On December 21, 2006, a Piper PA-28R-180 (registration N4666J) was involved in an aviation accident near Fresno, CA. Investigators recorded the probable cause as: The design stress limits of the airframe were exceeded by an unknown pilot. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
After a cross-country instructional flight, wrinkled skin was discovered on top of both wings. No damage had been detected before the flight. The instructor stated the damage did not occur during the flight. FAA interviews with recent pilots could not determine the cause or responsible party.
Incident Details
A flight instructor completed a check-out in an airplane, followed by a cross-country instructional flight. Prior to both flights, no damage to the airplane was detected. After the cross-country flight, wrinkled skin was discovered on top of both wings. The instructor stated that the damage was not a result of anything that had transpired during the cross-country flight.
Investigation
The Federal Aviation Administration (FAA) conducted interviews with numerous pilots who had recently flown the airplane. These interviews failed to reveal who was responsible for the damage or how it was caused. The origin of the wrinkled skin remains undetermined based on available information.
Conclusion
The cause of the wrinkled skin on both wings could not be established. No probable cause was identified in the investigation.