106
votes
Accepted
Why is Python used on aircraft although it may not be certifiable?
Just because aviation developers use Python, does not mean that Python actually goes flying.
Lots of aviation development is about testing, stressing, validating, analyzing, and documenting the code ...
- 30.4k
78
votes
Why do aircraft use hydraulics instead of pneumatics?
The big disadvantage here is the loss of precision due to the high compressibility of gas compared to liquid. Because gases are highly compressible, they provide a buffer to changes in pressure ...
- 22.7k
70
votes
Accepted
Why does the mixture knob spin?
It's called a Vernier Control. It has an internal screw that is part of the fixed housing, with threaded jaws that engage the threads around the outside and are part of the knob.
When you turn the ...
- 125k
61
votes
Accepted
How does an Airbus aircraft connect to the Internet?
There are three different ways that aircraft can give internet access to its passengers, which will most likely be on at around 38,000 feet. First off, to have Inflight wifi, there needs to be a ...
- 690
59
votes
Accepted
What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system?
I think the question is basically a good one. For the 737, we set the Cruise Altitude and Landing Altitude in the controller before the flight. Then, normally, we take off, climb to that cruise ...
- 48.4k
58
votes
Accepted
What is the technique or procedure to disable/disengage the MCAS on Boeing 737 Max 8 & 9 Aircraft?
MCAS doesn't have its own on/off switch
It is a fly-by-wire feature designed to account for a particular flight regime that would not (or was not expected to be) encountered very often in normal ...
- 4,191
51
votes
Why do flight control cables not slacken during the cold temperatures at cruise?
If you look closely at your drawing you will see the cables are not really simple pull cables but really act like steel belts. That is, there is a pulley at each end and when you actuate the control ...
- 4,866
50
votes
Is this opinion on personal computer flight simulators too strict or is it actually true?
It isn't true, not as an indictment of the simulator software community as a whole anyway. It may be that your pilot friend doesn't have experience with modern simulators, let's take X-Plane for ...
- 36k
44
votes
Does a Boeing 737-800 Have a Ram Air Turbine (RAT)?
No it does not, it does not need one, there is a mechanical connection to the flight controls that can be used if all else fails.
The B737 flight controls are hydraulically powered.
There are three ...
- 61.2k
43
votes
Accepted
Do safety-critical avionics systems run Linux?
None of the avionics systems I've worked on have used Linux or any consumer-type operating system. There are a few main issues.
First is the practical. Most safety-critical avionics involve a ...
- 18.9k
36
votes
Accepted
Why doesn’t ACARS just use HF if it has better range than VHF?
The main concern is that radio spectrum is a shared resource, meaning that while you’re using it, nobody else within the range of your transmission can use it too. That means you always want to use a ...
- 27.6k
35
votes
Do safety-critical avionics systems run Linux?
The short answer is that no safety-critical avionics systems that I'm aware of use Linux, and the highest criticality systems often don't use a commercial operating system at all. However, Linux is ...
- 6,705
35
votes
Accepted
Is there a landing gear system that extends automatically to prevent belly landing?
The simple fact is that an unintended gear deployment could be catastrophic, as it has a profound impact on the flight dynamics of the aircraft (one of the reasons there are warnings for both ...
- 3,676
35
votes
Why is Python used on aircraft although it may not be certifiable?
As a software engineer who works at a defence company that develops and sells mission critical (but not safety critical) systems, I can confirm that there's a pretty even split between development in ...
- 451
34
votes
Accepted
Would a wireless fly by wire system be practical?
The fly-by-wire is absolutely vital for control of the aircraft, and the three dominating factors here are safety, safety and safety. Weight is not one of them. The fly-by-wire system is triple or ...
- 61.2k
33
votes
Accepted
Does the Antonov An-225 have an Auxiliary Power Unit (APU)?
No. It doesn't have an APU — it has two of them.
They are located close to the main landing gears. From An-225 Mriya is the world’s largest aircraft (English version):
Auxiliary power plant ...
- 3,186
33
votes
What is the artificial horizon in between the pilots for?
The standby attitude indicator was adopted by regulation in the late 60s or early 70s following an incident involving a Lockheed Electra that suffered a dual attitude gyro failure in bad weather.
The ...
- 125k
33
votes
Accepted
How do water bombers pick up water?
They scoop it up! Making contact with the water, a probe/scoop is extended, which allows water to gush into the internal tanks:
Image source: "Bombardier 415 Probe" by Wikimedia Commons ...
- 1,628
32
votes
Accepted
How do aircraft differentiate between missile locks?
Non-holographic radar systems such as those used in fighter aircraft and active guided missiles only point in one direction at a time. Normally, when the radar is in search mode, a mechanism inside ...
- 12.6k
31
votes
Is there a landing gear system that extends automatically to prevent belly landing?
It has been tried before. Piper's PA-28R and PA-32R aircraft were equipped with an automatic landing gear extension system which would automatically extend the landing gear below 85kts regardless of ...
- 71.9k
30
votes
Accepted
Why do aircraft use 400 Hz AC instead of the 50 or 60 Hz of wall outlets?
Induction motors turn at a speed proportional to frequency, so a high frequency power supply allows more power to be obtained for the same motor volume and mass. Transformers and motors for 400 Hz are ...
- 48.4k
29
votes
How does the fuel pump work in a PA-28 and when should I use it?
The PA-28 Family of aircraft have two fuel pumps, an engine driven mechanical pump that is always pumping (so long as the crank shaft is spinning) and is considered the "main pump". The ...
- 100k
27
votes
Accepted
What does the "High Alt Landing" guarded push button on the A320 exactly do?
The button raises the altitude at which the oxygen masks in the cabin automatically deploy. When landing at a high elevation airport, the masks might otherwise deploy during approach when the cabin ...
- 53.5k
26
votes
Accepted
Is it possible to fly with counterbalanced single blade engines?
Both Bo-102 and 103 were experimental aircraft, with Bo-102 more of a jig than an actual aircraft. They were used a testbed for various technologies and the single blade rotor is only one of them , ...
- 99.8k
25
votes
Accepted
Is the Fortran language still being used in aviation?
FORTRAN is not used much that I'm aware of in aviation, but it is significantly used in aeronautical engineering. I work with people that use Mark Drela's 'xfoil', 'xrotor' and 'aswing' programs on a ...
- 4,630
24
votes
Accepted
What are these elements on the back of a Boeing 737?
① Main outflow valve door
(Source)
A valve used for controlling the pressure in the cabin. Air is pushed into the cabin by the air conditioning packs, and exits by this hole. The flow can be ...
- 69.7k
Only top scored, non community-wiki answers of a minimum length are eligible