81
votes
Accepted
Why was Pan Am Flight 103 flying over Lockerbie?
The direct route you show is actually only a straight line on your map projection. The surface of the Earth is curved and the straight line between London Heathrow and New York JFK looks like this (...
- 58.3k
78
votes
What do aircraft accident investigators do in between incidents?
NTSB investigators handle General Aviation incidents that you never hear about, as well as the Commercial incidents that make the nightly news.
There are new incidents every single day.
Try reading ...
- 31k
62
votes
Accepted
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
You can find the full incident report here and this topic is touched upon briefly, but in short they had little to no time to entertain any other options but a full speed landing.
It was not until ...
- 102k
60
votes
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
Engine #2 wasn't doing its job either
Had the situation just been engine #1 stuck at high thrust, with engine 2 normally controllable, than what you describe would be a reasonable response to the ...
57
votes
Is this one of the engines from the 9/11 aircraft?
They are definitely not jet engines. They look more like electric motors or generators or blower units or something.
- 136k
50
votes
What do aircraft accident investigators do in between incidents?
It's not like you are going to call in an accident investigation team for a hard landing or a broken light bulb.
For a hard landing you certainly would. They'd just send one or two investigators, but ...
- 56.5k
50
votes
Accepted
Will the NTSB be involved in the investigation of the crash that killed the President of Iran?
In short:
For a civil use of the aircraft, pursuant to Chicago Convention, the US Government, as the government of the State where the aircraft was designed/manufactured, would be entitled to ...
- 80.8k
49
votes
How could the Helios 522 passengers have survived so long without oxygen?
To add to Daniele's answer, from the final report:
The forensic report concluded that the aircraft occupants had heart function during the impact. The report noted that this
...
- 32.7k
46
votes
Is this one of the engines from the 9/11 aircraft?
These are very large electric motors, used in HVAC plants or water distribution, probably. Or possibly main generators out of a diesel gen-set.
They are very dense and tough by design, though ...
40
votes
Accepted
Has any accident been prevented by bending or breaking the rules?
First I have to admit that I have no idea what FAA regulations said about passengers taking part in controlling an airplane in 1989, but I guess it was at least frowned upon, even if the passenger ...
- 30.5k
38
votes
Accepted
How could the Helios 522 passengers have survived so long without oxygen?
Consciousness requires quite a bit more oxygen than merely being alive.
Human beings can last remarkably long with very little oxygen, but not remain conscious. And lack of oxygen will soon enough ...
- 12.9k
34
votes
Is this one of the engines from the 9/11 aircraft?
Those are Elevator shaft motors, they're wound for high starting torque, not like most pump motors.
Here is one of the motors from 2 other angles. It's on exhibit at the 9/11 World Trade Center ...
- 615
33
votes
Has any accident been prevented by bending or breaking the rules?
The rules say to do whatever necessary to ensure safety of flight.
91.3 Responsibility and authority of the pilot in command.
(a) The pilot in command of an aircraft is directly responsible for, ...
- 16.6k
30
votes
Accepted
What happens to aircraft wreckage?
It depends on a lot of things like the kind of accident, the wreckage state, accessibility etc.
First thing to consider is that in most cases, the wreckage is evidence- so the investigating authority ...
- 101k
29
votes
Accepted
Why do chunks of aircraft debris float?
Lighter materials such as plastic will naturally float.
Composites can have large sections of honeycomb core with trapped air. Even if these parts are broken, the honeycomb is sealed against both ...
- 73.8k
29
votes
Accepted
What is a "rapid changes in gravitational force"
The TSIB preliminary findings and the BBC use "G" as a short-hand for g-force, which is not the same thing as "gravitational force". They are using the wrong terminology here.
The ...
- 58.3k
28
votes
Has any accident been prevented by bending or breaking the rules?
As pointed out above pilots may deviate from any regulation in the event of an emergency per §91.3(b).
One of the more common events is a civilian aircraft making an emergency diversion and landing ...
- 75k
27
votes
Accepted
What possible causes can there be for a crash in good weather conditions?
A few things come to mind:
Partial or full pilot incapacitation. Anything from a heart attack, or stroke, through to hypoxia could make a pilot lose control and crash. Illness does not care whether ...
- 35.7k
27
votes
Accepted
Can a piece of duct tape bring down a plane today (Flight 603, 1996, Perú)?
Yes, this can happen on all aircraft.
The static ports on the aircraft were covered with tape for cleaning, and then not removed. This resulted in contradictory flight data (mainly airspeed and ...
- 4,510
26
votes
Can this aircraft wreckage be identified?
A plane should be able to be identified by the serial numbers of the various parts recovered at the crash scene. The history of any part on a plane is documented extensively by the serial number. ...
- 5,839
26
votes
Has any accident been prevented by bending or breaking the rules?
In 2017 an MD-83 aborted takeoff above V1. The pilot was widely criticized for that, which was against a lot of rules and conventional wisdom. The NTSB report determined that aborting above V1 was ...
- 1,233
26
votes
Accepted
Is there such a thing as icing in the propeller?
For sure. Ice tends to collect toward the blade roots (the outer blades and tips are moving fast enough for compressibility heating to keep the leading edges from accumulating ice) and spinner, so on ...
- 136k
24
votes
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
From the incident report section 1.1.4:
a. At 0519 hrs during the descent to a cleared level of FL230, ECAM
messages “ENG 1 CTL SYS FAULT” and “ENG 2 STALL” were annunciated
within a short ...
- 54.4k
24
votes
Why does the autopilot disengage even when it does not receive pilot input?
The "autopilot" is a fairly basic control system. Usually it is composed of just a few components (logically speaking) like a wing-leveler, heading mode, and altitude mode. The autopilot can control ...
- 36.2k
22
votes
Accepted
What does Lion Air faking the repair of the AoA vane mean for the Florida repair shop that ceased operations?
The FAA action, while supposedly not directly related Lion Air but more to Xtra's problems with working on parts they were not authorized to work on because they hadn't demonstrated that had ...
- 136k
19
votes
Accepted
How do investigators always know the logged flight time of the pilots?
The methods that Dan referred to in his answer are valid, and might be used by investigators—the NTSB for example.
However, generally speaking the NTSB will not spend a great deal of effort ...
- 16.6k
19
votes
What does Lion Air faking the repair of the AoA vane mean for the Florida repair shop that ceased operations?
As part of the investigation the authorities followed that part through the system and scrutinized every step of the AoA's life. When they looked at Xtra they found numerous issues with the company ...
- 54.4k
19
votes
Accepted
How many parameters are stored in the flight data recorder these days?
For aircraft following FAA regulations, modern FDRs for air carriers must store 88 parameters, which are listed in 14 CFR 135 Appendix D. The previous lists are in 135.152, there were 11 parameters ...
- 3,271
Only top scored, non community-wiki answers of a minimum length are eligible