Average speed of an airplane crash?

Of all the people who died in an airplane crash what is the average speed they were going?

When they died? Zero.

Yeah, it’s the stop that gets ya…

One of the real pilots on the Board can answer this more authoritatively, but most crashes happen on takeoff or landing, so the airplane is not going anywhere near top speed.

The worst civil air crash in history, at Tenerife in 1977, happened on the ground with two planes on the same runway. The KLM plane trying to take off had reached a speed of about 160 mph when it collided with the Pan Am plane.

American Airlines 1420, which slid off the end of the runway in a thunderstorm in 1999, managed to slow to about 95 mph when it hit the non-breakaway lighting standards. Injuries in that crash ranged from uninjured to fatalities.

Usually, it’s not so much the crash as the fire afterward that kills.

Take-offs are optional; landings are mandatory.
As to the OP, it can depend. A mid-air collision is probably a higher speed than a pilot trying to land during an emergency (engine trouble). Also GA (General Aviation - your private pilots in a single engine Cessna, Piper, etc.) vs. Commercial as the aircraft fly at different speeds.

Except for Voyager and such.

PSA Flight 1771 was estimated to be going slightly faster than the speed of sound when it hit the ground, but as mentioned above, most accidents happen during landing or take-off so the speed would be somewhere around 160 knots.

To extrapolate the essence of your question…

What is a fatal speed? The human body has not evolved to deal with speeds much above running speed, say 10-12 mph. In the most general sense anything above that will cause injury, anything below won’t.

More specifically, what matters is deceleration, or G forces. Stopping from 10-12 mph to zero in no less than a second is well below 1G. Again generally speaking, anything higher can mean serious injury or death.

To give you some kind of real-world air-crash example: In the Sioux City Crash (United Flight 232) during the final seconds of approaching the runway (i.e. crashing) the pilot/instructor who was in the cockpit jumpseat and working the throttles, saw that their descent rate was over 1000 feet per minute which, as he later stated, he knew, "…was not survivable" (in a normal landing the descent rate would be no higher than 300 feet per minute). He therefore ‘firewalled’ the throttles (pushed them all the way forward to maximum) to increase forward speed and therefore decrease their descent rate. It worked. Although over 100 people eventually died, if he had not done this basic physics says that no one would have survived the initial impact alone…

The vast majority of fatalities are in light aircraft and in years past.

So typical crash speeds are slow, say less than 100 mph. The median would be somewhere around there or slower.

The average (AKA mean) will be higher since the relatively few high speed crashes that happen at 300 or 1000 mph will pull the average up.

…and sometimes the burial is free…

Isn’t 1,000 FPM only 17 feet per second?

The 1000 ft/min figure (about 11.4mph) is the descent rate, not the forward speed. I don’t know much about airplanes, but I would guess that something as massive yet delicate as an airplane hitting the ground at that speed would be very bad, even though it doesn’t sound very fast. Remember that a landing airplane has a ridiculous amount of momentum, and is supposed to land on a few small wheels without either of the wings breaking off.

It was actually descending at 1850 fpm and traveling at 250 mph.

And this…

Found this discussion at airliners.net, in which the third respondent claims that 600 feet per minute is a hard landing:

That’s ten feet (from your office ceiling to the floor) per second, so I’d say hell yeah, that’s a hard landing. But if the landing gear can take that much, they can probably take a good bit more without totally collapsing; I would have guessed that a vertical speed of 1000 fpm at touchdown would be survivable, even if it meant badly damaging the aircraft (blown tires, bent wings, wracked fuselage etc.). A lovely example of a devastatingly hard (but survivable) landing here; no idea what the descent rate was at touchdown but I’m guessing well in excess of 600 FPM.

I think the problem, as has already been touched upon here, is that badly damaging the aircraft upon landing is extremely dangerous. The wiki link provided by Hail Ants said that United Airlines 232 broke apart, rolled over, and caught fire upon touchdown. About a third of the fatalities were due to smoke inhalation, while most of the rest died from one of the several impacts during the crash. Sure, a landing at >600FPM might not dash the airplane into tiny pieces, but it doesn’t need to in order to be a deadly crash.

That airliners.net poster sounds like an armchair expert.

Typical airliner descent rates during an approach are 800 FPM. The idea at the bottom is to reduce the descent rate to about 300 or less at touchdown. Inevitably goofs happen. Everybody who’s flown jets for long has essentially forgotten to flare at the bottom; something about your altitude perception glitches & you realize too late it’s time to pull. Whammo!! you hit at 7 or 800 FPM. Nothing breaks, everybody in the cabin thinks you’re an idiot, and the FA’s get top make a cutesy PA wondering if we’ve landed yet. Not a big deal. Every seasoned air traveler has ridden through one of those.

Much above 1000 you’re going to pop overheard compartments open or drop oxygen masks. And you’ll have bought a maintenance inspection. Much above 1200 something expensive might happen like blow a tire. Up around 1500 serious bad shit starts happening, like the MD80 that lost its tail* (youtube in post 14). At 2000FPM I’d expect the gear to punch up through the wings, and/or wings to fail at the roots.

UA232 in Sioux City was doing close to 2000 FPM approaching the ground when the guy working the throttles tried to “flare” as best he could with additional thrust. It worked. Barely. They still hit doing 1500ish, and with quickly increasing wing roll, so one main gear hit first and took the lion’s share of the load, duly breaking that wing off at the root. At that point a corkscrew / cartwheel was inevitable.
*That MD80 was an FAA-mandated test that all new designs have to go through. The goal is to land as slow as possible as close to the start of the runway as possible and stomp on the brakes as hard as possible to establish the true ultimate stopping capability of the aircraft. This is used to calibrate all the performance charts which are then created by adding various cushions and fudge factors to the demonstrated ultimate performance.

Needless to say, the factory test pilots goofed a bit that day. I’ve never read the mishap report but from the vid looks like they got too slow & the sink rate spiked a bunch at the end and of course they hit *real *hard.

The phrase you’ll see me use here or hear pilots talking about is “falling out the bottom of the approach”. “Falling” is right word because once it gets that far, you’re falling and that’s all there is to it. Recovery takes time and altitude you just don’t have.

The Asiana 214 guys at SFO did the same thing. https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214. The difference was they had 300+ people on board, not two. And they weren’t trying to squeeze right up to the edge of disaster like the Douglas test pilots were.

FYI in case anybody wanted to read more: Neither FAA nor NTSB websites have any meaningful data on the MD80 mishap. NTSB has the raw facts that it was a test flight and it was a hard landing and nothing further.

Asiana 214’s summaries & full reports are here: http://www.ntsb.gov/investigations/AccidentReports/Pages/AAR1401.aspx

Nothing I could find gave a precise vertical speed at impact. In their case they were so slow they’d have hit tail first even if there hadn’t been a sea wall to hit the face of. So even if vertical speed wasn’t so extreme as to break the gear if they’d been able to land on it, it’d certainly have been enough to break the fuselage when they impacted tail-first.