The PA-31 flight had been relatively routine except for the turbulence — occasional moderate and several tense minutes of severe turbulence. But aside from being a little shaken, everybody was OK.
It was several days later when the AME discovered the damage during a routine maintenance check: distorted exhaust shield assembly, distorted leading edge nacelle plate and both inboard and outboard nacelle skin. Further investigation revealed numerous sheared and loose rivets under the skin between the shear plate and the engine-mount bracket, and other sections of skin.
It was only after questioning the pilots that the AME learned of the severe turbulence encounter. It was fortunate that the damage had not been more extensive.
Severe turbulence is defined in the A.I.P. MET 3.7 section as: "Turbulence in which the aircraft is violently tossed about and is impossible to control. It may cause structural damage" (emphasis added by the editor).
Not only should turbulence reports be filed with ATC to inform other pilots, the encounter should also be reported to your AME so that he/she can verify that the aircraft is still airworthy for others to fly.
Originally Published: ASL 4/1996
Original Article: Reporting Turbulence Encounters