47
votes
Accepted
Why evacuate upwind?
There are two problems linked to the wind after accidents:
Inflating the slides.
Running away from the aircraft when on the ground
@DavidRicherby listed the reasons related to running away upwind to ...
- 80.9k
41
votes
Why evacuate upwind?
If there is a fire, any smoke and flames will blow downwind. If there is a fuel leak, the fuel vapours will be blown downwind, risking a fire or explosion there and potentially making it hard to ...
- 12k
30
votes
What happened to this plane during landing? Failed first time?
There are many, many reasons why a pilot might go around.
The approach wasn't stable.
The last plane that landed was slow to get off the runway, and the pilot or ATC decided that landing would create ...
- 12.8k
27
votes
Accepted
Is an autopilot failure an emergency?
It's not an emergency, but there is a significant workload increase because both pilots now have to be paying attention full time, with one watching the other flying, vs only one (watching the AP) ...
- 136k
26
votes
What could the fuel pump failure have been that my flight experienced?
The conversation may have been about fuel pumps or fuel transfer valves but the flight attendant was probably told that as a simple explanation - it would not have been the real cause.
Aircraft have ...
- 11.5k
17
votes
What can I do as a bystander on the ground if I see an aircraft above me that appears to be failing?
Brian Tusi's answer is correct in that there's probably very little (most likely nothing) that you can do right then and there to help that particular aircraft, even if your assessment is correct in ...
- 6,984
14
votes
What happened to this plane during landing? Failed first time?
It is not at all unusual for commercial planes to do a "go-around" if the landing picture is not to professional standards.
Remember that a commercial plane frequently has between 100 and ...
- 31k
13
votes
Is an autopilot failure an emergency?
I have hand-flown an airliner both sectors (there and back) on one occasion. It was 2 hours there and 2 hours back (dispatched with the autopilot inoperative) so in good weather it is not an issue. ...
- 1,666
12
votes
Accepted
Why would Boeing be under review if crew-error is determined to be the cause?
In aviation (and other safety critical areas) it's not enough to just look at the first cause of an accident, you have to look at why that mistake was made, and why that thing happened, as far back up ...
- 3,433
10
votes
Accepted
What are the different ways my alternator is failing?
If you have a voltmeter installed, a failed alternator will cause it to read ~12V (or ~24V) while a working alternator should show ~14V (or ~28V)
The voltage regulator (wired in after the alternator) ...
- 102k
8
votes
Accepted
How common is engine failure?
Engine failure is not that common. For a gas turbine engine, a press release by GE gives some data as a reference point. In 1995 they quoted various engines as having a dispatch rate of between 99.99% ...
- 4,543
8
votes
Accepted
What would a Category II ILS approach require that a Category III approach wouldn't?
If approach lights (ALSF-II) go inop when inside the FAF, it's a required go-around Cat II, because at 100' you're looking at them + the runway. Same failure during a Cat III, you can continue, ...
- 53.7k
7
votes
Accepted
Do aircraft have backup systems to trim when they don't have trim wheels?
Yes, there is a backup system available when there is no trim wheel. On the Boeing 747, the stabilizer trim has two control modules, normal and alternate:
Stabilizer Trim
The stabilizer trim system ...
- 58.3k
6
votes
What can I do as a bystander on the ground if I see an aircraft above me that appears to be failing?
In addition to the suggestions in the other comments, you might do what this guy did, because your scenario just happened a few days ago:
Pilot praises RAF Lakenheath plane spotter for saving his life
...
- 165
6
votes
What is a 'Wing Loop Fault' on an A320 series Aircraft?
Wing loop fault refers to the overheat/leak detection system running along pneumatic lines in the wings and belly. Fire loops on the engines is a different matter. The loops consist of an outer and ...
- 61
6
votes
What could the fuel pump failure have been that my flight experienced?
The usage and movement of fuel changes the aircraft's center of mass. A lot of aircraft have fuel pumps that move fuel between the two tanks in the wings to make sure one side does not get heavier ...
- 562
6
votes
Why aren't angle-of-attack data sanity-checked before being fed to other aircraft systems?
And exactly what or how are you going to ‘sanity check’ these systems? The AoA sensor is just a sensor, converting a physical position into a voltage which another piece of hardware can interpret the ...
- 75.1k
5
votes
Accepted
Do all Bombardier jets have manual reversion?
Can't speak for the Lear, which I believe has manual controls anyway, but the CRJs DO NOT have manual reversion. The RJs are designed to a technical level similar to the Boeing 767.
The control ...
- 136k
5
votes
Why was the 737 main rudder servo valve’s vulnerability to causing uncommanded reversals never discovered in testing?
After the accident the NTSB did very extensive testing on the PCU to determine the cause of the failure. In addition to the flight 427 PCU they tested new units, units that had been removed from other ...
- 28.7k
5
votes
Why aren't angle-of-attack data sanity-checked before being fed to other aircraft systems?
Most modern systems, such as those found in Air Data System, stall warning, Primary Flight Control Computers, already do bound checks on the measurement values. If an AOA measurement is outside of ...
- 11.1k
5
votes
Why do the A320’s primary flight controls have hydromechanical backups only for the rudder?
The mechanical backup is only meant to maintain basic controllability during a temporary failure of the whole fly-by-wire system. As the OP mentioned, the rudder is deemed sufficient for basic roll ...
- 11.1k
4
votes
Why aren't angle-of-attack data sanity-checked before being fed to other aircraft systems?
It is a very good question, in light of what happened with the Lion Air flight 610 crash. Caused by a single mis-calibrated AoA sensor, resulting in 189 deaths.
Single inputs into flight automation ...
- 62.9k
4
votes
Accepted
Can a 737NG still fly when every single electric run device/system is dead?
TLDR: Yes, the 737 can still fly, the gear can be lowered and one can brake after landing.
A complete failure of every single electrical system is extremely unlikely. The QRH (Quick Reference ...
- 58.3k
3
votes
What could the fuel pump failure have been that my flight experienced?
If there really was only one tank of fuel available on an aircraft that typically has two tanks filled, that would at a minimum mean that the airplane would have to fly on half the fuel that was ...
- 6,984
3
votes
Is there an in-flight built-in-test in an airplane?
The thing that separates a BIT/BITE (E=Equipment) from continuous fault monitoring is that the continuous fault monitoring simply responds to exceedances of various paramters or values outside of ...
- 136k
3
votes
Accepted
Why do the A320’s primary flight controls have hydromechanical backups only for the rudder?
The thing is your first picture is not really correct. The links from side-sticks go through the “magic” box, but the links from trim wheels and pedals don't. Instead there is a link from the “magic” ...
- 56.5k
3
votes
How do Ram Air Turbines get deployed?
But how does it get deployed? I'm interested in the triggering mechanism, as, during a complete electrical failure, there can be no electrical trigger (computer or otherwise).
Think the other way: it ...
- 759
3
votes
Can a plane fly without the vertical stabilizer?
It is not hard to design a swept-wing aircraft to fly fine without a vertical tail. For example a "Zagi" flying wing like this
will still fly ok if the vertical tip ...
- 23k
Only top scored, non community-wiki answers of a minimum length are eligible