Primary finding
Probable cause
fatigue fracture and subsequent failure of the gear door hinge bracket.
Investigator assessment
Analysis narrative
The pilot reported that an 'unsafe gear door light' was displayed 'shortly after departing.' He recycled the landing gear. The right main landing gear did not extend. He performed several normal and emergency gear extension attempts with no success. He had several telephone patch conversations with the airplane manufacturer and flight safety. The right main landing gear could not be lowered. He orbited to burn down fuel, declared an emergency, and conducted a gear up landing. Examination of the right main landing gear revealed a fatigue fracture in the right inboard landing gear door forward hinge bracket. The door was wedged in the wheel well.
Source record
Factual narrative
On March 29, 1996, at 1733 central standard time, a Socata TBM-700, N292RG, operated by Chemrite Industries, Inc. sustained substantial damage while landing in Eau Claire, Wisconsin, with the right main landing gear in the retracted position. The commercial pilot and private pilot rated passenger reported no injuries. The 14 CFR Part 91, business flight originated in Rice Lake, Wisconsin at 1400 with a planned destination of Milwaukee, Wisconsin. Visual meteorological conditions prevailed. In his written statement, the pilot reported that an "unsafe gear door light" was displayed "shortly after departing." He recycled the landing gear. The right main landing gear did not extend. He performed several normal and emergency gear extension attempts with no success. He had several telephone patch conversations with the airplane manufacturer and flight safety. The right main landing gear could not be lowered. He orbited to burn down fuel, declared an emergency, and conducted a gear up landing. The airplane sustained substantial damage to the lower fuselage. Examination of the right main landing gear revealed the right inboard landing gear door, forward hinge bracket was fractured. The door was wedged in the wheel well. The fractured bracket was examined by a NTSB metallurgist. In his factual report, he stated "SEM inspections of the crack revealed fatigue progression features emanating from both surfaces of the mounting flange." -