79 votes
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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 (...
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  • 45k
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 ...
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  • 28.4k
77 votes
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Is the NTSB hostile to pilots, as depicted in the movie 'Sully'?

I think it is quite unfair to paint the NTSB investigators as villains just for the dramatic effect when nothing of the sort happened in real life. It is the job of the NTSB to investigate all ...
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  • 98.6k
61 votes
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Why are test crashes not made harder on the airframe?

If the plane crashes with high vertical speed, the decelerations involved are so insanely huge that there is absolutely no way to make it survivable. That is well explained in Even after years of ...
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  • 54.1k
61 votes
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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 ...
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  • 96k
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 ...
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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.
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  • 105k
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 ...
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  • 54.1k
47 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 ...
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  • 31.5k
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 ...
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41 votes
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Why is the FDR and CVR put into water again after a water crash?

This is actually a fairly standard thing to do with electronics that have been submerged: They are placed in water (ideally fresh, clean water) to both delay the onset of corrosion and dilute any ...
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  • 67.2k
40 votes
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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 ...
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  • 21.1k
37 votes

Is the NTSB hostile to pilots, as depicted in the movie 'Sully'?

No, they are not. The NTSB simply investigates accidents to determine the root causes of the accident and to make recommendations as to how to improve aviation safety. It has no bias nor does it ...
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37 votes
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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 ...
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35 votes
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Why does it take months, sometimes years, for the BEA and NTSB to complete aviation accident investigations?

When it comes down to it, accident investigations involve lots of coordination between many different groups, companies, and agencies, often around the world. These groups may range from helpful and ...
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  • 69.7k
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 ...
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32 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, ...
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  • 16.2k
30 votes
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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 ...
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  • 98.6k
29 votes

Why are test crashes not made harder on the airframe?

Because they wanted to analyse survivability, making the crash non survivable would have defeated the point.
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  • 31.5k
29 votes
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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 ...
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  • 69.7k
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 ...
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27 votes
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Why don't black boxes send a signal when above water?

The short answer is that when a plane crashes on land we (generally) have a pretty good idea where to look for the black boxes - there will usually be a relatively clearly defined debris field to ...
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  • 67.2k
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. ...
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  • 5,561
25 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 ...
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  • 1,214
23 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 ...
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  • 49.6k
23 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 ...
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  • 35.1k
22 votes
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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 ...
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  • 105k
20 votes

Why are FDRs and CVRs still two separate physical devices?

You probably wouldn't believe the effort needed to certify anything that flies on an aircraft. This is a multi-year process, especially if it is so much security-related as the CVR and FDR. And it ...
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