Close escapes

[Boerseun]

Got to the local newspaper yesterday, and the editor runs by me at a heck of a speed, telling me there was an airplane crash. So, a few minutes later he phones, laughing his ass off. Turns out a friend of mine, Dale de Klerk, landed his plane on a car's roof.

Checkit...

Seems he came down after an engine failure, and tried an emergency landing on a seemingly quiet road. Obviously, he can't see below him (it's a low-wing plane). And he's coming down silently, seeing as his engine cut out. So he lands, and does a "perfect three-point landing", but for some reason he's like 1.5 to 2 meters higher off the road than normal. And he simply couldn't figure it out. Only because he landed on an unsuspecting motorist's roof, which was doing the exact same speed as Dale was doing upon landing! The poor guy in the car almost had a heart attack, because all of a sudden his windows exploded as the car's roof got compressed, and he obviously didn't hear anything beforehand. Only when he slowed down and turned off the tarmac, did the plane fall off the car's roof. The one wingtip got some slight damage, but both Dale and the motorist came away unscathed!

Now I want to know from you scientifical and statistically-bent nerds out in there:

What are the chances of this happening? If landed a few centimeters to the left or right of where he did, he would have fallen of the car at a much higher speed, and at a very bad angle to the road, and would have seen his ass. Also, if the car was going slightly faster or slower, there would have been problems.

This turned out to be a freak accident of note!

[freeztar]

I'd say de Klerk's calculations were pretty close, a billion to one.

I wish there was a picture...

[TheFaithfulStone]

Seconded the wish for a picture.

TFS

[Boerseun]

Originally Posted by freeztar

I'd say de Klerk's calculations were pretty close, a billion to one.

I wish there was a picture...

I got a few from the editor at the newspaper, and will post them here as soon as I can!

[Boerseun]

Let there be pics!

Dale's plane is a "Teenie", the smallest certified plane flying. He told me once that his is the only one in SA, there are a couple more but all in the States. It really is a tiny aerie.

[freeztar]

That guy looks pretty happy for someone who just had his nice Benz crushed-in.

Perhaps it's a smile of...I'm lucky to be alive!

I couldn't imagine flying a plane like that. It seems like the slightest breeze would toss it.

[eric l]

I remember seeing this done - thirty odd years ago - as a stunt during an airshow.
To make it work, the car is going a bit (1 or 2 percent I reckon) faster than the plane, so that it wedges itself between the landing gear and the road.
If both have the same speed, the pilot and the driver simply don't see each other Still, it must take a lot of practice.
The chances for it to happen by accident are practically zero.

[ronthepon]

Nuts. Out of all the scientific explanations you could give, how about the car getting magnetic somehow for the brief interval of time the plane passed close by?

If you're actually interested in finding the probability (which I seriously doubt), you could get the statistical distributions for the landing speeds for the plane, and the cruise speeds of the car.

Erm... then you could incorporate the probability of the plane being right over the car, at the correct place. That'd need the surface area of the car top (where it would be somewhat safe to 'land'), and the area covered by the plane wheels.

Then... er... maybe we could incorporate the probability of a car being at the same position as the plane at the time... um... maybe we could find the total surface area of the road, and compare it with the car. Ditto for the plane...

Then we gotta incorporate the probability of the plane getting an engine failure (for god's sake).

Should we incorporate the probability of the car driver not getting a heart attack?

Duh, I bet the total probability is still higher than that of me getting caught in the open, naked and picking my nose. (Hey, and that's possible as well.)

[CraigD]

Originally Posted by Boerseun

Now I want to know from you scientifical and statistically-bent nerds out in there…

Pretty much waving a cape in front of our bullish noses, no?

What are the chances of this happening? If landed a few centimeters to the left or right of where he did, he would have fallen of the car at a much higher speed, and at a very bad angle to the road, and would have seen his ass. Also, if the car was going slightly faster or slower, there would have been problems.

From a glance at that little “experimental” (that’s what it’d be licensed as in the US – I suspect you’re rules are different) 1-seater’s thin fuselage, and tricycle gear, I’d say the chances of it staying on a car who’s drive has either the presence of mind or bowl-affecting paralysis to not make any sudden pre or post-impact maneuvers are pretty good – it had the double security of a maingear wheel on either side of the car, and a nosewheel in front of the windshield, and the nice crinkly sheetmetal of the cars roof forming a cradle for the fuselage. Most low-wing planes, even, I’d guess, this little one, have pretty widely spaced maingear – a high-winged plane, even a 4+ seater, would likely have dropped one wheel on/one off the car, and quickly gone all sorts of wrong. The key to this one not going terribly wrong was that it seems to have put a wheel on either side of, not on, the car top.

As for the rest of the probability, it’s pretty much a matter of determining the odds of a car being on a given car-sized piece of road at the plane’s landing speed – for that little thing, I’m guessing about 60 km/hr (about 17 m/s). We’d need a lot more data to get anything like an accurate probability calculation, but throwing out a few guessumptions:

• 1 car passing every minute
• 1 in 2 cars going about 60 km/hr, not much faster (you’d never find anyone in the US doing much less than twice that speed on a nice straight stretch like that )
• An average car top length of about 2 m
• About 1 m of forward “wiggle room”
• A wild guess about how likely the plane was to not be enough left or right in the lane to plant a wheel on the car top, of about 0.5

I get a probability of , or about 1 in 1360.

Pretty long odds, but not, I think, on the order of the 1 in 1000000000 the newsfolk suggest.

Originally Posted by freeztar

That guy looks pretty happy for someone who just had his nice Benz crushed-in.

Perhaps it's a smile of...I'm lucky to be alive!

Actually, the energies of colliding with a little, bendy-crunchy airplane with almost your exact velocity isn’t too threatening. Since the wee plane’s prop wasn’t spinning, its main implement of terrible bodily destruction was out of the picture, so I’d say that even if things had gone much worse, driver and pilot would still likely have walked away (the traditional pilot’s definition of a “good landing”)

I couldn't imagine flying a plane like that. It seems like the slightest breeze would toss it.

I’m fond of ultralights, aircraft that would have had difficulty keeping up with the car, let alone landing on it, and with a tendency to actually flip over in the wind if you get out of one without someone hanging on to it and tying it down well. Next to those, this little plane looks like … a real plane (though a bit bent up )