CdfMxTech From United States of America, joined Jul 2000, 1341 posts, RR: 25
Reply 2, posted (11 years 4 months 1 day 8 hours ago) and read 2659 times:
The Wrinkles and Buckles have an unofficial name...I think it is "Oil Canning". They are permanent (Section 46 is especially susceptable to this condition), though more noticeable at times than others. They are normal as defined by Aircraft Structural Repait manuals as long as they do not contain cracks and go through fasteners. Couple of other things as well, but can't recall.
Toni_ From Cape Verde, joined Apr 2002, 148 posts, RR: 0
Reply 3, posted (11 years 4 months 1 day 3 hours ago) and read 2544 times:
"Will these be permanent or just because of the pressure of the landing?"
These wrinkles are normal and not permanent. What you see is the rear end of the fuselage bending a bit downwards caused by the weight of the tail during that heavy landing. It shows how flexible these planes are. Same happens when a plane is on a tailjack during maintenance. These same wrinkles will appear on top of the plane.
FredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 5, posted (11 years 4 months 1 day 2 hours ago) and read 2530 times:
Those diagonal wrinkles is the way the skin of a stressed skin aircraft takes up the stress. They will always be present when there is a load on the structure, to a larger or smaller degree. Structural engineers spend a lot of time analysing them. As time and cycles build up, they often become more apparent.
I thought I was doing good trying to avoid those airport hotels... and look at me now.
A/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 3
Reply 6, posted (11 years 4 months 22 hours ago) and read 2436 times:
Tonis explanation sounds good, were I work I always noted when I was on the fwd jack that the skin would wrinkle around the jacking point and then go away on lowering, therefore they are not permanent, there are .040" skin pockets in that area so it doesnt surprise me.