View Full Version : Crash research

Bill Greenwood
10-14-2013, 11:08 AM
One of the things I picked up at AOPA summit was a magazine on Flight Safety. The part I want to pass on is specific research on crash impacts. This is not new, but some folks might not know it.
It deals with G limits that the human body can stand.
It comes mostly from Col. Stapp and his riding the rocket sled at Edwards AFB years ago where it would hit a water ditch and slow abruptly. He finally got as many as 45 g stops and survived, not without serious damage like to his eyes.
Then, after a flood hit the Piper plant, they donated dozens of ruinued airframes to NASA who then set up a swinging pendulum to crash them into the ground, complete with many sensors and crash dummies and cameras.
To summarize, the human body can live through up to 45 g in a straight forward or rearward impact. It can take up to 25 gs in sideways impact, But only about 15 gs in vertical impact.
Now this is not to say that one can survive unmarked less than 15 gs, and you might feel like Ali after a Joe Frazier fight, win or lose. But the occupants might have a chance to live. And if you can keep the impact to 10 gs there is a very good chance to survive.

So if all goes bad, and you've looked on your cell phone for an app that says, "Save my butt" without success and you must face a crash, Remember this:
1 Keep control of the plane, don't let it hit nose low or out of level flight.
2 Try to slow to your slowest Safe approach speed.
The impact from hitting at at 100 mph is 4 times that of hitting at 50 mph. Remember that most light gen av singles have a VSO stall speed of not over 61 knots, so touching down at 60 k is a lot better than faster.
3 The bad side of this is you can't stall the plane and drop it in from 20 feet up, as that is the g impact least tolerated by our bodies.
Note there are some new seats that are better at absorbing impact in this vertical way.
4 If you can hit something even a little bit soft, so that you can stretch the impact and crash zone out it can really lower the gs.
If you could hit small bushes or a cornfield for instance instead of a boulder.
And of course this presupposes that you have reasonably strong cabin or cockpit structure and good seat belt and shoulder harnesses. If you are flying without shoulder harnesses , you should get them now.
Hope we never need to test this info; but remember how well new soft walls on race tracks have vastly increased safety, just by allowing a car going over 100 mph a few more feet to absorb the impact.