Incident
On September 29, 2008, at approximately 0853 Pacific daylight time, a Piper PA-31-350, registration N27996, executed a hard landing at Fresno, California. The aircraft was operated by Ameriflight, LLC, under 14 Code of Federal Regulations Part 135 as flight AMF 238. The airline transport pilot reported no injuries. The airplane sustained substantial damage to the wings. Visual meteorological conditions prevailed, and an instrument flight rules flight plan had been filed. The cross-country flight originated from Oakland, California, at about 0758.
Initial Response and Continued Service
The pilot described the landing as firm and noted a blown right main tire but indicated no other issues. Local contract maintenance replaced both tires. The aircraft then continued in service for two flight sequences, operated by different pilots.
Inspection Findings
Subsequent inspection by Ameriflight maintenance personnel in Oakland revealed a line of popped rivet heads on the upper surface of the left wing above the rear spar, between the nacelle and the wing fillet fairing. A close inspection also discovered popped rivet heads on the left side of the fuselage below the cabin window, with a visible gap in the skin lap.
Maintenance personnel conducted a detailed hard landing inspection and found no further damage. However, they reported that inspection of both main gear wheels and tires showed cuts and impressions in the tire sidewalls indicative of a very hard landing. The damaged rivets were replaced, and the airplane was repositioned, on a ferry permit, to the company's headquarters and major maintenance facility at Burbank, California, for further inspection. The senior training captain who ferried the airplane reported that performance and handling qualities were completely normal.
Detailed Structural Damage
At Burbank, maintenance personnel removed wing skins from the left nacelle and the leading edge of the left wing. They discovered buckling of both main spar webs between the fuselage and nacelles.