texts: Where can you find symbols (like these) that aren't on the legend?

texts:
I see a lot of these fan like symbols:

...on the Nav Canada Alaska Highway - Fort Nelson to Northway, 1:500,000 VFR Navigation Chart, but they're not anywhere on the map legend.

I presume they're marshland as they look a little similar to symbols I've seen on hiking maps, but I don't like assuming when making flight plans!..

Is there some universal reference somewhere that I don't know about? Are they indicating marshland, or are they something else entirely?


texts: Why is the nose landing gear of a Rutan Vari Eze up during parking?

texts:
I recently saw a Rutan Vari Eze parked at the airport and I was wondering why the nose landing was up during parking. How does it work for a pilot to get in? Can the pilot put down the landing gear while sitting in the cockpit or has the pilot to put it down while standing outside? And what's the idea behind such a construction, why isn't there just a normal landing gear?

Rutan Vari Eze during parking, with the nose gear up

Rutan Vari Eze before takeoff, with the nose gear down


texts: Is there any equation to bind velocity, thrust and power?

texts:
I am designing a remote controlled airship. I will tune it so that the lift given by Archimedes' Principle will exactly balance the weight of all the structure. It will be propelled by brushless motors with propellers on them.

As far as I have understood, for some given velocity $v$ the drag force $D$ will be given by the air pressure, some shape dependent drag coefficient $C_D$, the surface $S$ that the airship offers to the wind, and finally the squared velocity $v^2$.

Now, to keep some speed, obviously the thrust $T$ must equal the drag $D$. Now, I need to get to some equation for the power that I need to offer such thrust at such speed, given that I am using non-ideal engines, with non-ideal propellers etc. From a barely theoretical point of view, I know that if I want to apply some force to an object that moves at some speed, I will be using some power $P \sim Fv$. Now, since the thrust is generated in some way that actually looks very dispersive, I would like to know if there exists some relationship between the power $P$, the velocity $v$ and the thrust $T$, given some specific motor and some specific propeller. In particular, what are the parameters that one needs to know to get to this relation?

On example, I can imagine that some efficiency parameter for the engine, its RPM rate, its voltage, the diameter of the propeller, the pitch of the propeller, these are all going to be relevant to the equation I am looking for, but I wouldn't know how to explicitly figure out that.

It such a relation doesn't exist in an obvious or general way, could you just give me an idea of the efficiency of the propulsion? I mean, I know that $P \geq Tv$, but how much bigger is it in general? Do these quantities share the same order of magnitude, or the dispersion is very big compared to the actual propulsion?

As you can understand, I am not an expert at all on the subject, so I would appreciate anything that could get me started.

Thank you again!


texts: I know that it is kerosene based, but what exactly goes into it? Proportions of the various components would be helpful.


texts: Does the Boeing 737 NG have "5" radar altitude callout?

texts:
So, I was watching a video of a Boeing 737 NG land, and heard the "5" callout. Is that an airline option or something?

EDIT : link to video


texts:
If I understand correctly, gliders uses negative flaps while crossing between 2 thermals, but I don't understand why. For me:

positive flaps decrease sink rate but increase drag and thus worsen glide ratio
best L/G ratio is reached when flaps are in neutral position.
negative flaps decrease lift and thus require a greater angle of attack, maybe increasing drag.


texts: Is it normal practice to use 25 degrees of flaps when taking off at max weight in a PA-28-181?

texts:
I recently started renting a plane (PA-28-181) from a new flight school and had to get checked out before I had the "OK" to rent.

I had brought 2 family members with me during my checkout because...

They wanted to experience a small plane for the first time
My intentions with the plane were to have the option to fly with a full load of passengers (which I couldn't do in the planes I was used to flying) so I wanted to experience what flying at max gross weight was like.

During the checkout, while in the runup area going through my checklist, the instructor encouraged me to go back through my checklist. Eventually after hearing this suggestion multiple times and not understanding what he was hinting to, he came out and said "You need to set your flaps to 2 notches because we're at max weight".

I hadn't heard this before and I'm not seeing a ton of discussions about this type of thing online. His point was, the flaps would increase lift since we're heavy - that makes sense to me... But they also increase drag.

Note: this was not a short-field takeoff. 5,503ft paved runway, although it was hot (90+ degrees fahrenheit).

So, this leaves me with 3 questions:

Is this correct? When you're on the "heavy" end of the spectrum, should you be deploying flaps?
If so, what would be the proper flap setting at max gross weight?
Since, in this case, the point wasn't to clear an obstacle, would you simply climb out at Vy instead of Vx?


texts: Do nose cones work well at high angles of attack?

texts:
On a lot of fighter jets, I see a heavily slanted intake, such as the F-15.

I always thought this is to help ingest air at high angles of attack. However, what about something like the MiG-21?

There's no slanted intake there. Yet on Wikipedia it does say, "Its G-limits were increased from +7Gs in initial variants to +8.5Gs in the latest variants." And it has a citation for it.
So my question is, do nose cones work well at high angles of attack? And if so, how?


texts: Is it feasible to replace a C152's engine with multiple small turbine engines?

texts:
If I wanted to remove the piston engine from a cheap plane like a Cessna 152 and add small turbine engines with an equivalent thrust but weighing less, where would be the best place structurally to mount them? I'm thinking one small turbine on each side of the tail and two on the wings.

What problems may I expect?


texts: How is the cabin pressure maintained inside aircraft?

texts:
When aircraft is at high altitude, atmospheric pressure will be too low but inside aircraft pressure is maintained such that it is comfortable for crew and passengers. But how is it maintained?

As I understand that at higher altitude pressure difference can be too large which can deform the plane than how this is handled.


texts: What's field excitation in an electrical system?

texts:
"A field relay in the GCU (generator control unit) allows or prevents field excitation within the generator. When open, the field relay deprives the associated power relay of its ground, which causes the power relay to open."

It's an excerpt from the Citation M2's pilot training manual. What's field excitation here?


texts: Why are voice recordings stored and not transmitted?

texts:
With today's technology, why are voice recordings not transmitted, saved somewhere in case a disaster does happen?

Let's say a plane goes missing, they can spend a long time trying to salvage the black box, thus could take years to find out the real cause of the problem. Surely if the data was transmitted, stored somewhere, the investigators could then use this information to clearly determine the cause and highlight any technical failure to help prevent such things happening again.


texts:
In a previous question the P&W J 58 engine for the SR-71 was discussed. The engine was a new and innovative design combining the characteristics of a turbojet and a ramjet.

Before flying with such a new design I would think they would want to test it on the ground as much as possible to ensure the safety of the pilot and the aircraft. Otherwise you're sending a guy up with things that should work but so far only on paper. (I know that's what test pilots signed up for but they don't want to be reckless about it.)

J-58 ground test. from Wikimedia commons

From what I know a pure ramjet won't even operate at zero airspeed. What I'm wondering is how much can be learned from ground testing on such a radical new design, or any supersonic design for that matter? Can supersonic conditions be replicated on the ground?


texts:
I'm not sure if it's called nozzle or something else. I'm talking about the cone shaped part of GA engines at the rear.

Older engines, for example this Trent 700 had the cowling covering whole of the turbine -

Ow newer engines, the rear part of turbine is exposed -

What difference does this have on the engine performance? Is this to accommodate the increasing bypass ratio of modern engines?


texts: Can you mount a net between 2 helicopters for search and rescue?

texts: During situations where multiple people are in danger, I am wondering whether you can have a huge net mounted between 2 helicopters on a device with 2 arms on each helicopter, and when need to rescue, both devices would extend the arms to provide 4 points to connect a huge net, drop it down and then people in danger can just jump on it. Possible applications could be in firefighting or rescue offshore.


texts: How to calculate the flight envelope and maneuvering envelope for the B727-200F?

texts: I'm a student and my assignment is to make a flight envelope and maneuvering envelope of the Boeing 727F-223. But I don't find any of the values to calculate the flight envelope and maneuvering envelope. Can someone tell me how to find these values and how to get started with making the envelopes themselves?


texts: What are the regulations regarding crop dusting and flying low over private property. Do they have to file a flight plan and is there a way to make your private property a no fly zone?


texts: Why does an airliner have a shallow descent when heavier, opposite to gliders with ballast?

texts:
Gliders utilize water ballast to, among other things, descend faster:

But sometimes you need to get down fast: This is when water ballast is added.

In airliners however, the heavier the plane, the shallower the rate of descent.
Why is that difference? What is the physics involved?
Some 737 figures can be found here. And from the Airbus performance publication:

1.3.3. Weight Effect
Green dot speed (minimum gradient) is a function of weight. In the standard descent speed range (from green dot to VMO), the rate and gradient of descent magnitudes are reduced at higher weights. [emphasis added]

For the site readers based on some comments:
Descent – does not refer to landing or approach, rather the idle-power descent from cruise in clean (no flaps, speed brakes, or landing gear) configuration. The heavier an airliner, the longer it takes to get down.


texts:
From my understanding, a gyroplane (autogyro):

Is a rotocraft.
Uses an unpowered rotor for lift generation, instead of wings.
Uses a propeller for horizontal translation like an airplane.
Cannot take off vertically or hover contrary to an helicopter.
Can land vertically like an helicopter using rotor inertia.
Maybe simpler to build and maintain than an helicopter or an airplane.

(Source)

Are gyroplanes a technology that works but without particular application? Or do gyroplanes have well known uses for which they have significant advantages over airplanes and helicopters?


texts: Did the Wright brothers discover the three-axis control system for airplanes/gliders and the adverse yaw?

texts:
1) Various sites like this one: Orville and Wilbur Wright, The Inventors of the 3-axis Flight Control System, 9 Months before their powered flight at Kitty Hawk say that the two brothers invented the three-axis control system.

Is it true?

This is what they wrote in the beginning of their British patent: 1904-03-19 – 1904-05-12, Orville and Wilbur Wright, “GB Patent No. 6732, A.D. 1904 – Improvements in Aeronautical Machines”, Date of Application: 19th Mar., 1904, Accepted: 12th May, 1904, 5 pages, the first that was granted to them.

  "Our invention relates to improvements in that class of aeronautical
  machines in which the weight is sustained by the reactions resulting
  when thin surfaces, or wings, are moved horizontally almost edgewise
  through the air at a small angle of incidence, either by the
  application of mechanical power, or by the utilization of the force of
  gravity.

  The objects of our invention are, first, to provide a structure
  combining lightness, strength, convenience of construction, and the
  least possible edge resistance; second, to provide means for
  maintaining or restoring the equilibrium of the apparatus; and third,
  to provide efficient means of guiding the machine in both vertical and horizontal directions."

The expression "three-axis control" does not appear in the patent.

Regarding this patent, more precisely its German version, filed on March 23, 1904, (four days after the British text) the fact that the wing twisting and the vertical rudder had nothing to do with steering the machine was clearly explained by Harry Aubrey Toulmin (the Wright brothers’ patent lawyer) to Carl Pieper (his German correspondent) in a letter dated April 11, 1905. Here is the relevant excerpt of this document:

  “It is evident from the action of the German Patent Office that the
  invention is not yet understood by them. The entire purpose of the
  structure on which the application is based, excepting the front
  rudder, which is for another purpose, is to maintain the body of the
  structure level or parallel with the horizon. It has nothing
  whatever to do with steering, neither has it anything to do with the
  raising and lowering of the plane of flight. The setting of the two
  parallel edges of the supporting planes at different angles is solely
  for the purpose of maintaining the wide body of the machine parallel
  with the horizon. The rear rudder is solely for the purpose of
  overcoming the tendency to turn around a vertical axis which naturally
  results from setting the two edges of the planes at different
  angles. … We shall trust to you to place these matters before the
  German Office in the best way possible and hope that you will be
  successful in obtaining the allowance of the application.”

H. A. Toulmin, “Letter to the Carl Pieper”, Springfield, Ohio, April 11, 1905

The explanation above is puzzling and seems to nullify any kind of pretentious that the Wrights invented the three-axis control system as long as their patent application had “nothing whatever to do with steering”.

2) Regarding the adverse yaw, the description given in the patent and the explanation of Toulmin are quite clear. The Wrights proposed a method for counteracting this unwanted effect but where they the first who noticed it?

The Wright brothers glider as it appeared in the US patent granted on May 22, 1906, which is a bit more detailed than the drawing in the British patent, granted two years before.


texts: I've read that the SR-71 had no missile defenses because it could simply outrun any adversary. Is this still true? Or is it unlikely that the SR-71 could operate unimpeded in the face of modern technology?


texts: How did the US get the necessary knowledge to maintain their MiGs?

texts: I read a book entitled America's Secret MiG Squadron by Gaillard Peck some time ago. Just occurred to me though, how exactly did the US maintain these birds? Did we write any tech data? Did we acquire and translate it from elsewhere?


texts: DO-254 and microprocessors: how does it apply?

texts: How does DO-254 apply to commercial processors? For instance, I've noticed that "DO-254 certifiable" processors exist. Does that mean that these were designed with inherent redundancy?


texts: Has there ever been a tail-dragger with retractable tail-gear?

texts:
This comes from a slightly related question about drag from landing gear.

A tail-dragger is the old-school layout of aircraft, particularly WW2-era fighters. It's also known as Conventional Landing Gear.

The first two landing gear is usually retractable, but the tail wheel is not.

At least, I have never seen such a configuration with a retractable tail wheel. Has there ever been one?

Note: question excludes now more common tri-cycles.


texts: If an aircraft flies straight ahead, does it follow an orthodrome/great circle?

texts:
I understand that an orthodrome (line on a great circle) is the line with the shortest distance between two points on a sphere.

If an aircraft flies straight ahead, i.e. there is no wind, the rudder is not actuated and the aircraft is parallel w.r.t. the surface of the earth underneath it, will it follow an orthodrome/great circle?

I also understand that a loxodrome is the line that one follows when keeping a constant heading. This is the point where I'm confused, because wouldn't that mean that when flying straight ahead/along an orthodrome, the heading/bearing would constantly change? In other words, does this mean that one needs to turn in order to keep a constant heading?

EDIT: My question is not "which line does one follow when keeping a constant heading" (a loxodrome, I know that) but rather "what line does one follow when flying straight ahead (in the hypothetical case of no wind and no control inputs)?"


texts: Are civilian/GA pilots expected to "see and avoid" fast military jets in VMC?

texts:
I don't know if this also applies to the U.S. or just to Europe, but in Europe the civilian airspace is frequently used by military jets. On numerous occasions I've seen F-16's and other fighter jets using the same airspace I was flying in (both controlled and uncontrolled)

According to the regulations, we should "see and avoid" other traffic but does that rule apply when encountering these fast military jets? Let's face it: there's no way you can see and avoid a fighter jet approaching at +400kts.

Are there specific regulations covering this? Who's at fault when a midair collision occurs? (sadly it has happened in the past)

EDIT

It happened again last week: https://en.wikipedia.org/wiki/2015_Moncks_Corner_mid-air_collision

How can something like this happen? Don't F16's have their own radar?


texts: Why aren't plane engines mounted closer to each other or closer to the fuselage to reduce extra forces on the wings?


texts: Can a helicopter fly VFR at night in India?

texts:
As per the title, can a helicopter fly VFR at night in India?.
If yes, can the pilot ask for special VFR?


texts: What airplane model was this historic propeller attached to?

texts: I have a 9-foot historic wooden biplane propeller with brass edges. It does have a serial number, but it is tough to read. 2250 DN 152 6' 6" is what it appears to say. I am attaching a photo of it. Does anyone know what model it may have come from / how to find out which one?


texts: Why does pitot tube freeze at an altitude whose temperature is way below the freezing point?

texts:
It's supposed that Air France 447 crashed into the Atlantic because the pilots stalled the airplane when the frozen pitot tubes forced them to handfly it while cruising through the thunderstorm. But how could the pitot tubes freeze in that high altitude where the temperature was way below the freezing point? Isn't it that ice only forms on the aircraft between slightly above 0 and below -20 Celsius degree?

Edit)
Wikipedia: "Below −20 °C (−4 °F), icing is rare because clouds at these temperatures usually consist of ice particles rather than supercooled water droplets. Below −48 °C (−54.4 °F), supercooled water cannot exist, therefore icing is impossible."


texts: Does the B787 (Dreamliner) operate with higher cabin pressure?

texts:
The Boeing 787 Dreamliner's fuselage is almost completely made of composite carbon fibre material, which is not susceptible to metal fatigue.

The main reason why the cabin pressure in a pressurized aircraft is kept as low as possible is to reduce the expansion and shrinking of the fuselage due to changes in pressure differences, reducing metal fatigue in the long run.

Does the 787 use higher cabin pressures than other commercial aircraft? Boeing touted this as one of the revolutionary new features of the aircraft back in 2006, but does it actually use higher cabin pressure now that the plane is in use by airlines?


texts: What is the purpose of sum voltage monitor?

texts:
I was looking at the design diagram of actuators.
Every channel of the actuator is connected to a voltage differential transducer. The transducer outputs are fed to a sum voltage monitor. I could not understand its purpose.

How can summed voltage exist if there is a single sensor? Or am I missing something here?


texts: Would removing heat from the compressor and adding heat to the turbine increase a gas turbine's efficiency?

texts: Since a compressor compresses air, the air temperature increases due to P1/T1=P2/T2. When the temperature is increased it would be harder to compress - so would removing the heat from the air inside the compressor reduce the energy required by the compressor, and increase the efficiency of the engine? Also, since the turbine accepts hot air and uses the expansion of the gas to do work, would adding the heat extracted from the compressor to the turbine area increase efficiency even further?


texts: What are the radius of containment (Rc) and horizontal protection limit (HPL) and how are they related to Type Code?

texts: In ICAO Document 9871 (Technical Provisions for Mode S Services and Extended Squitter) page 30 they have mentioned it in the form of a table. But they haven't explained HPL and Rc in detail.


texts: What are the types of NOTAMs and how do USA NOTAMs differ from the ICAO definitions?

texts:
I'm looking for a complete list of the types of NOTAMs that can be found in the USA and under the ICAO definition. I looked at this question and it gives me a good starting point, but I'm not clear on how NOTAMs vary between the USA and when ICAO is used. Or maybe the USA is using "the ICAO way."

Is there a document that could help me compare where there is overlap and where there is a difference between how NOTAMs are defined in the USA and internationally. I assume there are ICAO definitions for NOTAMs that are used internationally.

If there are specific definitions for NOTAMs for countries other than the USA, that would fall outside the scope of my question here but might be an interesting additional subject matter for a very thorough answer.


texts: Why is the ICAO prefix for Alaskan airports "P"?

texts:
Mainland US airports all (to the best of my knowledge) have ICAO codes beginning with "K", however Alaskan airports all (from a couple of minutes rummaging about on FlightRadar24 and Flight Aware) seem to be prefixed with "P"?

Additional searching seems to indicate that Hawaiian airports are also prefixed with "P".


texts: Does a stopper (chock) really prevent the plane from moving?

texts: In Crime-Thriller movie American Made (2017), Barry put this stopper in front and in the back of the plane's front wheel. Do wheel chocks really prevent an airplane from moving?


texts: Are the panels in this vertical stabilizer part of the flight controls?

texts:
I've noticed some sort of "flight controls" on an A319 vertical stabilizer.

Here's the original photo

What are those things? Are they used for controlling the movement of the aircraft?
Source: Airliners.net (modified to indicate the segments of the vertical stab).


texts: What were the Concorde's emergency procedures for an uncommanded droop-nose extension in flight?

texts:
The Concorde had a droop nose, which swung down during taxi, takeoff, and (especially) landing, so that the pilots could see where they were going without the long nose getting in the way.  During cruise, the nose was raised to the horizontal faired position, and held there by a pair of mechanical latches; the nose (as well as a heat-resistant visor that slid in and out of the nose) were normally raised and lowered by means of hydraulics, but could also be dropped by means of gravity if need be.

While obviously essential for landing, takeoff, and (to a lesser degree) taxiing, I'd imagine that the nose drooping uncommanded during supersonic cruise (for instance, due to a failure of the nose uplocks, or a nose droop actuator hardover sufficient to break the latches and force the nose down) would have been a Bad Thing, due both to the nose-down pitching moment generated by the drooped nose1 and to the windscreen suddenly no longer being protected from the superheated air flowing over the aircraft (probably in addition to some other things that I haven't thought of).

1: I've no idea if this would be sufficient to cause a loss of control if it happened during supercruise, but it could hardly have been a good thing.


texts: What is the best pair selection algorithm?

texts:
Distance Measuring Equipment selection criteria is said “those closest to the aircraft and which intersect at an angle between 30 degrees and 150 degrees" (also said one whose geometry is closest to 90 degrees") (Not sure range or angle is more important in operation)

So question is what should be the best pair selection algorithm for coding in operation?


texts: This post shows the differences between winglets and raked wingtips. I'm curious why raked wingtips have been developed when there are tapered wingtips. What are the benefits of raked wingtips over tapered wingtips?


texts: Can I fly IFR in VMC if my instrument rating is not current?

texts:
If my IFR rating is not current, does this mean I can't fly by IFR, or does it just mean that I can't fly in IMC?

It seems that if it's just the latter, then it would make sense to fly IFR if the weather is still VMC. It would allow me to stay current on procedures while waiting for the opportunity to get my rating current.


texts: What are these grilles in the passenger cabin of this 787?

texts:
Below the windows, ahead of the seat, there are small grilles. Look:

Source: Airliners.net

What are those for?


texts: What kind of drone might be able to fly so high that it "operate(s) outside national boundaries"?

texts:
In the question What is a propellant burner trailer? I mention that

CNN and NPR have pointed out that the US president recently tweeted a surveillance photo of an explosion of a rocket on a launch pad.

The NPR article linked above speculates on the source of the tweeted surveillance photo, mentioning that it might not be a satellite product. At one point it says:

It was not entirely clear where the president's photo came from. Panda believes it was most likely taken by a classified U.S. satellite. But Melissa Hanham, deputy director of the Open Nuclear Network at the One Earth Foundation, believes that the resolution is so high, it may be beyond the physical limits at which satellites can operate. "The atmosphere is thick enough that after somewhere around 11 to 9 centimeters, things get wonky," she says.
That could mean it was taken by a drone or spy plane, though such a vehicle would be violating Iranian airspace. Hanham also says that the European company Airbus has been experimenting with drones that fly so high, they are technically outside the atmosphere and thus operating outside national boundaries. But she says she doesn't know whether the U.S. has such a system.

This comment suggests that answers to Is there a height limit to national airspace? address the height required to operate outside national boundaries, so I have modified my question to ask only the following.
Question: What kind of drone, Airbus or otherwise, might be able to do this?


texts: Aerodynamics and fuel consumption of a powered glider

texts:
I want to optimize the flight distance of a powered glider model airplane, without the use of soaring. I've studied some aerodynamics books, but still feel unsure about my conclusions. Please tell me if I'm wrong in the following:

1) The best fuel economy (liters per km) is for planes with the highest lift/drag ratio, typically so called gliders. The reason a 747 doesn't look like a glider to save fuel, is that it would be too difficult to build strong enough wings of that dimension.

2) Gliders are typically designed so that the best lift/drag ratio is when the airplane is in cruising mode with zero attack angle (horizontal). This is typically also when all control surfaces are neutral.

3) Optimum long distance cruising speed is at max lift/drag ratio, and when the lift is equal to the aircraft weight, given that the engine and propeller are also optimized for it. In other words, the speed where it sits stable in the air without any control. I can find this speed for my model glider by flying it at zero attack angle and with neutral control surfaces, and then increase the throttle gradually until the plane stops sinking.

4) Although the lift/drag ratio varies with speed, it varies very little around the speed that is optimum for long distance cruising. This is because lift-induced drag is a very small component of form drag (overall drag) at that speed. In other words, form drag is very close to proportional to the square of the speed.

5) If I want to increase the weight of the aircraft (for example add more batteries), all I have to do is fly proportionally faster to stay in the same zone of optimization for distance. Lets say the normal take-off weight of the glider is 1.4 kg. I quadruple the take-off weight to 5.6 kg. The lift equation says that my speed must now be doubled to make the airfoil provide four times the lift. This new speed will be very close to optimum cruise speed for distance, because of 4) above.

7) The speed has doubled, which means the drag has approximately quadrupled, so a new engine and propeller with four times the power and optimized for twice the speed must be installed.


texts: What regulations apply to a VFR flight from South Africa to Namibia?

texts:
I just would like to know what kind of flight plan, permissions, en route airway paths and other factors that need to be considered?

Other than the passport, PPL license and aircraft documentation and so forth.


texts: What could cause a noise like a hammer on an A320 in flight?

texts:
Edited question:

I was on an A320, asleep, around the mid-point of the flight at about 30,000ft. I suddenly heard a constant noise like someone hitting the plane from outside with a hammer. The noise wasn't too loud but it was distinct. I looked around, none of the passengers seemed perturbed.

The noise continued for 10-15 minutes, stopped, then started again after another 30 minutes. I was about to bring it to the attention of the crew, but the plane had started its descent by then.

Does anyone know what the noise could have been? And should I have alerted the crew?

Edit: Checked the linked questions. Its not a PTU, because the noises were heard mid-flight not during take-off or landing. Also, the second part of the question, can be answered.


texts: How do insects decrease aircraft performance?

texts: Is it true that insects hitting the fuselage could decrease aircraft performance and increase fuel consumption? Insects are small in mass. I think even a large amount of them accumulate on the aircraft's outer skin, it wouldn't be significantly enough to affect fuel consumption.


texts: How does a circulation control helicopter work

texts:
This essay describes that this helicopter uses circulation control of the rotor for cyclic and collective control, but not how circulation control works.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810017584.pdf


texts: Which country is responsible for prosecution if a crime is committed over international waters?

texts:
Theoretically speaking, let's say we're flying from Portugal to Cuba, on a Chinese-owned airliner. Whilst over the Atlantic, a crime is committed, and we land in the US.

Which country is responsible for prosecution? How is this determined?


texts: Is it common for automated control systems to use non-redundant sensors?

texts:
While reading an article about the Lion Air Crash with a Boing 737 Max 8, I was very surprised by the following paragraph:

  In designing the 737 Max, Boeing decided to feed M.C.A.S. with data
  from only one of the two angle of attack sensors at a time, depending
  on which of two, redundant flight control computers — one on the
  captain’s side, one on the first officer’s side — happened to be
  active on that flight.

My naive assumption was that any system that is capable of pointing an airplane towards the ground would certainly have redundant sensor input, and switch off if there is serious disagreement between the sensors.

Is it common to have non-redundant sensors for this kind of purpose in commercial airplanes?


texts: Why would a helicopter hold a 'nose-up' in hover?

texts:
(The Grand Tour; episode 2) SAS unit fast roping from a Blackhawk.

Why is the helicopter pitched-up? Actual scene footage have it like that for a few seconds while holding steady over a building. How come it's not flying backward?


texts: What is this fighter jet that flew over KJST?

texts:
This aircraft was doing low level flights over my office a few minutes ago.  From the route it was flying some of my coworkers thought it might have been doing approaches or touch and go landings at the local airport (Johnstown, PA (KJST)).

After it left the area I tried comparing it against pictures of active US fighters; but the wings didn't appear to match with anything I saw.


texts: Why do in-flight entertainment systems separate the left and right channels in their earphone jacks?

texts:
I have seen a number of in flight entertainment systems which utilise two 3.5mm jacks for their earphone jacks, instead of the 1 jack with 2 channels normally used in almost all applications.

An example (from Singapore Airlines) is shown below.

A normal 3.5mm 2-channel jack is shown below as contrast:

Why is this done only in airplanes (to the best of my knowledge)? Is there a reason behind this separation of audio channels?


texts: What's the plug used on airliners for ground power?

texts:
What's the plug pair called?
What's the ISO/whatever standard involved?
What do they look like close-up?
Is it pretty standard today worldwide?
Is the plug identical for the hugest airliners as for say commuters?
Is the power specs identical for the hugest airliners as for say commuters?
Is the plugpair used on any non-aviation (say, industrial) cases?
Do some craft have more than one type of plughole (ie, to allow for different airport standards?)
And military aircraft?
Do any small personal craft (I mean 2-4 seater craft) use the same plugpair, or in some cases do they just use a domestic-like plug (rather as a motorhome may have), or generally do small craft never have this?

 (found a pic but not a close up of the plug/hole!)

Is there a switch (for example, perhaps near the pylon in the first photo?), or a switch near the plug, or does it just hot connect?


texts: Why do airlines have geographical names in them?

texts: Why do airlines name themselves for example "Cathay Pacific" or "Virgin Atlantic". Aren't they indirectly limiting themselves to always fly over "Pacific" or "Atlantic"? It would be weird if Virgin Atlantic flies over Pacific and vice versa.


texts: How to balance a propeller aircraft for left turning tendencies?

texts:
(Source) Rudder twist on a Saab 91 Safir.

What are the design methods used to balance a propeller aircraft for left turning tendencies? I think it matters more the more powerful the engine(s) is.

A rudder twist seems to be one, not-so-detailed sources mention an offset engine, a slightly longer-, or differently balanced wing.


texts: In a part 91 formation flight within a mode C veil, are all the aircraft required to have their transponders on?

texts:
Two aircraft are planning on conducting a standard formation flight (aircraft remaining within 1 mile of each other) as follows in the U.S.:

Maintaining VFR below 10,000 MSL;
Remaining outside/clear of Class B/C/D airspace;
The route will be totally within the 30 mile mode-C veil of an airport listed in appendix D to Part 91, for example - Houston or Atlanta; (FAR 91.215)
FAR 91.111 will be complied with: see below:

§91.111   Operating near other aircraft.
(a) No person may operate an aircraft so close to another aircraft as to create a collision hazard.
(b) No person may operate an aircraft in formation flight except by arrangement with the pilot in command of each aircraft in the formation.
(c) No person may operate an aircraft, carrying passengers for hire, in formation flight.

No flight plan will be filed;
No communication with ATC will be established. (takeoff/landing will be at non-towered, uncontrolled airports in Class G airspace);
Both  aircraft will be equipped with a properly certified operable (4096 3/A, w/Mode C) transponder in accordance with FAR 91.215;

Question: Is it legal for only the agreed upon formation leader to have his/her transponder on with the other aircraft's
tansponder set to "standby?" Or do both airplanes have to have their transponders on?


texts: Why aren't the CVR and FDR required to store data for a longer period?

texts:
I'll be honest I don't know a lot about the brand new airplanes, but one think I do recall a lot of from reading accident reports is that they typically only recorded the last 30 minutes of data.

When an aircraft costs over 30 million USD, with some costing in excess or $300 million, surely being able to increase the amount of data recorded 10x or 20x pales in comparison to the costs?


texts: What passenger airplane has the lowest fuel efficiency?

texts:
What is the airplane with the lowest fuel efficiency? To set some parameters, let's limit it to the following:

Must be manufactured between 1960 and modern day.
Must be a non-military passenger airplane.
Must use liquid fuel (100LL, Jet-A, etc.)
Can be a commercial aircraft or GA airplane, but must be manned and have passenger seats. No helicopters!
Spacecraft don't count! (You know you were thinking of this)
Must be in the highest standard seat count configuration for the airplane. You cannot take a large jet like an A380, and remove all of the seats save for one!

Fuel efficiency is calculated in pmpg (Passenger miles per gallon), which is the total miles per gallon of the aircraft, divided by the maximum number of seated passengers. This does not include pilot, copilot, or any associated crew as passengers.

Please link back to credible sources, and show how you arrived at your pmpg in terms of mpg and passenger count.


texts: Will we ever see a single-engined airliner?

texts:
Given the trend in the industry to move towards aircraft with two engines, could it ever occur that we see an aircraft manufacturer develop an airliner with just one?

I'm suspecting the answer is no, given the redundancy offered by a twin engine configuration (e.g. if the independent probability of engine failure is one chance in a thousand, the probability of dual engine failure is one in a million.). I know the Virgin Global Flyer used one engine (https://en.wikipedia.org/wiki/Virgin_Atlantic_GlobalFlyer) presumably because the risk of engine failure was acceptable given the task in question.

However, if someone were to manufacture an engine with a probability of failure below, say one in 100 million, could this configuration make sense from an economic perspective?


texts: Does angular momentum contributes in lifting a helicopter?

texts:
I want to know whether it is possible to make a helicopter with blades that rotate counter-clockwise (CCW) seen from below. I have difficulty understanding the angular momentum in this situation.
As we may see in the picture below, the rotor rotates clockwise (CW) seen from the pilot seat look up. So far, the rotations I have seen. To extend this question: is it possible for a single engine airplane to have propeller rotating counter-clockwise (CCW) seen from the rear, looking in the direction of the nose (as so far, what I found is that every single engine airplane is rotating CW). As we know from physics, the angular momentum of a CW helicopter will be pointing up, and the angular momentum of a single engine with CW rotation is pointing forward. To be clearer: Is there any impact (i.e. power efficiency, etc) if a helicopter's blades rotate CCW (seen from below), or if a single engine plane's propellers rotate CCW? Of course their torques will be different, but it is not the case in my question as long as it is not affecting the performance (i.e. reduce the power efficiency, etc).

Picture source: Picture 1, Picture 2;


texts: Is there any country that requires window blinds to be open for takeoff and landing?

texts:
Does any country legally require the window blinds to be open for takeoff and landing? I'm asking about legal regulations that specifically mention window blinds, not airline procedures or general 'follow the crew instructions' regulations.

I only need one example, whether it's FAA, EASA, a national CAA or some other regulator, or an ICAO standard or recommendation.


texts:
I read a book about WW2 1 and saw a couple of planes with a giant jet engine on top of them, e.g. the Heinkel He 162 Salamander.

I realize jet engines had to have been invented before WW2 for that kind of technology to be used, so when were the first aircraft jet engines around?

1 Aircraft of World War II: 300 of the World's Greatest Aircraft. Chris Chant.


texts: In parallel runway ops, is it better to dedicate a single runway to landings, or is it best to have a mix?

texts:
Assuming taxiing is not a consideration, in an airport with two parallel runways does the airport gain capacity by:

having a single runway dedicated for landings and the other for take-offs, or
is it best to have both take-offs and landings from both runways?

Would there be other ways to divide the movements (say by class/size of aircraft)?


texts: Can I log flight time while I am a student?

texts:
If I were to obtain a private pilot certificate, would I acquire flight hours during my training, or would I have to wait until I am certificated to obtain flight hours?

If I can log hours during training, then about how many do you think I could obtain while training to earn my private pilot certificate?


texts: Is it possible to use normal headphones for passengers in a light aircraft?

texts:
I'm just finishing up my private license and am looking forward to taking some friends up in a Cessna 172.  I've invested in a nice aviation headset for myself, but, as none of my friends are pilots, they don't have headsets of their own.  Even the cheapest aviation headsets (at least that I've found) are around $100; friends going up for an occasional flight don't want to spend that kind of money, and I certainly don't want to shell out for several spare headsets.

My question is, are there adapters available so that normal headphones could be plugged into a standard 2 jack connector?  I have not been able to find any online.  While certainly not too effective at reducing noise, this would at least give my passengers some comfort and would allow me to communicate with them without shouting during these short and infrequent flights.  Worst case scenario, I could give them all earplugs, but it would definitely be helpful to have some kind of headset solution so that I'm not shouting through the sound of the prop and the earplugs and they're not shouting through my ANR.


texts: How do handling characteristics depend on flying with a full vs. an empty tank?

texts:
Modern aircraft are capable of carrying a lot of fuel to achieve extra-long range; we're at a point where nearly every pair of destinations can be reached non-stop. Carrying so much fuel imposes limits on take-off and landing weight, so the proportion of fuel to airplane weight is not negligible.

I'm wondering how the handling characteristics of airplanes change as the fuel is used up. Do the pilots feel that the airplane is lighter towards the end of the flight? Can they do faster maneuvers with nearly empty fuel tanks?


texts: What could the fuel pump failure have been that my flight experienced?

texts:
I was on an Easyjet flight (I think an A320), when mid-flight, I overheard a member of cabin crew tell another passenger there was a 'technical' issue with the aircraft, that might make us slightly behind schedule.

Naturally, I imposed on their conversation to basically ask her to repeat the issue to me in detail. She said that the 'mechanism' that transfers fuel between the two tanks had failed, and so only one tank was available.

Obviously, the flight completed without any noticeable events, but could someone explain to me what happened as I do not understand.


texts: I'm sure that all the technological advancements in various field are enabling us to create or develop stuffs which were unthinkable even few decade ago. My question is what is the current R&D stage in self flying commercial aircraft or any project in the pipeline ? Also, who is leading this concept?


texts: Does this trip count for the commercial 300NM cross country requirement?

texts:
I'm an instrument-rated PPL and recently flew (M20J) solo from NJ to Florida with one leg of 280NM and 3+ landings (not counting the return flight because I had 2 passengers).

Will this trip satisfy the commercial cross country requirement of 300NM solo when I start my training next year even though I'm not currently training for my commercial?


texts: How to log Flight Training Device (FTD) and Full Flight Simulator (FFS) time in the US?

texts: I just completed the ATP CTP Course in the US as a pre-requisite for taking the ATM Written Exam. During the course, according to the syllabus, I have flown 4 hours of B733 in a FTD (fixed-base) and 6 more hours of B733 in a FFS (motion-base). The Simulator is FAA Certified. How should I log this pilot time in my logbook, according to the US Regulations? Do this simulator time counts as total time?


texts: What do they use to de-ice aircraft and runways on snowy days?

texts:
One of the answers to this question mentions how runways are usually in need of de-icing on cold days (which makes sense), and as anyone who has ridden an airplane on a cold day knows, planes need de-icing too.

What I'm wondering is a few things:

What is used to de-ice a commercial aircraft?
What is used to de-ice a runway at a large airport?
Do the two fluids effect each other at all?  Meaning, when an aircraft drips de-icing fluid onto the runway, does it cause any interactions or problems?


texts: What does it mean when there is no ceiling or "CLR" in an airport METAR?

texts:
Here's the current METAR at KFLG:

  KFLG 210657Z AUTO 21010KT 3/4SM -SN BR VV010 M07/M09 A2961 RMK AO2
  SLP044 P0003 T10721094 410331178

It doesn't have anything about cloud layers or "CLR", but it shows what the vertical visibility is. Why doesn't it have information about the cloud layers?


texts: If a pilot license is revoked by a country's aviation authority, can the pilot still obtain another license?

texts:
There was a recent new story of a Kuwait Airways pilot that got his license revoked after an investigation into an incident on an international flight where unauthorized persons were allowed on to the flight deck.

You can read more about the actual incident here.

Can this pilot still obtain another license to fly commercially?


texts: Are airliners searched after each flight?

texts: When a commercial airplane lands at an airport, is it always searched for suspicious objects?


texts:
Can someone tell me exactly what happened on this flight? It was a brief moment of sudden drop in altitude (6000 feets) almost at the same time with a drop on engine powers. It's a drop of signal from flightradar trackers or an issue recorded in flight? Thank you!

https://www.flightradar24.com/data/flights/w63655#20da042d


texts: Are pets/animals in the cargo hold monitored inflight for any sudden medical condition?

texts: My question is more from a long haul flight POV. Does the crew do a mid-flight check etc. What if any animal/pet have a sudden cardiac arrest or some emergency medical situation, will the crew or pilots be alerted for the same?


texts: Why does the tapered part of the wing has high coefficient of lift? Like a Delta wing design

texts:
If we take a Trapezoid wing shape as an example and see that it has low  near the root of the wing and very high  at the tip. The Lift generated, however, is reversed to the that of the .
Also is there a difference in2D case vs 3D case?


texts: Can autothrust keep the plane aligned with the runway during crabbing?

texts: I'm not talking about the entire auto pilot system, but only the thrust. Because I think, when experiencing crosswind during landing, the speed of wind may fluctuate and on 3 digit approach altitudes and below, it is hard for pilots to balance the forces with counter-forces without missing the runway. Is auto thrust precise enough to balance those forces in such short distances and short amount of time, and keep the plane aligned with runway after pilot points the plane against the wind?


texts: What control inputs are required to perform a "turning-while-in-flight" maneuver in a helicopter?

texts:
My question is relatively simple and has to do with the required control inputs to perform a simple turning maneuver over a large area.
Suppose a helicopter is traveling in forward flight, straight and level, and the pilot has to alter course to circle a large area. Now, suppose the helicopter begins a slight rightward turn, while continuing to fly 'forward', and ends up semi-circling over a broad area.
I want to make the point that the helicopter is not yawing/turning on its own axis, but rather performing a turn over a large area.
The resulting flight path, if viewed from above, would essentially be a semi-circle or horseshoe shape.
This would obviously involve some rightward banking. What I want to know is this: can this maneuver be performed with only cyclic inputs, or would there also have to be pedal inputs to complete such a turn? And if it can be performed only with cyclic inputs, what exactly would those inputs be apart from rightward cyclic? Thanks in advance!


texts: Have the results of the USAF's $AVE program research been implemented?

texts:
According to this Aviation Week article from October 2012, the US Air Force Research Laboratory ran a program called Surfing Aircraft Vortices for Energy ($AVE) to test/prove that autopilot settings could be adjusted to allow C-17s to fly in formation using the wingtip vortices of the lead plane to reduce fuel consumption of the following planes. They seem to have found upwards of a 10% reduction in fuel for the following planes.

The article indicated that previous experiments involved hand-flying of the aircraft in formation which required the equivalent concentration, focus and exhaustion levels of aerial refueling and was unfeasible for long duration flights, therefore the tests proposed to incorporate the formation flying into the autopilot

Does anyone know if these auto-pilot configurations have been put into use in line C-17s or other USAF transport aircraft?


texts: How can I log simulated instrument time and approaches in a single-place aircraft?

texts: Is there a way to log instrument approaches in VMC when all you own is single-place aircraft? (or aircraft with only one pilot station - I own a Long EZ). The regs seem to indicate that I have to rent another aircraft, which seems to defeat the entire purpose of maintaining currency, as I would be logging my approaches in an aircraft of a different type, with potentially different avionics.


texts: what is the statistical risk of head rotor failure?

texts: What are the chances of rotor failure? What percentage of crashes are related to a malfunction of the rotor head?


texts: What is the procedure for an engine fire in the 737-800?

texts:
If there is a fire in one of the engines of the 737-800, what is the procedure to be followed in the following situations?

Climb
Cruising altitude
Approach

What should the pilot do in the cabin in these three situations? In the climb stage, should the plane return to the airport of origin or continue the flight?


texts: From what I know it’s measuring engine vibrations? What do the numbers actually mean? For example, 1.9 VIB:


texts: What is the map projection for FAA terminal procedure charts?

texts: What is the map projection for FAA terminal procedure charts and what are the parameters (standard parallels) for each specific airport? I couldn’t find any information with the publication information and also not on the charts.


texts: Why does lower atmospheric pressure produce higher EPR (thrust)?

texts:
Recently, I read manual about engine, PW JT8D-217A/C, and there is a chart making me so confused.

Manual show the reference table tells you what number, EPR, is normal in specific temperature and atmospheric pressure.

(Click to enlarge)

We all know EPR can be related to engine thrust.

I thought higher Atmospheric Pressure meaning higher air mass density, so EPR should be higher.

At lower temperature making higher efficiency (Higher EPR) is quite easy to understand.

But according to the manual, lower Atmospheric Pressure can produce higher thrust when temperature is constant.

Also when temperature is higher than 102.2F, the EPR doesn't change anymore in different atmospheric pressure.

Why is that?


texts: Is it possible to control the direction during auto-rotation?

texts: Is it possible to control the direction during auto-rotation, and how does it work?


texts: How do I convert true heading to magnetic heading or the other way around?

texts: Is there a method by which the conversions can be achieved on the fly by using a mathematical formulae and not using specific area charts?


texts: How close would another aircraft have to fly to warrant a sudden big altitude drop to avoid collision

texts:
This morning I read that mulitple people got (light) physical injuries after a passenger flight had to forcefully drop its altitude quickly in order to avoid collision with a fighter jet. The news article stated that it was flying at a  "safe" distance of 1,000 metres for a visual inspection, and that there was no danger at all. Although some other sources state that the distance was only down to a hundred meters
To me (someone who knows next to nothing about flying) a distance of one kilometer sounds pretty close for two planes to fly at (seeing the speeds planes travel at). The article states that this is "in accordance with international standards", but from this answer I understood that 3 to 5 miles (4.8 to 8km) is the general distance. However that answer also states that in a "Military Operations Area" this may not be the case (which this area might have been in, but then I feel like it wouldn't have mattered that it was "in accordance with international standards", as those don't apply then anyway).
That said, are there any alarms or warnings that start going off when another aircraft gets so close to warn the pilot of possible collision, or is a pilot trained to undertake action based on what his/her visuals/flight data are telling him/her at the moment? (I have read before that measuring a distance by visuals is very hard in open air due to there being no reference points, so I think it is unlikely that a pilot would act up on that alone). What is the protocol for a pilot suspecting the possibility of a mid-air collision?

It seems that this incident is also a bit of a political issue. I am not trying to discuss if everyone took the right actions here, and what the intentions of the parties were. Just interested in the protocol behind making such a drop.


texts: How do I find the floor of controlled airspace on sectional charts?

texts:
So, I understand finding floors and such when seeing something a fraction like 45/10 or 39/SFC, but I've been reviewing and gotten a couple of questions that look like this:

What is he floor of the controlled airspace overlying the Coeur D'Alene Airport?

The answer is "At the surface" but I can't figure out where it says that?
The second question said this:

What is the floor of the controlled airspace overlying the Sandpoint Airport?

The answer is "700 feet MSL". Cant find that either.


texts: What is this plane and what are the rockets on the back used for?

texts:
While reading this question I saw an image of a plane marked as a US Marines plane of some sort with thrusters or rockets of some sort attached to the sides just past the CG. What plane is this and why are the rockets there?

Image:


texts: Why does the stagnation point on airfoil move with the angle of attack?

texts: What is the physical explanation for the reason the stagnation point is where it is? And, why does it move further down the lower side of the airfoil with an increase in angle of attack?


texts: Are there any current projects/plans for a VTOL passenger airliner?

texts:
I was very surprised to see there's a seemingly underway project for a VTOL "business aircraft" that seats a few people.

http://xtiaircraft.com  , https://www.startengine.com/xti-aircraft

They assert they've done a 65% scale test.

I realize historically there have been a couple military transport-sized VTOL aircraft, and there's one or two small ones today.

Is anyone contemplating a regional airliner or even full-size airliner VTOL concept?


texts: Would it be practical that nuclear-powered seaplane (only flying low over the sea) or hovercraft can be an alternative to cargo plane or ship?

texts:
Would it be feasible that nuclear-powered seaplane (only flying very low over the sea) or nuclear-powered hovercraft can be an alternative to cargo planes or ships? The aircraft speed can reach 200 mi/h like a propeller plane and the container-sized Small Modular Reactor will be possible. So goods could be shipped from China to the US within a week at a relatively low price.
It may be a competitor to cargo planes or ships.

The flying height of this aircraft is only one or two hundred meters.
Flying only over the sea and can landing on the sea.
And the speed is low. It can be safe enough.
Container-sized Small Modular Reactor can be under 100 tons.

After @GdD commented, I got this Ground-effect vehicle.
Edit:
Would fuel-cell-powered Ground-effect vehicles like Boeing_Pelican be a competitor to cargo planes or ships?
Comments
I'm a Chinese guy and I'm interested in amateur radio and always watching some videos on YouTube. Recently I've watched a video about introducing some cheap handheld radios made in china. The YouTuber mentioned that waiting for the shipping from China for 6 weeks. So I thought there's maybe a demand for Speeding up the shipping at a relatively low cost. And so I think the nuclear-powered seaplane may be a choice in the future.


texts: What are the opimum values of Cl during descent?

texts:
Statistical Analysis of A320 aircraft shows the Cl values to be as under: cl_value. L is assumed to be 0.5*MaximumLandingWeight of A320 as the Aircraft is about to land.

The Units used are: Flight Level(feet), rho(lb/feet^3, V(feet/s), for the sixth column, 1/2(rho.V^2.S.)

The cruise Cl values are as under:

When compared to cruise the CL during descent is very small. Is this an acceptable result?


texts: Why are landing fees at large airports based on weight?

texts:
KORD airport for instance charges domestic vs international arrivals differently.

I could see that this may have something to do with imports/taxes/tariffs etc, but why are the landing fees measured in \$ per 1,000lbs?


texts: What's the wisdom of attaching an aircraft lift strut to a wing spar utilizing a single eye bolt vs the common two plate or strap method?

texts:
in the enclosed picture are three examples of types I'm speaking of.  In the top picture, the lift struts are attached via a single eye bolt.  The eye bolt is obviously vertical through the wingspar
I looked at the rudimentary engineering drawing elsewhere on this site showing the forces acting on the wing spar, and get that the wingspar is tending to make an S curve.  Let's assume that the wing spar in question has an internal sleeve doubler to effectively increase wall thickness to resist compression and prevent the collapse of the tube.
In the middle drawing, the most common method method. Two straps fore and aft, attached via a bolt horizontally though the spar. I have an elementary understanding that this second, commonplace method puts drilled holes through what I believe is the "neutral axis" of the spar.
finally, the bottom illustration of the "texas parasol" type of fitting.  It shares a commonality with the eye bolt in that there are holes drilled through the compression and tension axis vertically through the spar and attaching a u shaped bracket to the bottom of the spar into which the lift strut is through bolted.  Two holes, albeit smaller in diameter than the single but larger hole of the eye bolt.


texts: When do pilots disconnect the autopilot on an ILS approach?

texts:
In clear weather, when do pilots disconnect the autopilot, if the plane is flying an ILS approach and the autopilot is in "approach" mode (tracking both localizer and glideslope)?

Would the answer differ significantly in different planes, for example Boeing 777 vs Airbus A320?


texts: Has there ever been a strategic bomber raid completely wiped out?

texts: Question in title. All them seem to be heavily damaged but with half surviving at least. Cant find any that were wiped out.


texts: What is a flying fuselage aircraft (FFA)?

texts:
I'm fond of ultralight flying and stumbled over the SF-1 Archon site.

Specifications for more details.

I found it very appealing as an ultralight and feel like flying it even though i don't have any prior experience with pusher configuration.

I have never heard of the FFA (flying fuselage aircraft) concept so far. My knowledge is rather limited to basic conventional aircraft where the fuselage is considered to neutral by design.

Can someone expand on it please?


texts: Why is there a provision of pressure setting in GPS?

texts: Some of the GPS have a provision of setting barometric pressure (QNH/QFE). How does it work?


texts: Why would a canard wing be more prone to icing than a stabilizer?

texts: Someone said a canard wing is more prone to icing than a stabilizer. If true, what would explain this?


texts: Why would a pilot ask the tower to turn the VASI off?

texts:
This past Saturday I was taking off from runway 22 at Catalina Airport (IATA: AVX) when I heard on radio a GA pilot requesting the tower to turn off VASI after requesting weather advisory.  I did not know if that airplane was on ground or in air.

As the clouds were gathering over and I am not an IFR pilot, I was concentrating on the fast moving clouds. After a while he asked for VASI to be turned back on.

I wonder why did that GA pilot ask to turn off VASI and get them turned on shortly afterwards?

On a side note, I got lucky and saw the giant Shuttle fuel tank being towed down below near LA Forum to LA Science museum; took some pictures!


texts: Where can I get information on ATC facility activity, like the number of flights handled in a month?

texts:
As a numbers/statistics geek I would like to be able to look up information on how "busy" particular airports or regions are.

I'm sure the FAA collects this data, but is it accessible to the general public?


texts: Who has final say over an aircraft flight path?

texts:
This question got me thinking... if there was an emergency situation on a commercial airliner (let's say both engines have flamed out or something) and the pilot wants to do one thing (land in the sea), while ATC insists they try to turn around and land at  the airport... who has the final say?

Obviously the pilot is the one physically in control of the aircraft, but if he ignores ATC, believing his approach is the only safe approach and ends up killing half of the passengers in the process, would he be liable for 100% responsibility since he didn't listen to ATC?


texts: How does CDI work when flying to VOR without DME?

texts:
Let's show what I mean on an example.

Flying towards a VOR (not knowing the distance), HSI course pointer pointing
   towards the VOR. Let's say the plane is really far from the VOR and we turn
   the course pointer 5 degrees (no matter what way) CDI will move to one side
   (far because of the distance). If the plane was close to the VOR and we turned
   the course pointer 5 degrees CDI would not move as much (or should not because the
   deviation is really small).

based on this example CDI needs to know distance from VOR to work properly, yet it works without knowing the distance. How?

(If I'm wrong about something, quickly correct me)


texts: Why does ETOPS not apply to older 4 engine aircraft?

texts:
This is a follow-up to my previous question: What is ETOPS and how does it work?
There is a related question here, but it does not specifically answer this new question.

Facts:

Since February 2015, all new aircraft are required to get ETOPS
approval to fly ETOPS 180+ routes. Source.
The 747-8 has ETOPS 330. The 787 has ETOPS 330. The A350 has ETOPS
370.

Why does ETOPS not apply to the 747-400?


texts: Is there a 'common courtesy' distance that should be complied with when initiating contact with ATC for class D airspace?

texts:
Some background: I'm a student pilot preparing for an upcoming stage check involving XC diversions and have been trying to visualize different scenarios of what I'd need to do when diverting. One case I was thinking about is if you're flying, say, directly above class D airspace (in this example, maybe 3500 ft) and intend to divert there, is it considered acceptable to call the tower while directly overhead, or are you expected to be further out laterally before making an initial call?
I apologize if this is a pretty unusual question, but I want to make sure I'm not violating any unspoken rules.
To illustrate what I mean, assume I want to land at KLGB. Should I call overhead (red dot) or is it advised to get some lateral distance first (to blue dot) and then call?


texts: What should a pilot do in this lost communication scenario?

texts:
As far as I study, when a pilot faces a lost communication problem, the pilot should consider MEA (Minimum Enroute Altitude, Expected Altitude, Assigned altitude) for altitude and AVEF (Assigned heading, Vector, Expected route, Filed route) for route. I am confuse about what V (Vector) means.

For example, I have filed:

  DVT 1 departure->PHX VOR-> V105 ->DRAKE(PRC VOR)->V257->BISOP->GRAND
  CANYON Airport

I got a clearance like this:

  555AZ cleared to Grand Canyon Airport via DVT one departure PHX vor
  vector to Drake Altitude 10000' Frequency 120.7 Transponder 3435.

However, my communications fail before I arrive at PHX VOR. In this situation, A (assigned) is [DVT one departure->PHX VOR-> DRAKE]. What about V (vector)? Is it DRAKE? Or if not, how can I manage this situation? I think I should go to PHX VOR via DVT one departure. When I arrive PHX VOR, I go to DRAKE (PRC VOR) directly then go to fly as I filed. Is it correct? If not, could you let me know?


texts:
During a normal flight at cruise speed and altitude, amid the delicious airline meal and the enjoying a latest movie, all of a sudden the seat belt sign turns on.

Then a few seconds later we enter turbulence, grab a hold of that half-finished soda cup and wait patiently for the bumps to be over while looking out the window.

So, how exactly do the pilots know that the airplane is about to enter in an air pocket which will cause turbulence?

... or does it happen like this?

I have already gone through the excellent answers here and here.


texts: Would one fighter pilot know that another's mask is not on?

texts: I admit, this comes from the original “Independence Day” movie from 1996, but during the first dogfight scene one of the characters claims they can't breathe and takes their mask off.  Another character tries to order him to put the mask back on.  I assume that he couldn't just look into the other person's cockpit.  Is it possible in such a scenario to know that another pilot isn't wearing their mask?


texts: What are the relations between stability, controllability and maneuverability?

texts:
As preparation for my CFI checkride I have been trying to understand aerodynamics very well. One of the things I’m struggling with is stability

If I have a stable aircraft, this means is less controllable and less maneuverable, right?

Do this means an F-16 is poorly stable but very controllable and maneuverable? And a Cessna or a B737 are stable with less controllability and maneuverability?

Thanks for your help guys


texts: Why could these aircraft not prevent total hydraulic failure?

texts:
Then have been three incidents (UAL232, JAL123 and DHL 00-DLL) where damage to an aircraft resulted in complete loss of hydraulics. Only one of them managed to make it down safely using differential thrust. Each plane was from a different manufacturer. All three aircraft had triple or quadruple redundant systems. This seems like plenty of redundancy, but the Achilles heel is that, regardless of how the systems are piped around the aircraft they all have to converge at each of the control surfaces.

My question is why did damage in one part of each hydraulic system result in loss of the entire system? For example in the DHL incident the left wingtip was damaged with all three lines. Is there not a way to isolate that wing and cut off hydraulic flow to protect the integrity of the rest of the system? You would lose control surfaces on that wing, but still have elevator, rudder and the other wing. Do any aircraft have a way of preventing this?


texts: Why aren't bird radars placed on the front of commercial aircraft?

texts:
Unfortunately, my skills and understanding of radar and the like are very limited, but if somebody could enlighten me why there is no such thing as a dual bird/weather radar to switch to?

I've understood there there have been some (successful) attempts with ground station. It would add weight, but i'd guess that perhaps would be offset for some time by a single ruined engine.


texts: What is that pitot-like device under the left wing of the Cessna 152?

texts:
Source: tkaviation.net

I suspect it's related to the fuel system, but it's only found on the left wing (see the yellow circle, not the pitot-tube). I haven't been able to find the right keywords to find anything about it.

I'm hoping to know its function and how it does it.


texts: What is the equivalent of Hobbs and Tach in a Jet or Turbine Aircraft?

texts: As a piston pilot I am only familiar with tracking hours for my pilot log book and maintenance log book using the Hobbs and Tach times.  Can someone tell me what the equivalent is for a Turbine and for a Jet?


texts: When do I execute a missed approach on a LOC approach when I can't identify the MAP?

texts:
According to AIM 5.4.21(b):

  When an early missed approach is executed [...] fly the IAP as
  specified on the approach plate to the MAP at or above the MDA or DH
  before executing a turning maneuver.

Hence if a pilot decides on a missed approach, he needs to wait until over the MAP to execute any turns on that procedure. One can only assume that is meant to prevent a climbing turn into a nearby protected airspace.

The following scenario puzzles me.

A pilot executes a LOC approach with a missed approach consisting of "Climb to 1000' then left climbing turn to 5000' direct to..." Sometime after the FAF the cockpit timer breaks. The MAP can no longer be identified by time. The pilot immediately starts climbing to 1000'. But when to start the left climbing turn to 5000'?

The aircraft does not have other equipment that would positively identify the MAP, when is that pilot required to begin that turn?
What if the aircraft has a DME? Is the pilot allowed to identify the MAP by distance rather than by time?


texts: How do you calculate the range of a VHF transmitter that is on-board an aircraft?

texts:
I'm trying to calculate the range of a VHF transmitter on an aircraft output power 50W, frequency 130MHz, and reciever sensitivity of -100dBm.

The calculations I have made give me ridiculously high numbers in the regions of thousands of Kilometres. The formula I used for this is as follows:

Is there perhaps a different formula that I am not aware of?


texts: What VFR cruising altitude should be flown to the west below 4500 feet?

texts:
This is similar question to this question, but different scenario.

Let me describe the situation:

I am at KDYL in class G airspace. Accroding to ATIS the clouds are at 4700 scattered. I am going to fly west. I would like to fly below clouds. I will need to have 500 feet clearance below clouds in class E, so it is going to be 4200.

Do I have to comply 91.159? What altitude should I fly? Can I fly 3500 west in my scenario or I have to descend below 3000 and fly any comfortable and safe altitude?


texts: Why in the Seneca 2 the Rated Horsepower are higher at 12000 feet than at sea level? (215Hp at 12000feet, 200Hp at sea level)

texts: Reading the POH I found that the Rated Horsepower at 12000 Feet are higher compare to sea level. I have in the past studied the back pressure of the exhaust gasses but I cannot completely understand how it works.


texts: What is it called when an airplane has to circle because it can't land?

texts:
Sometimes, a plane is required to circle around an airport repeatedly because for whatever reason, it is not able or permitted to land just yet.

This state in which a plane is stuck in the air in this way has a name, what is it?


texts: Is it necessary to switch from VFR to IFR when using ILS approach?

texts:
I have flown at an airport and asked for vectors for an ILS approach in VMC for practice. But the controller refused to give me vectors and told me that I could only have a visual approach.
I got the official answer from our authorities (Ukrainian State Air Traffic Services Enterprise) that it is necessary to switch from VFR to IFR (!) to make ILS approach. But I think that no one can prohibit VFR pilots from using additional guidance, like an ILS.
Here is the answer from UkSATSE:

At your request from 07.05.2021, we would like to inform you that the approach to the instrument landing and guidance for such an approach is performed during the flight according to the rules of instrument flight (IFR). When performing a flight according to the rules of visual flights (VFR) and the need to perform a landing approach for ILS, it is necessary to switch from a flight from VFR to a flight for IFR.

Do you have any idea how we can prove that using an ILS is not prohibited for pilots when flying VFR?


texts:
According to my research, a pulsejet's thrust grows as the airspeed increases. Most pulsejets require no moving parts which makes it easier to manufacture them. They are also very lightweight which can have some great effects on aircraft.

They are very slow at zero airspeed but very fast at high airspeeds. Therefore you could simply have a normal jet engine to power the take off and then switch after take off to the pulsejets.

Here is an example where I've labelled a DC-10 of what a pulsejet with jet engine plane could look like:

The plane would taxi onto the runway using the jet engine as power, it'd then line up on the runway. It'd then power its jet engine and take off. Shortly after take off it would switch to the pulse engines and optionally turn the jet engine off.

So why don't planes use pulsejets? Surely they would allow planes to go faster and in turn allow them to reach destinations quicker. Also the pulsejets are easier and cheaper to produce than jet engines and there lighter than jet engines.


texts: I have seen the shape of the A320s engine and for example the B737 engine, its different, I want to know why its different? is it just for designing?


texts: Why did flight attendants need to be seated early landing at Palm Springs?

texts: I took an Alaska Airlines flight to Palm Springs (PSP) and on landing the flight attendant mentioned that "this is one of the airports where we need to be seated early". Why is that the case for that airport, and what would be some of the other airports where that also happens?


texts: How is the fuselage of the Boeing 787 produced?

texts:
I am particularly interested in the Boeing 787 Fuselage because it is one of the first aircraft to carry such a high percentage of Carbon Fibre Reinforced Polymer (CFRP).

Can someone explain how the fuselage is made? I know the basics of making
CFRP which include fibre being wrapped onto in mandrel in different orientations then heating in an autoclave to cure.

However, I also know that the whole fuselage is not produced in one piece. Pieces of the fuselage are produced then joined together.

I would like to know the joining process works.
Since it is not fabricated as a single piece there are bound to be stresses on the joints. Will it effect/endanger the passengers?
What loads can it take since the joints will cause a drop in overall pressure (what is the maximum pressure if possible). I don't think its being welded together but not sure the reason.
Are the same methods used to join the wings?
Last but not least, are there problems due to the joints before and if so, what has been done to rectify these problems?


texts: What is the geoid undulation used for in aviation?

texts:
In addition of the altitude found on aerodrome information, the French AIP also mentions the value of the geoid undulation::

AIP for Lyon - Saint Exupéry (LFLL)

Geoid undulation is also found in Belgium, Switzerland, Poland, Morocco, Qatar, Sweden... AIP to name the ones that appear on the first pages of Google results.

US FAA on its side mentions the ellipsoidal height directly.

On the figure below:

Ellipsoidal height is $h$,
Geoid undulation is $N$
Orthometric height is $H$

Source

A GNSS receiver determines the ellipsoidal height $h$, and can display the orthometric height $H$ by adding/subtracting $N$ from grid values embedded in the device.

Is there any use of $N$ in aviation? In the cockpit?
Are the values of altitudes found on aviation charts equal to $h$ or to $H$ or something else? Does 821 ft expresses $H$ or $h$ for this aerodrome?

Note: As visible on the figure, the vertical direction determined by using $H$ is different than the one determined by using $h$, and if an aircraft is 35,000 ft above the ARP of Saint Exupéry, this gives two possible horizontal positions, which for aircraft can be very distant.


texts: Why aren't the canards used as airbrakes on the Tupolev Tu-144?

texts:
The Tupolev TU-144 uses retractable canards to stabilize the aircraft while starting and landing. On this picture you can see them very well:

Source: AirlineFan.com Copyright: VOLPATI

It doesn't have reverse thrust and air-brakes, and relies purely on very strong wheel brakes. Wouldn't it be possible to rotate the canards by 90° (after touchdown) in order to create a very large air-brake? I don't think it would need too many modifications to the current form of the canards.


texts: What is the permissible deviation for a pilot to stop the aircraft when guided by AVDGS?

texts: As per ICAO Annex 14, table 5-4, the permissible deviation for AVDGS is 500mm at stop position, which is the design requirement for AVDGS unit.  I would like to know what is the permissible deviation for the pilot to stop the aircraft when guided by AVDGS, specifically, how far he is permitted to go after the stop signal?


texts: Can I fly from the UK to Spain on an NPPL(A)?

texts: I have a UK-issued NPPL(A) with microlight rating, can I fly my own aircraft to Spain on this?


texts: What's are the advantages of having the pilot in the cockpit?

texts:
Instead of a pilot in the cockpit, how far are we from having commercial airplanes with remote pilots (like drones)?

The remote pilot won't have any kind of space disorientation
Each of its actions would be scrutinized in real-time
pilot could be swapped every t time, so you'd always have a rested pilot
less costs, all remote pilots could have a 9-17 type of work. The airlines would just pick one in the matching time zone
the cockpit could be converted into a 1st A class space

Is there any situation where the pilot needs to feel the airplane, maybe not to override the information from instruments, but to complement it?

I'm aware that this might be a big no-no for some passengers, but how far are we of implementing this in a cargo airplane?


texts: What kind of microphones does aviation use?

texts:
Do they use the dynamic ones or cheap ribbon ones? Also why are these microphones so small?

I guess they dont use condensers. (I am yet to see an 3.5mm jack (which is used both on the C172 and the B747) that can supply 48V phantom power to the one of those)


texts:
The following image, from the Qantas Heritage Collection (via aussieairliners.org), shows the flight crew inspecting the 'Pod-Pak' prior to departure:

Based on the angle of their heads, I'd assume it's the engine-looking device to the right of frame.

Also, what are the rocket engine-like tubes at the left of frame?


texts: What does a typical discovery flight consist of?

texts: I've been considering taking up flying as a hobby and have been looking into flight schools around me. One does offer an option of a discovery flight but upon contacting them they really didn't pass along to much information on what it consist of. Could someone here kind of give me an example of what a discovery flight might consist of and help me know what to expect. Thank you!


texts: Why are the wingtips of sailplanes painted red?

texts:
Modern (plastic) gliders are painted white (I suppose for thermal reasons), except for some shapes on the fuselage (generally blue or red, but it seems the color does not matter). And the aircraft registration is dark, I suppose for maximizing the contrast.

Now, for the wingtips I noticed that there are two possibilities:

white (nothing special)
red marks

My question is: Why red? Is there something special that is preventing the wingtips from being painted in another color?


texts: Why does the NTSB release transcripts of Cockpit Voice Recordings, but not the actual recordings?

texts:
From what I have read it is illegal for the National Transportation Safety Board to release Cockpit Voice Recordings, while they are allowed to release its transcripts.

From AirDisaster:

  It is illegal for the National Transportation Safety Board, who regulates these recordings, to release them to the public.

From NTSB:

  The transcript, containing all pertinent portions of the recording, can be released to the public at the time of the Safety Board's public hearing.

Why? What's the issue with releasing Cockpit Voice Recordings?


texts: Which airports in Ireland use Surface Movement Radar?

texts: I know that Dublin uses SMR, but do any other airports in Ireland use it?


texts: Is it okay to divert to another airport in IFR lost comms situations?

texts:
In the event of lost communications, FAR 91.185 allows pilots to divert to a nearby airport if they encounter VMC conditions en route to their destination. But what if IMC conditions persist? Are they legally allowed to divert to another airport, which is not designated as the alternate airport in the flight plan, and shoot an approach to land? Doesn't that conflict with the regulation requiring pilots to follow "last assigned, last vectored, EFC route, route in the flight plan" in order?

I ask this question because I came across this phrase in my study material called Everything Explained (p.82): "Do not continue on to your destination if there is a suitable airport for you to land at, unless you're just minutes from your original destination."


texts: How is optimal Glide Path Altitude calculated?

texts:
Good day,
On a PPL checkride quite a while ago I got asked "if you are 10 miles from the airport how high should you be for a 3 degree glideslope?" Can someone run me down on how to do the math to figure it out quickly?


texts: What is the purpose of this aileron trailing edge strip?

texts:
See the following photos of the LH aileron of a Beechcraft King Air B200:

Source: own work

Source: own work

As seen in the above photos, the Beechcraft King Air B200 has what I would describe as a bulged trailing edge strip on both ailerons. These strips are roughly centered in the span of the aileron, and in the case of the LH aileron are located outboard of the trim tab.

In figure 57-50-00-06, the Beechcraft B200 IPC lists these as -320 and -325, calling them the LH and RH trailing edge strips:

The King Air 200 has the same trailing edge strips, which are listed as -70 in fig  57-70-10 of its IPC with the same part number as on the B200.

I do believe the King Air 300 series also has these strips, though I am not certain. I don't believe the King Air 90 has these, but again, I could be wrong.

I have asked many King Air pilots and maintenance crew if they knew what the purpose was, with no definite answer. The best answer I have recieved was a tentative suggestion that they might be for something like dampening control buffet.

Does anyone know the purpose for these bulged aileron trailing edge strips? Does anyone know of any documentation for their purpose? Do similar control surface design feature appear on other aircraft?


texts: What really causes a low-pressure gradient over the top of an aerofoil?

texts:
As air flows over the top of an aerofoil the pressure drops. Compared to the high / normal pressures on the underside, a pressure gradient is formed with higher pressure further above the wing. You get:

less pressure = less particles = less density

This sketch summarizes what I know so far:

My questions are:

Does lower air density above the wing mean the air weighs less compared to the weight of the air underneath the wing? If the difference is negligible then it's OK, we can forget it.
What forces act on the air particles causing them to speed up?


texts: What is the aircraft loss-rate from Nimitz-class aircraft carriers?

texts:
What is the aircraft loss-rate from Nimitz-class carriers?   That is, what proportion of sorties result in the loss of the aircraft for reasons other than enemy action?

I was prompted to ask this after the Russian carrier Kuznetsov lost two aircraft in the space of a couple of weeks.


texts: Will optimising the weight distribution of a commercial flight save fuel?

texts:
Since the centre of gravity must lay in a certain location, I'm wondering if it would save fuel if it lays exactly in the right spot?

Let's assume that you have an A320 and weight distribution is fine (within tolerance). If ballast is shifted until COG is located at the perfect location, would you save fuel? How much would that be?


texts: I'm a software engineer that's interested in decoding raw FIS-B data. DO-267A (E.1) points me at http://fpr.tc.faa.gov/default.asp as the location of the FIS-B Product Registry. However, I have been unable to connect to this website the last 2 days. Does anyone know if this is still the correct site? Is the data hosted anywhere else?


texts: Any G650 operators seeing "smoking" (i.e. they leave a dark trail on the fuselage) rivets on the fuselage at various locations?


texts: Who is the pilot in command when the pilot in command is resting?

texts: On long-haul flights, there are extra pilots on board so that the flight crew gets a chance to rest. When the pilot in command gets relieved and goes to the rest area, who is legally in charge of the airplane? Is the PIC role transferred to one of the pilots in the cockpit, or is the person who was relieved still ultimately in command? (I'm especially interested in what happens if the relieved PIC feels that the crew is mishandling the aircraft and wants to come back and take control).


texts: Are there any incidents caused by rudder failure in Military jets?

texts:
Based on this question about the rudder position of the F/A-18 Fighter Jet.

Quote from the user Rhino Driver:

  The logic has its limits though and if the pilot exceeds 14 AoA in a landing mode (flaps half or full), the FCS may accidently depart the jet. This is obviously bad 200 ft above the ground.

  As stated before, there are times when the rudders may suddenly fare themselves which can have devastating effects during the final portion to land. Rudder failures are serious problems and should be treated as such.

Are there any known incidents where the pilot (as example) exceeded 14 AoA in landing mode and the FCS accidently departed the jet?

The FCS has to play a certain role in the incident (like in the example) or like the incident No. 3 from the user aeroalias.


texts: Why weren't SA-On GPS units updated to become SA-Aware?

texts:
SA = Selective Availability (gps.gov)

SA-On and SA-Aware are widely used in current air transport aircraft (...)

GPS that behave as if SA is still active (SA-On)
GPS that behave as if SA has been deactivated (SA-Aware)

I was under the impression a software update would turn SA-On to SA-Aware. But that's not the case. Why is that? I'm asking about transport aircraft. I wasn't able to find an answer, and to add a complication, ICAO says:

GPS system with SA activated ± 100 Metres (no longer relevant because SA is deactivated)

If it's "no longer relevant", then why is there a difference in the preflight check rule (shown below)?

Top quote and slide: FAA Briefing ADS-B Rules and Airspace, Sep 2017, via icao.int (PDF)


texts: The YF-23 was one of the most stealthy aircraft of all time and had a range capability of 2,000 miles (that's more than some airliners can travel) but never entered service. The F-22, has high maneuverable, and is considered to be the second option compared the to YF-23 stealth and speed. So why did the YF-23 never enter service? Image source: NASA/DFRC


texts: Why can't planes use only flaps in the tail section instead of stabilizers?

texts:
I imagine plane having only four flaps in the back (one on top, bottom, left and right), similar to ailerons but longer and narrower. They can open from the fuselage to correct the plane's yaw or angle. I predict that this would increase efficiency of the plane since there's no drag from the horizontal and vertical stabilizers.

Can this design work?


texts: Why open up the window shades before takeoff and landing?

texts:
On commercial airlines, I've noticed that the flight attendants always ask everyone to open up their window shades before landing or takeoff.

I've always wondered why this is. Is it something to do with the mechanics of the plane? Is it some kind of passenger-comfort thing?

I can't imagine what difference this act makes, but the attendants seemed really insistent on it. :)


texts: What prevents a Machmeter from being the standard airspeed indicator?

texts:
Airspeed is more accurate when displayed by a Machmeter than when displayed by an airspeed indicator. It isn't affected by ambient temperature / density changes. It is still affected by position error, hence it must indicate something between IAS and CAS.

Source, source

What does prevent to have a Machmeter scale both in knots and Mach numbers, and use the Machmeter in place of the airspeed indicator, as the standard airspeed instrument?

Such instruments exist:

Source (From FAA Airplane Flying Handbook)


texts: Were there any successful flying machines that did not rely on Bernoulli's Principle?

texts:
One of Leonardo da Vinci's flying machines appears to be a giant auger.  This design would not have exploited Bernoulli's Principle, but rather used the blade's rotation to push the air below it down to keep the craft airborne.

Image credit: Wikimedia

Were there any flying machines built like this that actually got off the ground?

EDIT: So maybe I have Bernoulli misunderstood, judging from the discussion.


texts: Which design method is used for super critical airfoils?

texts: How is an Airfoil categorized as super critical or not super critical? What are the ways to design a super critical airfoils?


texts: Are there locations/altitudes with minimum speed requirements?

texts:
For example, a slower aircraft operating on the North Atlantic Track System would have an operational impact on surrounding/overtaking aircraft as well as potentially increasing ATC workload to ensure separation.

So, are there any formally encoded minimum aircraft speed/performance requirements based on operational environment?

(Maximum speeds are covered in this question and the topic of why aircraft aren't designed to operate at slower airspeeds is covered in this question.)


texts: Climb/Descent or vectoring in other controller's airspace without point out

texts:
I'm an ATC trainee in an ACC.

Few days ago, I handed off an aircraft to the adjacent approach control, and the app. controller made it descend and vectored while it was still in our airspace; ACC's airspace. The STAR procedure starting from the handoff point says maintain present heading and flight level.
 It was not a dangerous situation and there was no trouble, but I'm just curious about this in terms of international regulations or recommendations.

I only found this on ICAO DOC 4444

  4.3.3.1 When area control service and approach control service are not provided by the same air traffic control unit, responsibility for
  controlled flights shall rest with the unit providing area control
  service except that a unit providing approach control service shall be
  responsible for the control of:

  a) arriving aircraft that have been released to it by the ACC;
  b) departing aircraft until such aircraft are released to the ACC.

I want to know if there are specified regulations prohibiting 'climb/descent or vectoring in other controller's airspace without point out.'


texts: What is the maximum altitude ATC would deal with?

texts:
What's the maximum altitude ATC would deal with?

Any example of jets service ceiling certified for above 45.000? Commercial & Business jets?


texts: What is aerodynamic imbalance on a propeller? The most amount of hint I got was the shape of the airfoil. All I know is that it is the different thrust each prop blade produces due to different angles on each blade station. I am looking for a more in detail explanation and some examples.


texts: How does Boeing park several airplanes on a single runway at Paine Field?

texts:
On DigitalGlobe, I saw the following picture in an article, which talks about some of the best aerial shots of 2014.

Paine Field, Washington

Questions

1) Did the plane, highlighted with a yellow circle, need to reverse to line up so neatly even though it just turned (I assume). Is the turning radius really that small that it takes very little space for a big plane to change direction so quickly on ground?

2) Is there any special reason that all the planes are on one side of the runway and not centered on the markers? They all seem to be lined up towards the left side of the picture.

3) Isn't that too close when there is another plane parked so close in proximity? Provided there is ample space available.

4) Is it just that the scale of this picture, taken from a satellite, making them look closer than they really are?

5) What does that Double marking 7/91 Mean on the North East end of the small runway? usually that is a single number indicating the heading. That can't be 91, then what does that 91 mean?

6) Why are  there a bunch of planes that are about stacked on top of each other towards the bottom right of the photo, on the ramp to 29?

P.S: I know they are parked and are not taking positions to take-off.


texts:
Hi I saw this video the other day of an XFY-1 doing a vertical take-off and landing and moving left to right while hovering.

See the video Here.

After watching this I had a few questions on how this is accomplished.

How does the plane go from vertical to horizontal and from horizontal to vertical flight? Is this done by moving the elevators to their respective extremes.
How can the plane move left to right forward to back while in vertical mode?
Is this done by some sort of helicopter rotor type of contruction in the props?

I am not sure if this is the right place to ask, neither am I an expert when it comes to planes or the engineering behind them (I just know the basics).

Would love to know how this works or resources that explain this, could not really find any myself :)


texts: Is this just a generic B737 or does it have a specific name?


texts: What could cause lower torque than normal during cruise in a King Air 300?

texts: At approx FL200 in our King Air 300 we experience a vibration and notice the torque drop for both engines. The torque stays about 10% lower than normal in cruise. The vibration is intermittent and doesn’t seem to occur in the descent. All other instruments indicate normal readings including oil pressure, temps, and fuel flow. What might be the possible causes?


texts: In constant speed propeller, if i increase RPM lever from 2300 to 2500, will the Blade AOA decrease?

texts:
Assume I am flying straight and level with power setting 21 inches of MAP and 2300 RPM with TAS=100 kts, now I change my Prop lever only (MAP = no change & TAS = no change) from 2300 to 2500, since now with same power output from engine and demand for propeller to spin faster, the governor will fine-tune the pitch, now keeping the TAS same and propeller RPM increase thereby leading to fining the pitch, the blade AOA will reduce, or doesn't it?
The image given is for constant pitch propeller, is there a similar diagram for constant speed propeller?


texts: Why would smoke enter the cabin if the batteries are switched off before the APU flap closes?

texts:
In the A320 FCOM SOPs securing if the APU flap doesn't fully close smoke may occur in the cabin in the next flight

In the NORMAL PROCEDURES SECURING THE AIRCRAFT. It states that before switching off the batteries we have to wait for the APU flap to fully close if we don't and we switch offf the batteries before the flap fully closes it states that smoke may occur in the cabin during the next flight. Could someone please explain as to how smoke will occur.?


texts: What are the exact meanings of roll, pitch and yaw?

texts:
I lack some 3 dimensional understanding.

What are these angles referenced to? For example, R, P, Y all start from 0, plane is flying horizontal, then it inclines its nose by 90 degrees, moving vertical like a rocket.
Now pitch is 90 degrees, but what now determines the roll?
While moving horizontal, roll may be the angle between the normal vector of the earth's surface and the airplane's up vector.
But when pitch = 90 degrees, what is roll?

Update: Can any (yaw, pitch, roll) triple set exactly describe the attitude/orientation of an aircraft?