms of silver were used in their manufacture.

My question is, why? What does silver-coating do exactly? AFAIK you still need some kind of cooling, either air or liquid, or else the heat flux will steadily raise the temperature to the failing point.

Wikipedia lists the thermal conductivity for silver and copper as 429 W/(m·K) and 401 W/(m·K) respectively. It is only a slight difference and I can't imagine why you would absolutely need that slight difference for a massive increase in cost. Plus I'm pretty sure silver (and gold) are a lot easier to melt than copper.

The only "special" thing about silver, that I know, is that it's highly reflective and therefore is used in the mirrors of superindustrial strength telescopes. I cannot imagine you would need that inside an engine, as virtually all the heat comes from conduction via the hot engine gasses, not radiation.

Edit: The silver could be part of some silver alloy. It would still have to be a coating of this alloy.


texts: Can the thrust of a turbofan be increased by increasing bypass ratio?

texts: I read that the CFM56 is based upon the F101.  Id on't know how true that is, but it generated the following question:  If a larger fan is fitted to a low bypass turbofan, would dry thrust be increased?  Or is it the same amount of thrust produced with less fuel consumption?  That is what I was told on another message board but it doesn't seem to make sense.  Assuming that the proper size turbine is fitted, the same turbine airflow should be turned into more thrust with a larger fan.  Which is correct?


texts: Why was blue hydraulic system chosen for RAT?

texts:
Q1. Why is blue hydraulic system chosen for RAT out of the three.
Q2. If in case of hydraulic emmergency if I push RAT switch on Emer Elec pannel what will happen


texts: What are the forces present in a coordinated turn?

texts:
During straight and level flight, coordinated flight is assumed when there is no net lateral force (no slip or no skid). But this concept totally breaks down when it comes to turning, in a co-ordinated or unco-ordinated turn; there will always be a net lateral force due to centripetal force provided by the horizontal component of the lift force. The centrifugal force (inertial force) found in the books, in an attempt to explain it doesn't make sense to me as the centrifugal force is an imaginary force. So how is co-ordinated flight achieved in term of the forces?
Thanks in advance.


texts: What is "temporary flight plan" in A320 MCDU?

texts: I have been reading FCOM to undestand how MCDU works, there are severel mentions about "temporary flight plan". Does anyone knows what it is?


texts: Why are primary and supportive instruments in instrument flying different depending on the phase of flight?

texts:
For example, in straight-and-level flight, the power's primary instrument is the Air Speed Indicator (ASI), and the supportive are the engine instruments.

In another example, straight constant-airspeed climb, the primary are engine instruments, and the supportive is the ASI.

Why does the primary instrument change?


texts: Why was the experimental MiG 1.44 so similar to the experimental TKF-90?

texts:
Why was the MiG 1.44 so similar to the MBB TKF-90? (for some information on the TKF-90 you have to scroll down this question, it is the only one source I knew about this particular plane)

Here is the MiG 1.44:

(source)

Here is the TKF-90

(source)

For me, these two aircraft are nearly unrecognizable. They were adversaries in those times, not partners. Has that similarity arised only because of the similar expectations from these airplanes?


texts: Are customs stops required for private flights within the Schengen Area?

texts:
I would like to make a VFR flight from Switzerland to Germany and Germany to France and then France to Switzerland.

For the first step: Switzerland to Germany I know that I have to fill a custom form AND a flight plan while taking off and landing on an airport with custom services. The same for France to Germany.

HOWEVER from Germany to France is this rule applicable (note that the plane is registered in Switzerland)? I cannot find an official website?


texts: If an aircraft has two altimeters what is the allowed difference between them?

texts:
If an Altimeter must be within +/- 75 of known field elevation, and the aircraft has two altimeters, one could be +74 while the other could be -74 and both would be within 75 of known field elevation, but 148ft apart from each other.
I've heard some people say the two altimeters must be within 75 feet of each other, but if this is the case, then the first rule can't be correct.
If ALT1 was -74ft from field elevation and ALT2 was -148ft, then they would be within 75ft of each other, but it would violate the first rule as ALT2 would be -148ft from known field elevation.
It has to be one or the other, it can't be both rules.  I think the second rule of within 75 feet of each other is just made up, but I wanted to check to see if anyone has a source for that rule.


texts: How is the cockpit rear view of an Airbus A340?

texts:
Before anything I know this can be sound something stupid and obvious, but I swear I lost 3 or 4 hours searching images and videos before posting this question. So please be mercy with my poor knowledge.
I'm looking for a view of the rear side of the cockpit (when the door is, and the third and four ocuppant seat is).
I only get a very partial views, and the more detailed image is a diagram from the cockpit deck layout (the following is an example from A330, I could get the A340, but I'm not looking for a diagram):

Everyone knows the typical eye-lens shot of the panel, but it was impressive to me that get one of the rear view is really difficult, more even after the tragedy of the Germanian, where a lot of shots has no relevance with I'm looking for.
Any help will be preciated.
Thanks in advance.


texts: At what altitude after takeoff is thrust reduced for airliners?

texts:
When is thrust, after take off reduced for jumbos and smaller airliners?

Is it any different for jumbos and smaller airliner aircraft?


texts: For what reasons might a taxiway be mistaken for a runway?

texts:
In this article, an airliner landed on a taxiway instead of a runway. What might be the reasons that a pilot can mistake a taxiway for a runway?

(I mostly know the answer for this question, but I want to see what you guys can find out too as well as making a reference point for others.)


texts: Do other countries create the equivalent of a TFR when US VIP's visit?

texts:
In the US, there's a TFR everywhere a designated VIP (US president or vice president) is going to be. When (most?) foreign VIPs visit the US, I don't think there are TFRs in place for them (unless the location coincides with our VIPs).

Are there TFRs (or international equivalents) in other countries when the US VIPs are there?


texts: Throughout aviation history, what airships were metal clad?

texts: Throughout aviation history, what airships were built with metal skin instead of fabric or other material?


texts:
This video shows an aircraft touching down like a helicopter on some gravel, is this possible or is the video a fake? Are there any other videos out there?

Facebook video
Similar one on YouTube


texts: What is the difference between flutter and vortex induced vibration?

texts:
During flutter, the airfoil oscillates with a large amplitude, which generates vortices at the wake. In vortex induced vibration (VIV) the oscillations of the airfoil are caused by the shedding of vortices. Both flutter and VIV have airfoil oscillations and vortex shedding.
How are they different other than the cause and effect relation? And also how to distinguish which one is the cause and which one is the effect for a case where we don't know beforehand whether it is flutter or VIV?


texts: What are these markings under the passenger door?

texts: Is there anybody who can explain what the markings just below the passenger door edge do?


texts: How do you choose engine placement for under wings engines?

texts:
I'd like to know how you choose the location of the engines under the wings, in the case of a 4-engines aircraft with low wings (and therefore with engines under the wings).

Concerning the longitudinal location, what are the constraints? Nacelles are usually in front of the wing, but why? I know there is a security constraint, especially with high bypass ratio engines, but is that all?

Concerning the lateral position, you want to reduce the bending moment of the wings, and therefore have your engines close to the wing tips during flight. But one could also say you want the engines close to the CG to reduce bending moments on the ground... Which constraint is dominant? And why can't we have to engines close to each other? (far enough to avoid flow interactions)


texts: What are the V-Speeds used during a normal takeoff in a multi-engine airplane?

texts:
This is what I know:

$V_1$ is the takeoff airspeed after which the aircraft must take off, no matter what happens after $V_1$ has been reached. That's the easy part (I think).
$V_R$ is the rotation airspeed

Are there any other $V$-speeds?

What I'm specifically curious about:

Is $V_1$ related to runway length?
Is there an absolute maximum $V_1$ for each aircraft type? If so, can it vary based on conditions (takeoff weight, density altitude, etc.)
Are there circumstances where $V_1$ is higher than $V_R$? If so, does that mean that $V_1$ is never called on a normal takeoff? (this is the case for most light aircraft, but I guess the whole concept is not applicable in that case)
What exactly is $V_2$?
Is there a $V_3$? (and so on)

Anything else worth knowing about $V$-speeds?


texts: Retreating Blade Stall, P-Factor, and Gyroscopic Precession

texts: Most airplane pilots are aware of P-Factor in propeller driven aircraft and that it tends create a torque in phase with the lift imbalance over the blade disc, resulting in a yaw moment about the airplane's CG.  Curiously I'm surprised that it does not act to cause a pitch up moment as one would assume that to be the result of gyroscopic precession acting 90° out of phase with the application of the reaction forces.  This occurs that way with the retreating blade lift imbalance in helicopters leading up to a retreating blade stall if the airspeed is high enough through the rotor disc.  Retreating blade lift imbalance is a result of lower relative wind speeds passing over the retreating blade than the advancing blade.  But instead of resulting in a rolling moment towards the retreating side of the rotor disc, it results in a nose up pitching moment due to gyroscopic precession.  Which raises the question:  Why is gyroscopic precession present in a helicopter rotor due to lift asymmetry over the disc but absent in a propeller?  Gyroscopic precession causes phase shifts in resultant forces on propellers when the propeller disc is pitched or yawed in aerobatics or tailwheel aircraft operations, but P-Factor does not cause this as well?


texts:
I was trying flightgear simulator since I am not a pilot (but have completed ground school) and one thing I have noticed is that the P-Factor increases with thrust applied whether taking off or in cruise flight.

Is this realistic? Does P-Factor vary based on thrust?


texts: What is the minimum price for a full Glass cockpit for the size of 6 passengers aircraft?

texts:
I am working on my final project at school and currently looking for the information about avionics system. We design a concept amphibious aircraft with the info as listed below:

2 pilots in the cockpit
6 passengers
Aircraft Mission: Leisure/ Passenger Transport/ Cargo
Cruise speed: 130 knots
Range: 400 to 600 nm
Service Ceiling: 14,000 ft

The customer wants the aircraft to be certified by both FAA and TC with installed IFR system. From FAA I got all the requirement for IFR and decided to design a glass cockpit with a budget of 20,000 - 25,000 USD. However, when looking at the different company such as Honeywell, Bendix/King, Garmin, etc., the price is too high for a newly installed glass cockpit. Therefore, I just wonder if there is any cheap, certified (FAA), and safe products available and what are your opinions regarding the idea of glass cockpit design for the mentioned aircraft above. I saw several cheap products from DYNON and ASPEN, but not very sure if their products are certified by FAA.

I really appreciate any help or comments from you guys. thank you!


texts: What is this military turboprop aircraft?

texts: I took a video of this military turboprop aircraft on August 6, 2020 at 7:03 PM in Long Beach, California. Here is a screenshot of it:


texts: Does an X at the ends of a private runway mean it's inoperable or does it mean its restricted to the public?


texts: What are the operational limitations on ADS-B DO-260A (as compared to DO-260B)?

texts:
First off, here is my understanding: I'm primarily concerned with retrofit aircraft.

A number of Asian countries (and Australia) already require ADS-B to DO-260A standard.

The European mandate is set for June 7, 2020 (DO-260B).

The North American (FAA) mandate is set for January 1, 2020 (DO-260B).

Am I correct in my assumptions?

After the deadlines, what are the operational limitations (assuming the aircraft is equipment with DO-260A)? Is the aircraft banned from the airspace completely or is it still possible to operate but get undesirable routing (such as low altitude or positioning)?

What is involved in upgrading to DO-260B? What are the differences between the standards?


texts: Why is the pitching moment of this symmetric aerofoil non-zero?

texts:
As I understand it, the pitching moment coefficient of a symmetric aerofoil should be zero, under potential flow assumptions. Obviously, approaching stall and post-stall, these assumptions are invalid and the pitching moment coefficient would no longer be zero.

However, looking at this graph of pitching moment coefficient against angle of attack, for a NACA0009 aerofoil at Re = 1e+6, it seems like Cm does actually vary considerably at low and moderate angle of attack.

Why?


texts: Why does Vmca decrease with increasing altitude?

texts:
A question from a mock MEP class rating test:

Many thanks for your help.


texts: Did WW2 airplanes ever jettison their empty external fuel tanks to act as weapons?

texts:
Jettisoning an external fuel tank over a populated area is prohibited by the FAA as it will almost certainly cause injury and damage to the people in that area.
But did war airplanes during World War 2 ever use that fact to their advantage?
As an example, say a P-51 Mustang dropped its bombs onto a city/town as a part of its mission, and then they realize that their external fuel tanks are empty, and are ready to be jettisoned. Well, couldn't the P-51 just jettison the external fuel tanks over the city/town to cause some additional damage?
So, did war airplanes during World War 2 ever actually jettison their empty external fuel tanks over bombing targets to cause additional damage?


texts: Do different grades of leaded avgas differ in ways other than their lead content?

texts:
Although only one grade of leaded avgas (100LL, standing for 100-octane, Low-Lead)1 is in common use today, there were formerly a number of different leaded avgasses with higher octane ratings and tetraethyllead (TEL) contents (things like 100/130 and 115/145), catering to the large, high-compression piston engines of decades past; these higher-performance blends are now produced only in small-volume special-order batches for applications where even 100LL doesn’t cut it, such as air races.

Are there differences between the various grades of leaded avgas other than their lead content, or could one convert 100LL into (say) 115/145 simply by adding more TEL?

1: 100LL is only “low-lead” when you compare it to the even-leadier avgas blends of days mostly past; it still has a considerably-higher lead content than leaded mogas ever did.


texts: Why don’t aircraft have interlocks to prevent high-lift devices from being retracted when doing so would stall the airplane?

texts:
Most aircraft have high-lift devices on the wings (such as flaps, slats, droops, whatevs) to allow them to take off  and climb out at a reasonable speed instead of having to accelerate to near cruising speed while still on the runway; this enables the aircraft to use shorter runways, but also places it at risk of stalling if these devices are retracted too early in the climb (example).

Given the danger of retracting high-lift devices at too low a speed, why don’t aircraft have interlocks to prevent this from happening?


texts: When to go missed on a non-precision approach?

texts:
I am training to get my instrument rating and I have come across a confusing point.   I understand that, when flying a precision approach, you go missed upon reaching the decision height for that approach if visual reference to the runway environment is insufficient to complete the landing.   I also understand that on a non precision approach you will descend to the minimum decision altitude for that approach and then fly at that altitude until you reach the missed approach point, after which you will go missed.   My question is, how do you know when you've reached the missed approach point on a non-precision approach?

These three charts in particular confuse me:

In this approach, which has an option for either an ILS (precision) or LOC/DME (non-precision) approach, the beginning of the dotted line which signifies the missed approach path does not have any DME value or intersection information.   There is an intersection after it at 7.5 DME.   Which of these two points would be the missed approach point for the LOC/DME approach?   How would you know when you reached the MAP if it is where the dotted line begins?

(Click to view)

In this approach the dotted line which signifies the missed approach path seems to begin at the runway threshold.   If this were the MAP, (with no localizer) would you have to start a timer after you cross KOLLI intersection to know you have gone 2.4nm and thus are over the runway threshold?   Is the MAP actually at the beginning of the runway as it seems?   Are there any ways of knowing you are at the MAP without a stopwatch?

(Click to view)

Finally, this IAP is similar to the first.   Unlike the first though, there is no DME intersection after or near the beginning of the dotted missed approach line.   Is the MAP for the localizer approach here just at the beginning of the runway as it seems to be in the second approach?   Again, would you have to use a stopwatch or are there any other ways?

(Click to view)


texts: During an instrument approach, what are the obstruction clearance given?

texts:
I was wondering wether each segments of the approach has different minimum obstruction clearance? (E.g. initial, intermediate and final) From both terrain and man made obstacles.

If possible i would like it to be from ICAO, hence PANS-OPS. But any TERPS answers i would happily accept.


texts: What is the fourth contact for on the Bose A20 headset's mic plug?

texts:
Bose mic plug
The Bose twin-plug cable for the A20 headset has a 4th contact.

In addition, the fourth section is rounded somewhat.

Standard GA mic plug
In comparison, the standard microphone plug only has three sections, and they're all smoothly cylindrical.

I can't quite figure out why Bose would have done it this way. Anyone have an answer?


texts: What area to use for the lift/drag forces

texts: I'm trying to model the orbit of a satellite around the earth at 500km above the surface. I have the nose cone radius and the surface area of the wings so should I be using the cone radius for the drag and the wing area for the lift or wing area for both of them?


texts: Can I pass the EASA ATPL exams by studying FAA materials?

texts: If I have the theoretical knowledge required for an FAA ATP, could I use that knowledge to pass the EASA ATPL exams?


texts: What is the difference between Fly-By and Short-Turn?

texts:
By all definitions that my team and I have found, fly-by and short-turn (with respect to military unmanned air vehicle waypoint based flight) mean the same thing.  Briefly, this allows the pilot to fly within a capture distance of the waypoint but is not required to fly directly over or through it.  In other words, the pilot can start turning before the waypoint is reached.

Current Definition:
A short turn will be performed at the turn location.  A short turn indicates that the vehicle may begin its turn prior to reaching the waypoint and fly-by it instead of through or over it.

Is there any nuanced difference between these two states so that I might further clarify this in my definition?


texts: Term to differentiate between a flight and a flight instance?

texts:
What's a term to differentiate between a flight schedule (QF 72) and a particular instance of that flight schedule (QF 72 departing on July 25)?

For example, I might ask "Which flight are you taking", and you might reply "QF 72". What I really meant was "Which scheduled instance of QF 72 are you taking?"

The flight schedule and a specific instance of that flight schedule are both referred to as a "flight". What are the terms that more precisely differentiate between these two concepts?


texts: What is meant by a "congested area of a city/town/settlement" in FAR 103?

texts:
FAR 103.15 states:

  No person may operate an ultralight vehicle over any congested area of a city, town, or settlement, or over any open air assembly of persons.

I'm wondering what is meant by "congested area".  It sounds like you can fly over a city, town or settlement so long as it's not congested but...how is that defined?


texts: What is the best airfoil for Edge 540 Style Aircraft?

texts:
I need help picking an airfoil. I'm an artist and have limited knowledge of such things.

It's for a game with an aircraft similar to an Edge 540 / Extra 300.
Unfortunately I have a limited selection of airfoils though and need some suggestions for both wing and tail airfoils. (Don't have the ClCdCm for the real Edge)

I do have access to many (not all) of the airfoils listed on this site though.
https://aerodynamics.lr.tudelft.nl/cgi-bin/afCDb

Any guidance would be appreciated!


texts: Which aircraft require that the vertical position of the centre of gravity is checked?

texts:
We normally check the aircraft CG along the longitudinal axis and the lateral axis (sometimes referred to as the transverse axis) to ensure it is within limits. Until recently I was unaware of any aircraft that required a check and control of the CG along the vertical axis. None of the aircraft (B727, B747, DC-8, DC-9, L1011) that I have been involved in weight & balance detail for have required a vertical CG check. Recently, however, I have found that some B767 freighters do.

My question is: Are there aircraft other than some 767s that require a vertical CG check?

Edit in response to a comment: My purpose in asking the question was to learn how others might have handled a vertical CG check. You can see the method I used by going to http://terryliittschwager.com/WB/B767/load.html and searching the page for 'vertical'.

Additional edit in response to additional comments: Some comments have expressed the opinion that there is little or nothing that can be done about the vertical CG. In practice, the vertical CG of cargo (and thus the airplane) is easily affected by specifying which ULDs (unit load devices—the so-called "igloos") will be used for loading. ULDs come in various standard heights. 96", 64", and 45" are oft used heights but there are others, and an array of custom heights. A usually safe assumption is that the mean vertical CG across ULDs is no higher than half their height. In the case of the 767, the published weight & balance documentation gives tables for average CG heights of 42" and 36".


texts: Does an aircraft landing on a carrier increase the carrier weight before it touches down?

texts: The same question goes for any runway, but I guess that for small aircraft carriers, one might actually be able to measure the exact point of weight increases (e.g. measure the submersion of the hull). For helicopters, it seems that this is the case, so I would presmue the same for fixed wing aircraft.


texts: What is the difference between an engine "shut down", "cut-off" and "cut down"?

texts:
Explain please for non-native speakers the difference between these engine (jet or piston) terms:

shut down
cut-off
cut down

I'm studying at a civil aviation university to become a pilot and a teacher told me "shut down" is used when you switch the engine off, "cut-off" is used when the engine electrical supply fails, and "cut down" is when you reduce throttle setting. But I'm not sure it's correct.


texts: Has a passenger or cabin crew member ever flown an airliner?

texts:
Is there any documented case, excluding hijacking, where a passenger or cabin crew member had to fly an airliner (hands on yoke/stick) – even if just briefly – due to an emergency (pilot incapacitation being the most likely one) in which he/she had to replace the pilot mid-flight ?

Aside from talk-down aircraft landings of small aircraft and stand-ins as Pilot Monitoring (which are both beyond the scope of this question), the only case I could find is:

Helios Airways Flight 522 where a flight attendant was spotted in the captain's seat shortly before the plane crashed

Do you know any other cases ?

I'm particularly interested in cases, in which the stand-in pilot was unqualified to fly this specific plane, but absent such cases all stand-ins as Pilot Flying in an airliner count.


texts: How can Schrenk approximation be used to model lift load on a rectangular wing?

texts:
How can I use Schrenk approximation to calculate load distribution on my rectangular wing?
A worked example will be appreciated.


texts: The Sukhoi Superjet 100 features flight control system with characteristics copied from Airbus. Side-sticks, same control laws. But does it actually use any of the hardware or software from Airbus (under license), or is it an independent development based on detailed descriptions of the behaviour?


texts: What is this component in an Airbus cockpit?

texts:
I have noticed that on a lot (all?) Airbus cockpits, there are these "things" (for lack of a better term) under the panel.

I have highlighted them in this picture of an A340 cockpit:

What are they?


texts: What angle of deflection / pitch on the rotor blades can the controls generate?

texts:
I was wondering, if a pilot uses full input on cyclic and collective, what pitch angle can be achieved for the rotor blades? Is there a mechanical stop to prevent extreme angles of attack? And how would that interact with the blade pitch needed for auto-rotation?

Thanks!


texts: Can a view limiting device be used in an aircraft requiring two pilots?

texts:
Can a pilot use a VLD for IFR currency if the aircraft requires two pilots? Can it be used while carrying passengers? If so, is this ever done?

I'm thinking of part 121 airline pilots under FAA.


texts: Is there any difference in landing minima between ICAO and FAA?

texts:
The FAA IFR Landing Minima Chart has both ceiling and visibility minima regardless of approach type (straight-in or circling). I believe it means that a pilot should meet the both ceiling and visibility minima although he conducts straight-in approach procedure.

But in my country (not USA, we follow ICAO regulations), landing minima for straight-in approach procedure consists of only 'visibility'.

So I guess there is difference on landing minima between ICAO and FAA. But I couldn't find that information.


texts:
Some aircraft (A380, Concorde,...) are equipped with a trim tank in the tail. Transferring fuel from or to this tank help controlling the CG. This feature can only be achieved if there is fuel to transfer. If tanks are nearly empty, and CG must be kept aft, this fuel could not be usable, except if there is another mechanism to compensate for the CG.

Is the fuel from trim tank always usable? Does it count when calculating minimum fuel requirement for a travel?


texts: What is the relationship between drag and sink rate?

texts:
I was just brushing up on basic aerodynamics and I have something I want to clarify about flying in the region of reverse command. I went up in my 172 the other day and noticed the following while practicing slow flight:

I'm on straight and level flight, and I enter slow flight (dirty) the way I usually do. I pull the power back and then I raise the nose to a level attitude slightly to bleed off some airspeed while maintaining the same altitude. When I entered the back side of the power curve, I pitched for an airspeed that was significantly above Vso, but below L/D max, which in this case happened to be 55-56 Knots. However, this time I didn't add any power and I just pitched for 55 knots to see what would happen. The airplane started descending (sinking), which is really what I expected it to do.

My limited understanding of why this happens is that total drag (mostly induced drag at high AOA) exceeds thrust available and the airplane develops a sink to try to regain equilibrium. Is this correct? Can someone with more knowledge explain why this happens? Maybe I'm overthinking it... I just know that high drag at low airspeeds typically results in a high sink rate. I just can't explain exactly why. Some people have said that weight exceeds lift, but I'm pretty sure this isn't the case as the airplane is not stalled.


texts:
While randomly browsing on Google Earth and Bing Maps I found an airstrip in Mali.
Normally you assume a small village/mining site in the vicinity of the airport but other than the ruins of a supposed old settlement nearby I could not find anything.
Does anyone know the name of the airfield or any info why it is there? On Google Maps there is an image attached with an airplane (Beech King Air maybe) but not convinced it was taken there.


texts: What's the point of writing on a cockpit window?

texts:
Why would a pilot write on the cockpit window like this?

From: source


texts: What and where are "flotation seat cushions"?

texts:
Inspired by the question Why did the US Airways Flight 1549 passengers stay on the wings?
I read parts of the respective accident report[PDF]. They mention the flight was a
non-EOW (extended overwater) flight but was luckily equipped as such anyways and thus had life vests and
"flotation seat cushions".

Section 2.10.3.3.1 "Equipage" of the report states

  Because the accident airplane was equipped for EOW operations,
  it carried life vests for both passengers and crewmembers.
  However, given that the accident flight route was not an EOW
  operation, the airplane could very well have been equipped
  with only slides and flotation seat cushions as the primary
  means for passenger flotation.

I've never heard of such a device, I only know the life vests below a
passenger's seat. Can the seat cushion (the part where you sit on, I assume)
be detached from the seat to serve as a "swimming aid"?

Maybe it's different in the US and Europe. I sometimes fly from Germany to the UK
and the FAs never mentioned any cushions. How comes?


texts: What happens if you do emergency landing on a US base in middle of the ocean?

texts:
A theoretical situation.

I fly from Honolulu International to the Bejing but my private jet gets fuel starvation and then I land on the Wake Island airstrip.

What happens next? Would the military give me fuel or they would give me shelter and tell me to stay? Did such things ever happen?


texts: Why are the spoilers used as the backup controls instead of ailerons on the Boeing 777?

texts: While reading this question, I ran across an interesting unanswered comment.  Why did Boeing choose to use some of the spoilers as mechanical backup controls rather than the ailerons?


texts:
For some reason I ended up binge watching E-2s and C-2s doing shots and traps on YT. One thing caught my eye; especially during the approach, the pilot’s left thumb is in constant motion pressing a control on the yolk.
One imagines the radio PTT, but there seems to be no relationship between the clicks and talking during the times where both are visible, and it’s not like they are push-n-holding, it’s click click click!
So then one starts thinking about trim, but what madman designs a plane that requires so many trim adjustments during landing, and then requires a separate push for each adjustment?
Anyone know what’s going on? Here’s an example:

UPDATE: here's another example:

Look around 0:55 and again at 1:25 - his thumb is positively dancing. I can see in this video it is a hat, so I guess it is trim.
Never having flown anything larger than a s-twotter, what is going on here? I'm used to adjusting trim maybe one or two times in the circuit, this is nuts.
P.s. why the heck is there a privacy screen on the door?


texts:
I've been researching about helicopter flight without a tail rotor and the closest I've found is intermeshing rotors or this: https://www.quora.com/Why-dont-helicopters-have-rotor-blades-at-the-bottom

Looking at this new method:

Seen in this frame, the rotors are single winged and I'm guessing they rotate at opposite phases. What is this called and where can I find more information about it?


texts: BLEED FAULT lamp illumination under various conditions

texts:
In lots of commercial and defence aircrafts, bleed fault is annunciated because of mainly the following reasons:

Overpressure/Overheat
shut-off valve disagreement (i.e. failed open, failed closed)
pressure regulator shut-off valve fails
Precooler fails
Computer failure

However, when there is an emergency condition e.g. engines are lost/off/unavailable (i.e. no generators) and also no APU possible, should there be any bleed fault? Given that the aircrafts are only running on batteries, should there be a bleed fault because your sensors and computers aren't powered up completely?

I know that you have things like built-in autotest stuff that goes on before the computers are powered, but surely when the aircraft is on batteries/emergency power, should there be any bleed faults?


texts:
It seems like skywriting would be pretty difficult to learn, since there doesn't seem to be any way to step back and see if you made a mistake. And yet people have been doing it since the early days of flying.

So here is my question: how does one go about learning to sky write, and are there any tools to make it easier (a ground mounted webcam with a panel mounted display was an idea that came to mind, have no idea how feasible that is)?


texts: Does the center of mass for an airplane have to be over the wings?

texts:
I am designing a model aircraft that will have 4 propellers in a square configuration (think like a quadcopter) so that it can take off and move around like a quadcopter, then transition into plane flight like a VTOL aircraft.

For operating in quadcopter mode, it would be ideal for the center of mass to be in the center of the airframe (behind the main wing) for motor efficiency and agility reasons. If the CG is over the wing the front two motors will have to work harder than the back two, and while the PID controls will stabilize for this, it will decrease throttle headroom.


texts: How did the Thrust Reverser Deploy in Lauda Air Flight 004 crash?

texts:
How did the electronically controlled thrust reverser in Lauda Air Flight 004 (which crashed) get deployed in mid air without the pilot command. Was there a fault in the electronic controller, a hardware or software fault?

In his book Air Disaster Volume 2, the aviation writer Macarthur Job wrote

  had that Boeing 767 been of an earlier version of the type, fitted with engines that were mechanically rather than electronically controlled, then that accident could not have happened.

How could that incident not have happened in a mechanically controlled engine?


texts:
On cars, we have 'shock absorber' suspension that decouples the passengers and loads from the road vibrations, bumps etc.

On planes do we have any form of suspension that decouples the passengers & loads from the turbulence, and vibrations induced by 'bumps' in the air?

I imagine even if it doesn't use a spring damper system, whatever attaches the cabin to the outer shell of the plane will have some finite stiffness. If so, has damping of this spring been considered to avoid oscillations?


texts: Why does landing gear extend backwards and retract forwards?

texts:
As you can see in the below image the front landing gear is retracting forwards, meaning that it extends forwards. What is the reason why they are made to drop backwards instead of forwards?

Image Source


texts: Where can I find Delta flight schedule information in a structured format?

texts: I downloaded Delta flight schedules from here but would like this information in a spreadsheet. Does something like that exist?


texts: Which countries allow pilots to fly over the age of 65 for International Part 135 Operations?

texts:
The FAA does not have an age limit for pilots flying under Part 135 regulations, however ICAO specifies an age limit of 65 (with other restrictions after the age of 60).

The NBAA has a nice Age 60 Briefing which discusses this, but at the end they say:

  Most of the States that have authorized their pilots to fly as
  pilot-in-command in commercial air transport operations after they
  reach the age specified in 2.1.10.1 also authorize pilots holding a
  license issued or validated by another States to fly in their own
  airspace under the same condition.

  However, ICAO does not collect information on States authorizing
  pilots to fly in their airspace after reaching the age of 60 and
  cannot provide information on the subject. Pilots seeking such
  information must contact individual Civil Aviation Authorities.

Is there any resource available which covers which countries allow pilots to fly over the age of 65?  For instance, I know that Europe does not allow it, but that some others do.  I am particularly curious the countries close to the US, such as Canada, Mexico, the Bahamas, and those in the Caribbean, Central and South America.


texts:
RAT are common in airliners today to provide  emergency electrical and hydraulic power. Yet, firsts airliners (prior to WWII) may not require the same amount of power than today's airliners (which are bigger and require electrical and hydraulic power to keep all electric-assist requirements, computers, hydraulic actuators,...).

The historic section of the wikipedia article speak about windmilling on the FW-189's engine as a precursor to RAT, but I fail to see anything related to first device whose only role is provide power.

My question is: What was the first aircraft equipped with a RAT? Was it military or civilian (it may not be a airliner)?

EDIT: given the comment by Peter Kämpf, I edited the question to include all aircrafts. Thus having an answer mentioning both airplanes and other aircrafts.


texts: What is the use of this sharp edge found on the leading edge of a DA 40NG wing?

texts: It is found on both wings and there is also another long one near the wing root too.


texts: What is this hole on the left wing of the Eurofighter Typhoon?

texts: I came across the picture below and saw the hole near the centerline on the left which appears to have some carbon next to it. What is its purpose and where does the carbon come from?


texts: What sort of control mechanisms (i.e., PID controllers) do modern FBW aircraft use?

texts:
It's a well-established fact that aircraft like the Boeing 777, and all Airbus passenger aircraft that were designed after the A300, feature a digital fly-by-wire control system. Considering the Boeing 777 as an example, the pilot flying applies force onto their yoke and one of the flight computers (I'm not aware of the architecture(s) of Boeing FBW systems) interprets the input and changes the control surfaces of the plane accordingly.

I am wondering what control paradigms are used by Boeing and Airbus to translate pilot settings (i.e. trim), accelerometer and gyroscope data from the IMU, and feedback from the aircraft's control surfaces to re-adjust said control surfaces.

Would a simple PID controller suffice? If so, how would a single PID system be able to manage feedback data from different sources (i.e. how could a PID system handle feedback from a gyroscope and Airbus side stick at the same time)?

I understand that the accuracy of PID systems are fully dependent on the feedback they receive, so I would assume that software methods of error correction like Kalman filter would be employed. However, how can computer hardware from the 80s (such as the Intel i386) be able to sample data quickly and compute Kalman filter within acceptable response times?

I appreciate all answers, and I apologize if my questions require analyzing proprietary technical documents.


texts: How are the hours that count toward fatigue limits calculated by the FAA?

texts: Which part of the flight actually counts toward the flight hours limited by the FAA? Is there any accounting for the time spent in flight preparation in so far as compensation or hour limits?


texts: What causes a slight increases in indicated stall speed with altitude?

texts: Theorectically, the stall speed in IAS doesn't change with altitude, but this graph above shows the stall speed actually starts to increase a little from above a certain altitude. How can this be explained? Is it something to do with a compressibility effect?


texts: Is it possible to revive a pilot who has had a medical condition in a seated position in a small aircraft?

texts:
I recently learned of a business executive who sold his company jet (single pilot operation) after his corporate pilot (in his 50ies) fell to the ground during the pre-flight inspection of the aircraft and died. He and his family were about to go on a trip. Very lucky guy. Obviously, he could have just paid for a qualified 2nd pilot to always fly in the right seat, but thats not the point of this question.

It got me to thinking. Is it possible to revive a pilot who has stopped breathing and/or who's heart has stopped beating in a small aircraft in a seated position? Assuming of course aircraft is in cruise with plenty of altitude.


texts: The cost of these aircrafts in modern US dollar?

texts: Could you tell me where I can find the development cost and market price of a Fairey Rotodyne, Convair CV-240, Martin 4-0-4, Ka-22 in current US dollar?


texts: During an IPC, is there any alternative to doing a precision approach?

texts:
My friend's plane is IFR certified, but does not have either an ILS receiver or a GPS receiver, either one of which is required to fly a precision approach.  As he can't fly a precision approach in his plane, and such an approach is required to be flown during an instrument proficiency check (IPC), does that require him to find another plane in which to take the test?

Alternatively, can he take the test in his plane with a limitation being placed on the signoff to the effect that he is not qualified to fly precision approaches? Or does it not matter that a precision approach cannot be flown?


texts: Are the guns on a fighter jet fixed or can they be aimed?

texts:
Are the (built-in) guns on fighter jets fixed, or can they be elevated up and down or panned right and left for aiming?

In other words are fighter jet guns aimed by pointing the whole aircraft at the target or can they be aimed independently?


texts:
In the air, concept of right of way does exist.

Does it also exist for ground operation as well? Possible conflict might come from where taxi ways intersect each other. Do pilots have to agree with each other who goes first or ground controllers do this for them?


texts:
Does the use or meaning of "chart" or "map" vary worldwide?

Is there a difference between a chart and map?


texts: What is the definition of climb gradient?

texts: I have a hard time understanding this topic. I understand it’s the percentage of rising over horizontal distance. Is that correct?


texts: What is the mathematical relation between CLmax and Reynolds number?

texts: I know that Reynolds number influences CLmax, but I am not able to find any formula with which I could plot a graph!


texts: What is an Air-Filed Flight Plan? Are aircraft capable of filing flight plan when in flight?

texts: ICAO Doc 4444 mentions to input AFIL in the departure field of flight plan if it has been filed in the air. What is an Air-Filed flight plan? Can aircraft crew file a flight plan in-flight? If yes what are the equipment that support filing flight plans when in flight?


texts: Difference between Assessment and Critique?

texts:
I was reading Aviation Instructor Handbook. I don't know the difference between assessment and critique. That would be great if someone could explain about it! Thank you!
In my understanding, assessment is just comparing student's performance to established standards without saying it was good or bad. And, critique is more like telling the way or process student performs was good or poor without comparing to the standards. But, I'm not completely sure.


texts:
To give a bit of background before I get into my scenario, I recieved my PPL in Canada two years ago, and then my night rating about 10 months after that. I was able to remain current but due to financial reasons I only just recently was able to go for my CPL.

The instructor I have now was just randomly assigned to me, and took me up to show that I was able to do upper airwork. Needless to say my skills had eroded, which wasn't all that surprising - so it took a few lessons to get all that rust off. Then we decided to practice diversions, which again my skills were eroded.

Now I have been studying all these maneuvers at home and playing them over in my head to get all the steps down pat, which I know isn't the same as flying. Having said that, I am not flying that regularly either which is down to my schedule and things pop up sometimes on my 4 days off so I do take full responsibility for that no doubt.

My instructor isn't all that encouraging though, he basically is trying to tell me without saying it, "stop wasting your money and stop flying". He doesn't try to really help, he basically criticizes me, which I am able to take, and he's not wrong on what he is saying -  but that's it, he doesn't really go much further than that.

He also has mentioned that my walkarounds are taking too long and that I am not fast enough at it, and I should be quicker with checklists, when all I am doing is being methodical and sure that I am not leaving anything out. Another thing is, half the time we don't do a briefing/debrief so the first time we practiced diversions again, we went up without a CPL diversion briefing and then we came back and he basically told me that wasn't up to CPL standard and this is how we do it.

So shouldn't he have done a debrief so I could know that? Another thing is he was late for a lesson by a half hour, but gave me flack for being 5 min late... I do feel frustration with him but I am not one to talk openly about that frustration so maybe I should grow a pair and talk to him about it? Before switching instructors?

Sorry for this being long but thanks to anyone who has tips or criticism.


texts: Is there a way to see the radar info ATC has?

texts:
I want to track GA helicopter traffic coming and going from NYC. I know that most routes the helicopters fly require them to pick up a transponder code from ATC, which means they are in the system.

Is there a public feed of that ATC data?

EDIT:

Just to clarify, As far as I understand, sites like flightradar24.com and flightaware.com only track aircraft transmitting ADS-B out or with Mode-S transponders. I'm interested in tracking aircraft with Mode-C transponders that have picked up a unique transponder code in order to enter the class B.


texts: Is there any way to tell the difference between MD-80 models?

texts: When I was at the airport a month ago I spotted a McDonnell MD-80 and took a picture of it and was very interested in this historic aircraft. I looked up the specs and this is what turned up. The MD-81,82,83, and 88 models all have the same fuselage length(147ft 8in) except for the 87 model(130ft 4in). They all have the same wingspan at 107ft 8in and the 81,82,83,88 carry 172 on a one class cabin except for the 87 which carries 139 on a one class cabin. So is there any way to tell the difference between the 81,82,83, and 88 models? The picture I took of the MD-80?


texts: Does anyone know more about the 1958 Heinkel-211 project?

texts:
Industria Aeronáutica Argentina worked in the 50s in a Jet airliner, Kurt Tank design, the IA-36, 'Cóndor', with simmilarities to 1958 Heinkel-211 project, turbines intake aspirating fuselage boundary layer as some Messerschmitt wartime fighter projects, eg, Me P-1110.
Impossible finding web info about Heinkel airplane, image is from 'Flaps' an Spanish magazine for young aviation enthousiasts. More info?
Blessings +


texts: What is the the origin of 12,500 pounds in the FAA's definition of large aircraft?

texts:
According to the FAA's definitions in 14 CFR 1.1, a Large aircraft is an "aircraft of more than 12,500 pounds, maximum certificated takeoff weight." I have heard this threshold was set based on the DC-3, but that makes no sense to me. Also, there doesn't seem to be any common-sense/international connection to kilograms (i.e. 12,500 pounds is roughly 5670 kg, not a nicely rounded-off 5700 kg).

What is the origin of 12,500 pounds being the cutoff between Large and Small aircraft?


texts: What is RTOW and how is it different from MTOW?

texts: Please explain what is RTOW, and what is the difference between RTOW and MTOW. Is there a link between the RTOW and the Weight and Balance Manual?


texts: Why are oxygen requirements based on pressure altitude?

texts:
The FAA's oxygen rules in §91.211 are based on pressure altitude. Assuming our lungs are like our engines and wings and dependent on density altitude, why are the oxygen requirements not based on density altitude?

If the answer is practicality, then would it not be wise to be more conservative with these requirements on hot days and more lenient on cold days?

Living in Colorado, the oxygen requirements are almost exactly what is usually required to transit the front range of the Rockies without an oxygen bottle, which leads me to believe practicality played a part. If density altitude were used instead, on a hot day you'd be unlikely to remain within the regulations and still transit the area without hitting anything made of rocks.


texts:
How can I switch off the yaw damper in an Airbus A350?
In the A320, this can be done by switching off the FAC, but the A350 doesn't have a FAC switch; it has prim and sec instead of FAC and ELAC.


texts: Does ATC use mode S addresses to identify planes?

texts:
By design, Mode S surveillance radar equipment uses global 24-bit airframe addresses to keep track of the aircraft it is tracking.

Are these addresses also used by higher levels of the ATC system, such as to fill in call signs, flight plans and so forth automatically when the plane first appears in a controller's domain? Or does that still depend on ATC assigning 12-bit squawk codes that pilots set manually?

Does the Mode S address appear in a flight plan when filed?


texts: Is the entire length of a B747 or A380 wing used as a fuel tank?

texts:
It is generally understood that the fuel tanks of aircraft are in the wings, but specifically, is the entire length of the the wing of:

an Airbus A380 Jumbo used as fuel tank?
a Boeing 747-800 Jumbo used as fuel tank?

What percentage of the wing length is used as a fuel tank and for what reasons, for:

an Airbus A380 Jumbo
a Boeing 747-800 Jumbo


texts:
Let's say some ships from the US Navy are in the middle of the Pacific Ocean.

Is there anything to stop another country, say the Chinese or the Russians flying around them in circles, either to watch what they're doing or just to piss them off and provoke a reaction?

I mean technically it would be international airspace?


texts: In which direction should a turn-back be made after an engine failure on a multi engined airplane after take off?

texts: In case one of the engines fails after taking off (let's suppose the left engine is the one that fails), which direction should we turn to go back to the airport? A left or a right traffic pattern?


texts: Where is the taxiway between the Boeing factory and Paine Field airport?

texts: How do the Boeing aircraft taxi to Paine Field (KPAE) from the Everett Factory? It looks like a 'road' connecting the airport and the factory. Do they use this?


texts: Why did this aircraft do a ‘spiral’ before landing?

texts:
There was this WizzAir flight two days ago, from BUD to PMI, and right before landing it did a ‘spiral’ like maneuver. I’ve attached a screenshot.

Why did it do that? It looks strange.


texts: Are planes allowed to fly in circles, and is there a minimum legal altitude for takeoff and landing?

texts: I live near a small, possibly private, airport. Every day there are small planes flying low over the neighborhood in circles for over half an hour.  They appear to just be flying for recreational purposes. They're also coming in and leaving low enough to be seen through the tree/wire lines and directly over houses.  I have seen the airport's grass runway, and it is quite large, so I don't see why the plane wouldn't be able to just land without circling so long.  Why would a pilot do this and is it legal?  Also, this is not a rural area, it is a highly-populated city.


texts: Why does the Yak-28 cockpit have two attitude indicators?

texts: Why are there two attitude indicators in the cockpit of the Yak-28? Below is a picture from this YouTube video.


texts: What is that A340 cockpit panel on the glareshield?

texts: I want to know the panel's name and how it works. This picture is an Iberia Airbus A340-600


texts: How much lag does an Attitude Indicator experience?

texts:
How much lag does an Attitude Indicator exhibit when it is working as designed? Other than well-known problems like tumbling beyond certain limits in pitch and roll, and precession errors from the erecting system, does a gyroscopic AI experience lag that makes it unusable for turbulent or gusty conditions?

Similarly, are there any conditions that would cause an AHRS-based AI to exhibit lag or otherwise show an incorrect indication of the horizon relative to the aircraft?

(Inspired by comments on this answer)


texts: Can windshield washer fluid be used to deice small airplanes?

texts:
This question is related to small single/twin engine general aviation airplanes with aluminium construction. I understand that it is generally not recommended to use windshield washer liquid to deice an airplane.Based on your personal experience can someone validate this eitherways? I am looking for answers like:

  Used it once and my wing fell off

or

  Been doing this for 15 years with no side effects whatsoever.

As far as I know there is nothing in the POH for the planes that I'm currently flying ( C152 and Piper Dakota ). Also there is a significant price difference in the price of common windshield washer fluid and stuff like TKS. Also the question is limited to deicing the metal parts like the wings and the stabilator, not the plexiglass.


texts: Does a pilot follow the PAPI lights in the same way in all categories of aircraft?

texts:
Since there are different dimensions of aircraft in various approach categories, I wonder what changes pilots in different aircraft have to make when following the PAPI lights. I know that 3° (for example) for one aircraft is the same for all other aircraft, but different categories might have different touchdown points when following the same glideslope due to the MEHT.

Since the PAPI is fixed, what differences are then when flying it in two different aircraft? Does the size of the aircraft change the flight path in any way? Will I always touch down at the same spot?


texts: Does the civil industry use the CAN FD bus?

texts: Does anyone know if commercial aircraft are using the CAN FD communication bus?


texts: How can the CVR from a Cessna 560XL only contain old records and none from the fatal accident?

texts:
Is it possible that the CVR from a Cessna 560XL is just showing old records and nothing from the fatal accident when the plane crashed?

I´m talking about the airplane crash in Brazil, where a election candidate was killed. The investigation team said that the data in the CVR contained only old data and they could not pinpoint from when those recordings were.


texts: Locked out of private jet - how do you get in?

texts:
Ok I'm not a jet owner, I'm a novel writer. I wanted to get my airplane facts right for the story.
Say my character has a mid-size (can go overseas) private jet. Has a door lock on the outside door and cargo bay. The bad guys stole his keys, so now he's locked out. My character is a pilot and is with a friend who is a jet mechanic. If the mechanic has tools, and 24 hrs, would they be able to get in to their jet and fly it?

If so, how would the mechanic go about getting in (while leaving the aircraft in flyable condition)?

Or would the characters need to call a locksmith?

I was thinking pretty high in the sky (I was going to have the mechanic literally unscrew the door and then put it back on) but then I thought I'm probably being unrealistic and I should ask someone who's actually worked with jets.


texts: What is the weight at which an aircraft no longer requires a licensed pilot on board in Europe?

texts:
According to this (somewhat dubious looking article):

  Since it is so light, the FlyNano falls under the weight of what is considered to be a plane, so in most countries you won't need a flying license to take this baby to the skies.


texts:
What are the pros and cons of high service ceilings for fighter jets?
Can they bypass radars and attack effectively at high ceilings?


texts: Why the excessive wait after shutdown before using the manual starter valve on the PW1000G?

texts: Why must there be a long period (measured in hours) between shutdown and startup, before using the manual engine start valve? Nine hours seems excessively long.


texts:
What is engine-out taxi out time?

a) The time between the first movement of the aircraft under its own power and the start of the last engine

b) The time between the first movement of the aircraft regardless if it's being pushed back without any engines running and the start of the last engine

And one additional question - how would you define the the start of the last engine?

a) The moment the fuel valve is opened

b) The first moment the engine is running (stable N1, fuel flow, oil pressure and temperature, etc.)

c) Something else


texts:
If one centers the gyro-copter in a thermal and then simulates a hover facing headwind; can the gyro-copter climb up like that ?
Is it technically possible or is it advisable....


texts: Deployment of leading or trailing edge flaps - increase or decrease the angle of attack and critical angle of attack?

texts:
There are a number of similar questions, but I'd like to clarify the increase or decreases between the angle of attack and critical angle of attack. According to this article, "When the pilot lowers the flaps, two things immediately happen: the wing camber and the AOA both increase."
With regards to leading and trailing edge flaps is it accurate to say deployment will increase AoA and the critical AoA?


texts: Is there an equivalent of the Threshold Crossing Height for departure procedures?

texts:
The definition for the Threshold Crossing Height is, according to the sources that I have checked, "the theoretical height above the runway threshold at which the aircraft's glideslope antenna would be if the aircraft maintains the trajectory established by the mean ILS glideslope or MLS glidepath" (source). FAA's Aeronautical Information Manual states:

  5-4-23 Threshold Crossing Height (TCH) has been traditionally used in “precision” approaches as the height of the glide slope above threshold. With publication of LNAV/VNAV minimums and RNAV descent angles, including graphically depicted descent profiles, TCH also applies to the height of the “descent angle,” or glidepath, at the threshold. Unless otherwise required for larger type aircraft which may be using the IAP, the typical TCH is 30 to 50 feet

Since every runway seems to have its individual pair of TCHs values (one for each Displaced Threshold), I was wondering if there is any similar "Threshold Crossing Height" value that indicates the optimal height above DER (Departure End of the Runway), for each of a runway's thresholds. Does in the case of a departure the "35 feet above DER" rule apply to every runway?


texts: Why are "canard" not used on commercial aircraft?

texts:
As of today and as far as I know, there is no commercial aircraft with canard, while they are used on several military aircrafts (like Rafale, Typhoon).

Plus, during take off the empennage pushing the rear of the aircraft down to pitch up add pressure on wheels, and this was for example one big design flaw on the Concorde:

  Because of the way Concorde's delta-wing generated lift, the undercarriage had to be unusually strong. [...] Combined with the high airspeed at rotation (199 knots indicated airspeed), this increased the stresses on the main undercarriage in a way that was initially unexpected during the development and required a major redesign..

I feel like addind a mobile canard in front of the plane would help to rise the nose up to take off.

Why are "canards" not used on commercial aircraft?

Edit about possible duplicate: I do not feel it is a duplicate of this question because "my" plane would be a three-surface aircraft with a canard, a main wing (not delta but classic) and conventional tail-plane. The canard would be mobile and add pitch control.


texts:
From what I understand (not much), you need good specific impulse to travel long distances with, say, flyboard.

I know that RP1 has good specific impulse. I wonder if he used it, and what type of oxidizer/propellant would be most efficient for this task, and feasible (very small engine, not that high temp) .

To be specific: The question is if the efficiency (in terms of travel distance per unit mass of fuel) could be improved by choosing another type of engine/fuel?


texts: Can I change the max bank angle on the Garmin G1000 in the C172SP?

texts: I wonder if I can change the max bank angle on the G1000/GFC700 avionics in a C172SP, like you can on the MCP of the 737NG?


texts:
Would a stationary WWII fighter fall on its nose with full throttle and brakes on?

It's a general question, but I am interested in the Republic P-47.


texts: What records should a CFI keep to prove they took due care in the quality of their instruction?

texts:
I know there has been some cases where a flight instructor is sued after a current or former student does something that gets themselves (the student) killed or causes damage.

I know that there have been cases where a flight instructor has been acquitted by proving that they took due care in their flight instruction, and the accident was not a result of poor instruction.

What specifically would a prudent flight instructor do to ensure they are keeping detailed enough records to prove that they are providing adequate instruction and that a resulting accident would not be due to poor instruction?

What are the records a CFI is legally required to keep, and what are the records they should keep in addition to that?

This question is in context of CFIs in the United States.


texts: Where did the SOE agents sit in the 161 squadron Short Stirlings?

texts:
I asked this question on history.se, where it was recommended I repost here.

During World War II Special Operation Executive (SOE) agents were dropped into occupied Europe by No. 161 squadron of the RAF. This squadron used the Short Stirling bomber up until March 1945.

In the Short Stirling, the pilots were separated from the flight engineer and wireless operator. There is also this picture on Wikipedia, which appears to show the interior of a modified Short Stirling that could carry passengers?

My question would be: In a typical 161 squadron mission, where in the Short Stirling would the agent(s) be located?


texts: How often is a commercial (airliner) flight flown without autopilot?

texts:
When it comes to commercial flights, I am aware that once the aircraft has reached a certain altitude, the autopilot activates and assists the pilots in flying the aircraft. It makes being a pilot on a long flight a less tedious job.

But what is the ratio of total flight hours to autopilot-flown hours during a typical flight?


texts:
What type of engine is mounted on the Cessna Citation Hemisphere?

Image Source

That does not look like a high bypass turbo jet engine.  If its not a high by pass turbo jet engine, and given a high bypass turbo jet engine is the most efficient engine, why was it not used for this particular aircraft and why was the particular engine chosen for this aircraft given its cruise speed is similar to that of aircraft that use the high bypass tubo jet engine?


texts: What is the normal descent rate for airliners?

texts:
A few days ago I was on a flight from SFO to AUS (Airbus 320) and I was shocked by the steep angle of descent into AUS. I have been on over a hundred commercial flights but I've never experienced such a steep descent. I checked the flight on flightaware.com and noticed that the descent rate was 3,000 to 4,000 fpm. On other days the descent rate is closer to 2,500 fpm.

Flightaware data: My flight vs another flight.

Two questions about this:

What is considered a "normal" descent rate for the A320?
What could be the reason for the exceptionally steep descent compared to a normal flight?


texts: Where can I get a graph of lift coefficient against AOA for a symmetrical airfoil?

texts: Where can I get get a graph lift coefficient against AOA for a symmetrical airfoil ? I am asking for a source or link to a graph or table of AOA against Cl of any symmetrical airfoil.


texts: What's the relationship between aileron deflection and roll moment?

texts:
I'm wanting to build a laterals-only kinematic model in MATLAB considering only the ailerons for control inputs and was wondering if anyone has a rough guideline for the relationship between their deflection and the resulting roll moment.

EDIT: The answer from @PeterKämpf on the following question helped a lot (Thankyou Peter) but I couldn't understand the difference between p, dimensionless roll rate and wx, rolling speed in rad/sec. How can a roll rate be dimensionless?

His answer is here: How I determine numerically the roll rate of an aircraft?

Sorry, I couldn't comment on the actual post, I don't have enough reputation.


texts: Is it possible to obtain the lift and drag coefficients of a 3D body in ANSYS Fluent?

texts: Is it possible to obtain the lift and drag coefficients of a three dimensional body in ANSYS Fluent? Or, would it be acceptable to take the coefficients of several cross-sections along the wings and body and perform a weighted average calculation to find the lift and drag values for the entire craft?


texts: Why do some Canadian Class E airspaces have no ATC frequency on VFR maps?

texts: PPL student here, studying airspace. Looking at the airspace around Vancouver, BC (see Vancouver VTA) I see that most of the lower mainland is class E controlled airspace. "No Contact" tells me that there is no ATC unit to ask for permission. Why is it class E then in the first place? Why isn't it class G?


texts: Why does the B-2 Spirit have a pattern of thin white lines?

texts: Northrop Grumman's B-2 Spirit bomber is mostly black or dark grey, but has a symmetric pattern of distinctive, thin white lines painted on its wings and fuselage. I have not been able to find anything similar on other airplanes, so why does the B-2 have these lines and what is their purpose?


texts: What are the differences between third-party base maintenance, line maintenance and component maintainance?

texts: These are related to MROs(Maintenance, repair and operations) activities ?


texts:
I am looking for an Aerospace Engineering program in the EU. I heard the Aerospace Engineering Department in Delft University in the Netherlands is one of the best programmes.

I prefer English speaking countries, such as the Netherlands, Scotland, and Scandinavian countries.

To be more specific I would like to study about the operation of airlines, airports, maintenance, how to do aircraft take-off performance calculations, and regulations relating to the operation of EFB applications.


texts: As a general rule, must the cg of a tandem ultralight be greater than 25% mean aerodynamic chord?

texts:
As a general rule, must the cg of a tandem ultralight ( Re 500k-1,000k) be greater than 25% mean aerodynamic chord?

I understand the centre of pressure of a classic wing is at it's quarter point. It also produces a nose down moment, so that the cg and/or and horizontal tail moment need to offset this, or the plane will dive.
To provide a nose up moment, the horizontal tail must produce a tail down force.

If you want a tandem airplane, you want the exact opposite.

So the to provide a nose up moment, I would imagine you want the cg always behind the Cp ( 25% MAC) of the wing, but in front of the plane neutral point, as you want to the tail to provide an offsetting tail up force,(nose down moment)

Is this correct?


texts: What's the point in escorting a threatened flight with two fighter jets?

texts:
Two days ago I read in the news:

  Two U.S. fighter jets escorted a Canada-to-Panama flight back to
  Toronto after a passenger  allegedly threatened the plane Friday
  morning. The nature of the threat or why the passenger was agitated
  were not specified. CBS News  reported that the passenger told a
  flight attendant, "I have a bomb and I will blow up Canada."

What's the point of escorting the flight while it has been threatened by a passenger? How do they help to eliminate the threat?


texts: Is a turboprop or a turbofan more eco-friendly?

texts: If we compare them, which one wins? Why? And, what about CO2 emissions?


texts: Are there cases of a thrust reverser used on a turbojet engine?

texts:
In the case of a turbojet (with no "cold" bypass flow), the airflow being directed forward by an hypothetical thrust reverser can be really hot.

Depending on the location of the engine, this flow may be dangerously redirected towards the empennage and the fuselage.

For instance, for a fighter this would be a hazard for sensors, equipment, payloads including missiles, likely many other elements, and pilots:

General Dynamics F-16C (source: Wikipedia)

Are there turbojet engines fitted with a thrust reverser? Which aircraft are they used for? How is this problem dealt with?


texts: Why do airlines outsource regional flying?

texts:
The three major American airlines (American, United, and Delta) all have regional brands. These brands are actually operated by other airlines (ie: SkyWest). Air Canada has a similar regional brand called Air Canada Express.

Obviously, these flights are important for getting passengers to the airline's hubs. It also seems obvious that this type of flying is quite profitable because there are a number of regional airlines that are flying for these carriers. Why don't the big airlines just fly these routes themselves? Why have they all chosen the path of outsourcing?


texts: Do pilots have procedures and safeguards against unintended altitude captures?

texts:
Most advanced autopilots with a guidance panel allow you to select an altitude and fly to it.  It will often switch over to an altitude hold mode if the airplane is close enough to the selected altitude and the flight conditions like current vertical speed are right.  My question is about how vigilant the pilot has to be to prevent this altitude capture from happening at the wrong moment.

The Garmin G1000 manual describes the behavior like this:

  As the aircraft nears the Selected Altitude, the flight
  director automatically transitions to Selected Altitude
  Capture Mode with Altitude Hold Mode armed (Figure
  6-7). This automatic transition is indicated by the green
  ‘ALTS’ annunciation flashing...

  At 50 ft from the Selected Altitude, the flight director
  automatically transitions from Selected Altitude Capture
  to Altitude Hold Mode and holds the Selected Altitude
  (shown as the Altitude Reference).

However, this preselected altitude stays on as the flight proceeds, including during most mode changes.  There are some mode changes where this old altitude could cause problems if it initiates an altitude capture, like a transition to a go-around mode or an approach mode.  (For an example, see "A Sea Level State Of Mind" in this newsletter). The autopilot would try to reach the old altitude once conditions are right (which may require turbulence or other conditions to make the AP think it's trying to fly to the preslected altitude).  The plane would be doing what the pilot previously had told it to do, not what he was directing the plane to do at the moment.

From a human factors perspective, having the autopilot follow the old altitude target in a problematic scenario would make the system easier to understand, but would require more mental work from the pilot to maintain mode awareness.  Under certain conditions this altitude capture could potentially create a safety issue if the autopilot doesn't otherwise mitigate the sudden motion in an unintended direction.

Having seen a case where the pilot asked "why is that happening"  then realized he had mis-managed his altitude selector, I'm wondering about how smart the autopilot is and what the procedures are for managing the altitude selector.  Does the pilot usually expect the autopilot or flight director to ignore or clear the preselected altitude when necessary, or does he have to carefully manage the altitude selected to avoid an unintended maneuver?

EDIT: I'm asking if there are any safety features for altitude capture (like not allowing altitude capture while in glideslope mode) or checklist/procedures related to altitude capture.  If you think there aren't any of those and that the pilot takes full responsibility for any unintended altitude captures, please answer why you think so.


texts:
Can somebody please explain how I go about this problem?

A Cessna 172S is flying at 9842.52 ft from the ground and the engines stop producing power.

If the aircraft is in a glide configuration and the best (quickest) rate of descent recommended is 3.4 m/s (800 ft/min) at a speed of 68 KIAS. What is the maximum range that can be reached?


texts: Will this diagnosis from my cardiologist prevent me from getting a Class 1 JAA medical?

texts:
In 3 days I will have my Class 1 JAA medical test for the first time. However I said let's do a heart checkup before I go there and when I did this suddenly my cardiologist wrote that I have:

  Anterior mitral leaflet is slightly redundant and shows mild systolic prolapse. Trivial mitral regurgitation present.

He did for me a TMT and my performance was 97% as I'm 23 years old my heart rate increased to 195 bpm.

He told me this will not affect your pilot studies and nothing to worry about because it is normal and if you want to check it again, check it after 4 years, however no need to check it again.

Now I'm worried, will they stop me if they found out about this or what will happen?


texts: Is it possible to land a commercial aircraft with an elevator trim stuck at a high degree?

texts: I know this is not practical (considering there is normally not much use to use up to 30 degrees of elevator trim), but if you were on a Boeing 777 or 737, or similar, and the elevator trim was set into said position, and stuck there, would it be possible to safely land said aircraft in that condition?


texts:
I was intrigued by the assertion that COVID-19 depressing commercial aviation has lead to lower quality weather forecasting

  The aircraft observations are a key piece in the jigsaw of national and global weather data that is fed into computer models through a process called data assimilation. Multiple studies have found that aircraft are among the most important data sources for reducing the error in forecast models.

After some poking around, I found out the system is called AMDAR

  The AMDAR system predominantly utilises existing aircraft onboard sensors, computers and communications systems to collect, process, format and transmit meteorological data to ground stations via satellite or radio links. Once on the ground, the data is relayed to National Meteorological and Hydrological Services (NMHS), where it is processed, quality controlled and transmitted on the WMO Global Telecommunications System (GTS).

Is this system required by aviation authorities anywhere? Or is there merely some incentive system to encourage participation?


texts: Why does the moment coefficient for angle of attack = 0° not have to be negative?

texts:
I know for static stability reasons, the derivative of the moment coefficient of an aircraft has to be negative.

What I do not understand, why the moment of coefficient (cm) at all is allowed to be positive? Because when it is positive the aircraft pitches up.

Is it because when cm>0 I use my tails for trimming ? But is this "static stability" when I actively use my tail ?

I struggle with:
alpha = 0 ° --> e.g. cm=0.3    : the tail is used for trimming so that it counteracts the positive moment of the wing

alpha = 2° -- > e.g. cm=0.4 : now the pilot could also use the tail for trimming the higher moment

Thank you for your hints


texts:
I’m trying to get my ME endorsement now, and I find I can’t land very well. My instructor told me to forget everything I know about the Cessna, and that this aircraft should be landed with power. He told me to do a really low approach (compared to the Cessna) and keep the power on until about 7-10 ft off the runway, gently round out, level off (about four fingers under the horizon) and start decreasing power, wait for the aircraft to sink, then pull the column to three fingers under the horizon, power to idle, and land.

But I’m really confused:

Where is my aim point? I always do it depending on my feeling, so sometimes it’s unstable. Maybe use the bottom of the compass to match the runway number?
What’s the rate to reduce the power? My instructor told me the best condition was you touch down at the same time your power had been idle. But I don’t know when the aircraft will touchdown, so I always reduce the power to idle before the aircraft starts sinking. Is that OK?
When I was doing it, I didn’t know why the control column was really hard to pull during flare, and I had trimmed the aircraft on final. Maybe use more trim on a short final?


texts: Should 3 takeoffs and landings to stay day current be solo?

texts:
Let's assume  that I fly every weekend with a friend which is not a pilot. Can I log that time as PIC and count the takeoffs and landings toward the currency requirement as stated below:

  Sec. 61.57: Except as provided in paragraph (e) of this section, no person may act
  as a pilot in command of an aircraft carrying passengers or of an
  aircraft certificated for more than one pilot flight crewmember unless
  that person has made at least three takeoffs and three landings within
  the preceding 90 days, and -- The person acted as the sole manipulator
  of the flight controls; and The required takeoffs and landings were
  performed in an aircraft of the same category, class, and type (if a
  type rating is required), and, if the aircraft to be flown is an
  airplane with a tailwheel, the takeoffs and landings must have been
  made to a full stop in an airplane with a tailwheel.

Does sole manipulator of the flight controls means solo and by yourself (alone) in the airplane such as Cessna-172 or does it mean you can have a non-pilot passengers?


texts: What is the relationship between STARs, IAPs, and feeder routes?

texts:
From what I understood, if I want to do some approach procedure, I need to get to the waypoints marked at the STAR chart, and then I go to the IAF marked at the IAP chart through the feeder route. After reaches to IAF, I can make the approach as published.
Is the relationship between STAR, IAP, and feeder route correct?


texts: Would it be a benefit to install winglets on a Hawker 400XP? If so how much would the performance be increased?


texts: HSI KG 525 PNI non slaved or only slaved?

texts:
I'm in Germany and currently on a project about the avionics of an older airplane (PA28). Here is a link to a former reddit question.

My Prof. and me want to update the Avionics now - he asked me to do a bit of research - it is quite a good exercise for me and i learn lot this practical way (i'll become an aircraft engineer)!. I do the prework for our maintenance company and they'll supervise my work/planning.

The main idea is to install new:

Garmin GNS430
Garmin GMA340
Insight G4 + Sensorics
Becker AR6203 22
KI - 525A or Garmin G5 DG/HSI
Insight G4 for experimental stuff (UAS courses with our piper)

This avionic stays, but will be reconnected

KN53 (with GS) – goes to KI 204
KI 204
KAP 100 (AP)

Will be removed:

GPS150
KI 203 - Insight G4 will come here instead
KN53 (w/o GS)
KY 196 (2x COM)

Right now i have the DG - KG107 in it, but my professor wants to update it to a HSI..

Now the question is if a KI-525A has a built-in gyro or is there only the possibility to connect it with the KG102 (which we dont have)?
I would like to have the new Garmin G5 DG/HSI but it seems that it doesn't have an EASA STC. Garmin is kinda quiet.  What do you think - should we install the G5 (DG/HSI) and hope for a STC or pick another HSI (maybe Century)

EDIT: Took 3 questions off the topic


texts:
I've read here on Aviation SE that the aerodynamics of winglets on an aircraft are easily described as "extending the airfoil".  Thus, as I understand it, a winglet is like stretching the airfoil a few feet and "bending" it upward.

Now, this answer mentions the various types of winglets used in contemporary aircraft, but I'm not sure the B737-800s I've seen (such as the one in the below image) with double winglets perfectly matches any of those categories1.

source

Thus, my question is:  How can one best describe the aerodynamics (and benefits) of the second, downward-pointing winglet in the context of airfoil extension?

1 I claim that the 737-MAX's "split scimitar" as mentioned in fooot's answer is different than the aftermarket double winglet seen in the United (Continental) B737-824 in the image.


texts: What are the restrictions on performing intentional spins?

texts: I know there is controversy over the safety and utility of performing spins for training, but what are the regulations limiting them for training (solo and dual) or 'just for fun'?


texts: Why the pitch rate q is zero while angle of attack is changing and vice versa?

texts:
In the book Dynamics of flight, the authors present how the pitch rate q and the angle of attack $\alpha _x$ may vary:

Source: Dynamics of flight: Stability and control,
Bernard Etkin, Lloyd Duff Reid, 1996.

Why is the pitch rate q null while the angle of attack changes, and vice versa?


texts: Would the Wright Flyer have flown better with thicker airfoils?

texts:
The Wright Flyer(s) flew with very little wing thickness,would they have flown higher, faster and longer if the wings had greater thickness?

Secondly, how do thickness and camber affect a  wing's performance?


texts: Why the Mig21 don't use the ailerons like control surfaces on delta wings at landings or take off?

texts: Mig21 is a delta wing , so why do not use the ailerons like any other delta's ? For lowering the approach and touch down speed. It is not possible that?


texts: Is every emergency landing of a commercial flight documented?

texts:
A friend told me she was on a Royal Jordanian commercial flight in 2006 that had an emergency and was forced to land in a field in Greece.

She said the final destination was supposed to be Italy, with no scheduled stop in Greece. Nobody was hurt, and passengers were transported by bus to the Athens airport, which was not far. Perhaps the pilots had been attempting to reach Athens for an emergency landing.

Neither her nor I know much about aviation, but she described the plane as a small commercial jet holding 50-70 or so passengers.

I would like to know whether this kind of incident would create some kind of publicly-accessible record that I could look up. A commercial flight landing in a field seems significant enough to be recorded. But maybe as long as there were no injuries it isn't?


texts: Is there any guidance for writing the aircraft maintenance work cards? I want to find out some articles or books talking about this topic as I just start new job on it. How to write a good aircraft maintenance work card?


texts: Why don't both black boxes hold the same data?

texts:
As I understand, there are two black boxes on-board an aircraft. One black box, the Cockpit Voice Recorder holds the cockpit conversations and the other, the Flight Data Recorder holds essential flight parameters.

But why are the two black boxes holding separate data?
Why don't both black boxes hold copies of both the FDR and the CVR data for extra redundancy in case the other box goes missing or is completely damaged by the crash?
Are there any technical reasons for why this isn't possible or hasn't been attempted yet?
Is there any benefit of having the CVR and FDR in separate boxes?


texts: What do the yellow lashes/wings on the B737 PFD indicate?

texts:
When I was looking at a YouTube clip of a B737 doing a landing, I couldn't help but notice something on the PFD:

What do these yellow lashes/wings indicate on the artificial horizon?

Image Source (Added green arrows for question clarity)

They were on for the entire approach and remained on even after touchdown.


texts: What kind of low pressure causes abnormal RPM variations?

texts:
I was wondering what kind of low pressure indication causes abnormal variations in the RPM of a Lockheed L188 Electra. I was told one of the engines was presenting low pressure readings at certain rotations. Would that be low engine oil pressure? I have read the Electra manual and only saw indication of low pressure for either hydraulics or engine oil. The call of low pressure was originally made by the FE, which makes me think it should be something that would show somewhere in the flight station.
Thanks

In this link the only relevant low pressure indications I found were of engine oil and of hydraulics.
https://publicapps.caa.co.uk/docs/33/SRG_ACP_L188_REV2_ALL.PDF           .
Presumably everything should be there, although I was subsequently told that it could also refer to manifold pressure.

Here, https://www.spruemaster.com/blog/wp-content/gallery/manual/Lockheed%20L-188%20Electra%20-%20%20Electra%20Flight%20Control%20S%20ystem%20Part%201.pdf              ,
on page 30, fig.24, there is a picture of the flight station . I had originally only seen the four lights indicating low engine oil pressure (top left corner, listed as part of the "Ess Ac Inst Bus"), but upon closer examination, I found other things related to pressure as well. Perhaps I was biased because the first documents I read only mentioned hydraulics and engine oil.

So I guess my question should be: what kind of low pressure  is the cause of (or is caused by - the Captain was not very clear) abnormal RPM readings.
Thanks a lot

Ps: I tried to upload the flight station image here, but didn't manage. It sad it was too big. My apologies.


texts: Where can I download flight data containing pitch, roll and yaw angles?

texts: I'm researching the amount of solar energy available to photovoltaic cells placed at various locations on an aircraft's body. To calculate the angle of incidence of the sunlight on different parts of the plane I need a complete set of attitude angles of the aircraft (pitch, roll and yaw or equivalents) during flight. Can anyone tell me where to get this data?


texts: Where can a PDF of the TPP legend and supplemental materials be found?

texts:
When you buy a book of government approach plates, or a Terminal Procedures Publication (TPP) it comes with a legend and other supplemental documents along with it. Now that a lot of pilots are using digital flight bags like ForeFlight it's easy to overlook this stuff.

What I need is a PDF of these materials, but after a lot of searching I'm just not finding it. Does anyone know if the FAA publishes this digitally? This page mentions that it's available, but I don't see the download for it.


texts: How do fuel trim and air bubbles prevention work in inverted flight?

texts:
I was reading Why do many GA aircraft not have a "Both" fuel selector? and voretaq7's excellent answer got me to thinking.

He cites the regulations noting that the plane must only draw fuel from one tank or have a method for preventing air from entering the fuel lines. However all his examples assume gravity in a somewhat constant direction.

What do you do when this is not the case? For example in a barrel roll do you set the fuel selector for the wing going up first? Does it depend on the plane? Do planes in air shows have special fuel systems?

How does this regulation apply to aerobatic aircraft, and how is the regulation satisfied for such aircraft?


texts: Is there standard ticket data format specification for commercial flight operators?

texts:
I am new to this group and what brings me here is I am doing a research on ticketing solutions for commercial airlines. So I just wanted to find out if there's a international standard specification for data exchange between ticketing solutions and where can I find it (if it exists) ?

By specification I am referring to data fields and sizes that should be captured on a ticketing system like PNR, departure/destination, datetime & airport, ticket number & cost, no shows, etc


texts: Can you legally obtain Boeing maintenance documents?

texts:
With the correct keywords on Google, it is possible to find Boeing MPDs (Maintenance Planning Documents), as well as Task Cards, and other technical documents.

I'm wondering, could a software vendor with the need to access these documents legally obtain them?


texts: Could the reversers of a PW4000 on a 777 be deployed in-flight?

texts: Could the thrust reversers accidentally be deployed during a flight? Here, I’m referring to the PW4000 series on a B777, where the engine is similar to the type involved in the crash of Lauda Air Flight 004.


texts: What is the loading diagram for a C-130J?

texts:
I'm a student participating in a design project wherein we have to develop a paper design for a payload to be airdropped from a C-130J.  Naturally, I'd like to look at the weight and balance of the C-130 to see what sort of limitations we have (since we'd like to literally fill the cargo bay with multiples of this payload), but it does not seem to be available anywhere.  I found a CNI-MU emulator on Google Play that gives some basic information (basic weight/arm, crew weight/arm, fuel weight/arm), and I have a loadmaster form from the 2015 Defense Transport Regulations that shows me the cargo hold layout. However, something's not lining up.

The default information loaded into the emulator places the basic weight at STA 730 and the fuel at STA 750, which is roughly where the aircraft ramp begins according to the DTR cabin layout (which labels it as corresponding to the B/E/H models, but, according to the DTR, it applies to the J model as well), but it seems strange because, according to the CNI-MU emulator, that's around the quarter-chord of the wing, which is a little behind the center of the cargo hold.

In other words, I'm a bit confused and am looking for anyone who might be able to either make sense of the above or answer the following question:

What is the loading diagram for a C-130J (i.e., what is the basic weight/arm, crew arm, fuel arm, and payload stations within the cargo cabin)?


texts: Why do flaperons 'move down then up' on takeoff roll on a 787?

texts:
The flaperons on the 787 go through certain motions once the TO/GA is pressed. I've always seen it when the 787 is viewed from behind on takeoff. The motions are completely symmetrical, i.e., not related to pilot inputs.

Video example 1
Video example 2

I'm wondering why they're programmed to do that. The primary flight computers (PFC's) go through a complete self-check after every flight. Testing the ranges of motion is done by the crew after engine start-up. Seems like the wrong time to run a test.

The drooped outer ailerons do not go through a similar 'check'. My thoughts: calibration for their position, or drag reduction during initial roll. The latter would not explain the full down deployment though.

The frames below are from an on board video for a clearer image:

1) Taxi
2) TO/GA
3) Slowly full up
4) Back to normal.


texts: How does one calculate the taper ratio of a compound wing?

texts:
For tapered wings, Taper Ratio = tip chord/root chord.
Is this formula still valid for compound wings or do I take the taper ratio for each section and take an average?

Source: https://www.grc.nasa.gov/www/k-12/airplane/Images/area.gif


texts: For the CFM56 engine model CFM56-5B3/P, what does "5B3/P" mean?


texts: At what range does the turbofan start to become more economical than a turboprop?

texts:
By more economical I only mean 'burns less fuel'. I'm under the impression that at optimal cruise speed and altitude a turbofan will burn less fuel per mile per passenger than a turboprop, but I might be wrong. I'm also under the impression that this doesn't mean turbofans burn less fuel for every mission, that over shorter distances the time taken to reach the optimal cruise doesn't allow for the efficiency of turbofans to come into effect.
Also, unrelated to the efficiency of the aircraft, does the speed of jet aircraft play a significant role in the revenue of airlines? Does the speed increase of turbofans over turboprops mean more flights, or is this time saving not of great significance when designing and selecting aircraft?


texts: Why do lower molar mass rocket exhaust products give higher specific impulse?

texts: I tried to work this out.  My thinking is as follows.  If the same amount of energy is given to a low mass particle and a high mass particle, the low mass particle is faster.  A particle with a mass of 1 will be twice as fast as a particle with a mass of 4 but the momentum of the particle with a mass of 1 will be twice that of the particle with mass 2, which seems to go against what is seen with regards to molar mass and specific impulse.


texts: What are maximum G forces humans can survive?

texts:
I read that very high g forces could kill a pilot, brain pushing into the skull.

Is there a way of decreasing or surviving these forces and how would it work if you ignore aircraft capabilities.

If not what is the maximum survivable g force with current technology.