Questions tagged [aircraft-systems]
The essential systems found on most aircraft, including power plants, fuel systems, electrical systems, and flight instruments.
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Are fighter jets designed to be so inherently unstable that a human can't fly one unassisted?
I'm told that in order to be more maneuverable fighter jets are designed in a way that makes them impossible for a human to control without the help of a flight computer. Is this actually true? ...
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Why is air mixed with bypass air on the A/C of an aircraft?
Air is taken from the compressors, then it is cooled by the air that comes from the ram air inlet. After that, it is compressed and cooled again by an expansion turbine. When finally air is condensed, ...
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What is this device below the door of a 737 (and other aircraft)?
The other day I made a question about the External Power Hatch. Now I would want to know what's that hole below the door.
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What is a vortex generator?
I saw a vortex generator mentioned in an aircraft listing.
What is a vortex generator?
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What exactly are those openings in the bellies of many jetliners?
I have circled the areas (in yellow) under the belly of the 737.
What exactly are those?
(airliners.net)
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How does WiFi work on an aircraft?
I've noticed that when a WiFi system is set up on an aircraft, a small bulbous structure is added. What does it contain and how does this WiFi system work?
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Why do airplanes use AC electric power?
Primary electric power on larger airplanes is provided as AC. What aspects of aircraft make AC a better choice than DC?
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What is propeller / engine sync and how does it work?
In some models of multi-engine airplanes there is a switch labelled something similar to "prop sync" or "engine sync".
My questions are:
What is engine synchronization?
How is it achieved?
Why is it ...
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How do Ram Air Turbines get deployed?
I understand that most larger jets have a Ram Air Turbine (RAT) in case of total electrical failure (for instance, when you run out of fuel) in order to at least have some hydraulics and a couple of ...
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How does an alpha (AoA) vane work?
The alpha vane (also called AoA vane) is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or ...
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What is a gust alleviation system?
Reading about the 787 it says it has
an active gust alleviation system similar to the system used on the
B-2 bomber. [1]
The gust alleviation patent says:
The gust alleviation system picks ...
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How do aircraft stall warning systems work?
If an aircraft stalls, there are stall warning systems called as Stall computers. Anyone has idea how they predict that its a stall and how they raise the alarm/warning?
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Why do aircraft use hydraulics instead of pneumatics?
I was reading about how the F-35 is having trouble with the "fueldraulic" system. This made me wonder:
Why don't aircraft use pneumatic systems instead of hydraulic/fueldraulic systems?
There are ...
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What is the purpose of having contra-rotating props on an aircraft?
Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose?
Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
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What is Alpha protection?
This article states:
An occurrence was reported where an Airbus A321 aeroplane encountered a blockage of two Angle Of Attack (AOA) probes during climb, leading to activation of the Alpha Protection ...
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What is the MEL (minimum equipment list)?
What is a minimum equipment list for an aircraft? How are MEL and MMEL related? Who creates the list, and how do they decide what is on it?
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What is the difference between variable and transient bleed valves?
What is the difference between variable bleed valves (VBVs) and transient bleed valves (TBVs)? What is their range of operations? Can they be used at all airspeeds?
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What is a "Flight Director"?
What is a Flight Director, and how does it differ from Autopilot?
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How is fuel dumped in aircraft?
I have heard incidents in which commercial aircraft are required to dump fuel in event of an emergency to avoid landing over maximum landing weight. What systems do aircraft have in place to dump fuel?...
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Is it possible to fly with counterbalanced single blade engines?
Refer the image for counterbalanced single blade (Source http://www.aviastar.org/helicopters_eng/bo-103.php).
In ground school, they took us for aircraft inspection at end of our ground school ...
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Why do most single propellers have a clockwise rotation?
Why do most single propellers have a clockwise rotation (seen from the pilot's point of view)?
There are though multi-engine planes that have each propeller rotating different directions, but in the ...
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Can the wheel brakes hold an airliner in place if its engines are at full thrust?
Are wheel brakes on most commercial jet airliners capable of holding the jet stationary on a dry surface, if all the engines are given full thrust? Could doing this be potentially unsafe or damaging ...
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Is Doppler navigation still in use for civilian aircraft?
Is it possible to find an airliner nowadays with Doppler radar used for navigation purposes?
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What happens to the spinning wheels of the landing gear after takeoff, before retraction?
What happens to the spinning landing gear right after V2 on takeoff? Are they automatically or manually braked to a halt before gear retraction? Or are they allowed to spin to a halt in the wheel ...
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Why do aircraft use 400 Hz AC instead of the 50 or 60 Hz of wall outlets? [duplicate]
Large aircraft electrical systems usually use 400 Hz alternating current (AC), while common household electrical outlets deliver AC at 50 or 60 Hz. Why the difference?
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What are these spinning discs next to the throttle of the Boeing P-8 Poseidon?
The source video can be found here and the GIF is from 0:21 onwards.
What are those 2 spinning things next to the throttle ?
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How can aircraft determine true north for inertial navigation systems?
Aircraft use GPS and inertial navigation systems in combination. Sometimes INS needs alignment (i.e. to be told where it is AND what orientation it has). How can an aircraft be be aligned to true ...
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What is the technique or procedure to disable/disengage the MCAS on Boeing 737 Max 8 & 9 Aircraft?
What is the technique or procedure to disable the MCAS and manually fly the Boeing 737 MAX 8/9 Aircraft?
To clarify my question, what I'm asking is can the pilot disengage the MCAS and if so, how do ...
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Which external instruments are visible on the A350's nose section?
Most pictures of airliner's nose sections show small dark tube- or fin-shaped instruments sticking out of the fuselage below the cockpit windows.
For example this Airbus A350 shows them well:
...
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How is the actual ground speed of an airliner measured?
Do pilots have the "ground speed" information available?
If so, how is the ground speed measured? Or do they rely on GPS info to calculate it?
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Why is there a compressor in an air cycle machine?
I'm a curious high school student. Why is there a compressor after the first heat exchanger in an air cycle machine? I've read that compressing the cold air is for the cause of efficiency because ...
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Why do similar Airbus and Boeing aircraft use different flap and slat mechanisms?
Why do most Boeing aircraft and their corresponding Airbus counterparts have different flaps and slats mechanisms (747 and A380, 737 and A320)? I'm assuming a lot of these mechanisms are patented. For ...
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Is there a maximum airspeed to deploy a ram air turbine?
Is there any airspeed limit for deploying a ram air turbine? Can airspeed be determined from the rate of its propeller rotation? Could that data be used to determine altitude?
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Do lights on wingtips change color at different times of the day?
I have gone through this post which explained me why there are red lights turned on the plane but I doubt with the color code whether it's only during the environment specific conditions or its ...
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What are the pros and cons of vacuum and pressure gyros?
Inspired by this question, I would like to know what the pro's and con's of the mostly used vacuum-gyro and the less used high-pressure-gyro is.
Side-question: Are there any other ways to make the ...
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What radios are airliners / large aircraft equipped with?
I know that pilots have to talk to the tower over the radio, and apparently you have to tune the radio to the right tower frequency. I've also heard that in an emergency, you're supposed to "squawk ...
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What is a plausible scenario for aircraft sabotage for a science fiction novel?
I am writing a science fiction novel and my characters are about to board a private jet - they will be leaving Virginia and flying to CERN in Switzerland. Some factions are not happy with what they ...
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Where does the final cooling take place in the air cycle machine of the air conditioning system?
On aircraft with an ACM air conditioning, where does the final cooling take place? Is it in the ACM expansion turbine or in the ACM compressor?
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Why do flight control cables not slacken during the cold temperatures at cruise?
Image source
Flight controls in airliners have long cable lengths in between the cockpit controls and the control surfaces. For instance in the picture above: the pilot operates the yoke, which ...
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How does an Airbus aircraft connect to the Internet? [duplicate]
I would like to understand better where (physically in the aircraft) and how the Internet connection is received on an Airbus aircraft, in particular in an Airbus A380, and then how this system is ...
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Can a Boeing 777 be hacked?
All this confusion over flight 370 has me wondering if it would be possible to hack into an airplane and control the autopilot or other on-board systems in a way that the pilots couldn't regain ...
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Does a Boeing 737-800 Have a Ram Air Turbine (RAT)?
I am travelling with Thomson on a Boeing 737-800 and wondered if it had a RAT?
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Do safety-critical avionics systems run Linux?
I have heard diverse things about this. Some people claim that running Linux on safety-critical avionics systems is a very bad idea. On the other hand some people (who are rather unfamiliar with ...
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When is an aircraft required to be pressurized?
For example a Cessna Grand Caravan doesn't have a pressurization system, but a Phenom 100 is pressurized, so what are the main reasons a manufacturer has to build an aircraft with a pressurization ...
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How does the Guardian counter-MANPADS system work?
I came across this picture of a FedEx McDonnell Douglas DC-10 equipped with an anti-missile defense system.
(wikimedia.org)
According to the picture description:
FedEx became the first U.S. ...
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Why do we lean the mixture when the air become less dense?
In a carbureted engine at higher altitudes, less dense air means there is less air entering the engine. Wouldn't we want the mixture to be full rich to allow the maximum air into the engine?
I ...
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Why do most commercial airplanes use hydraulics instead of electric/servo motors?
I'm sure it's possible to use servo motors to get precise control of the ailerons, elevators or the rudder. But still, hydraulics are widely used instead.
Hydraulics do have a disadvantage that a ...
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Which is more accurate for height measurement: GPS or barometer?
I am not a pilot and have come to this site to ask a question about the measurement of height. This is as a result of the comments made as a result of a question in the Physics Stack Exchange forum "...
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What are these grilles in the passenger cabin of this 787?
Below the windows, ahead of the seat, there are small grilles. Look:
Source: Airliners.net
What are those for?
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Where are the circuit breakers on the 787?
(787 left, 777 right)
Normally found aft of the overhead panel, where are they on the Boeing 787?
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