Archive for the ‘Uncategorized’ Category
One Accident that could have been avoided had the pilot rocked the wings before flight
Sunday, February 13th, 2011
A few posts back I promised to give another reason for rocking the wings during preflight but then was distracted by other aviation subjects I had in mind and didn’t get to it right away. Here then is a (true) story:
Back when there was an airport in Morgan Hill, California, a couple of guys shared a Cessna 140. One of the pilots, (we’ll call him Sam), had noticed that when he flew their 140 he had to hold right yoke to keep the wings level in straight level flight. He figured that the solution would be to “wash in the low left wing,” thereby giving it a higher angle of incidence and more lift.
In order to change the angle of incidence in the wing of a C-140, you must turn the adjusting screw on the (wing) end of the strut. If you shorten the strut it increases the angle of attack, essentially warping the wing. In this aircraft the attach point of the strut to the wing is up inside the wing, not below the wing where you can see it such as on a Citabria, for example.
Sam was not rated as an airplane mechanic – no A&P certificate – but he believed that it was a simple adjustment and so he attacked the problem. Apparently at some point during his attempts, he turned the screw the wrong way and almost disconnected the strut from the wing.
Later, satisfied that he had solved the problem, Sam did a preflight, got into the airplane, taxiied out and started his take-off roll. Just as the wings developed lift, the loose wing flew up over the airplane causing it to snap roll and contact the ground inverted. Yeow! Sam survived but I’m not sure that the partnership did.
I doubt that this type of accident happens frequently, but had the pilot rocked the wings for any of the other reasons we mentioned in our “Why it’s a good idea to rock the wings before flight” post, he could have saved the plane, and himself some grief.
I suppose that there are (at least) two morals to this story: first, it’s a good plan to rock the wings during preflight, and second, be sure to thoroughly vet prospective airplane partners!
