ERA20LA062

The pilot reported that shortly after taking off, the airplane experienced a loss of engine power so he subsequently performed a forced landing to a parking lot. During the approach to land, he thought the oil pressure gauge was in the “yellow,” and the engine felt like it was “rolling back.” During the impact sequence, the airplane struck a chain link fence, and an electrical distribution box before coming to rest. Much of the airplane was consumed by a postcrash fire. Examination of the engine revealed that the drivetrain could not be rotated during an attempted rotation by hand of the propeller. Removal of the six cylinders revealed discoloration consistent with lack of lubrication of the connecting rod journals; furthermore, the number four connecting rod was separated from the crankshaft. Removal of the accessories, accessory case, and oil sump revealed that two of the oil pump’s drive gear teeth were fractured. No visible damage was observed to the idler gear which drove the oil pump. Examination revealed the idler gear would not rotate the oil pump drive gear with two separated teeth. Examination of the oil pump drive gear indicated that the two teeth fractured in overstress under rotation. The direction of bending and shear in the teeth fracture was consistent with the direction of rotation of the gear. Given this information, it is likely that the lack of rotation of the oil pump due to the broken teeth resulted in a lack of lubrication to the engine and the subsequent total loss of engine power. The reason for the failure of the oil pump drive gear teeth could not be determined.

On December 28, 2019, about 1732 eastern standard time, a Piper PA-32RT-300 Airplane, N27GB, was destroyed when it was involved in an accident near Fletcher, North Carolina. The pilot and four passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, they had departed from Cobb County International Airport-McCollum Field (RYY), Atlanta, Georgia earlier in the day and flew to Asheville Regional Airport (AVL), Asheville, North Carolina. When he went to depart AVL for the return flight, he did a runup and everything was normal. During taxi he was following a Canadair Regional Jet (CRJ), and tower advised him of wake turbulence. During the takeoff he rotated a little early at 75 knots to avoid the wake turbulence from the CRJ. He was climbing at Vx (best angle of climb) when the airplane started to feel “sluggish.” He checked that the mixture, propeller, and throttle controls were all full forward and nosed the airplane forward. He felt there was a and initiated a turn back to the airport. The airplane felt like it was mushing though, so he elected to perform a forced landing to a parking lot. He glanced over and thought that the oil pressure gauge was in the “yellow,” and the engine felt like it was “rolling back.” He kept the landing gear in the up position and extended the wing flaps and aimed between light poles. The right wing hit something, and the airplane stopped. During the impact sequence the airplane struck a chain link fence and an electrical distribution box before coming to rest. Much of the cabin and aft fuselage was consumed by a post-crash fire. The engine had remained attached to its mount with no evidence of pre-impact fire or fire damage observed. During a postaccident examination, the drivetrain could not be rotated during an attempted rotation by hand of the propeller. Removal of the six cylinders revealed discoloration consistent with lack of lubrication of the connecting rod journals; furthermore, the number four connecting rod was separated from the crankshaft. All six cylinders oil spray nozzles remained attached to their respective attach points. Removal of the accessories, accessory case, and oil sump revealed that two of the oil pump’s drive gear teeth were fractured. They were later located in the oil sump. No visible damage was observed to the idler gear which drove the oil pump. Examination revealed the idler gear would not rotate the oil pump drive gear with two separated teeth. The oil pump, idler gear, and additional associated components were examined by the National Transportation Safety Board (NTSB) Materials Laboratory. Examination of the oil pump drive gear indicated that the two teeth fractured in overstress under rotation. The direction of bending and shear in the teeth fracture was consistent with the direction of rotation of the gear. The examination did not determine why the gear teeth fractured and separated from theoil pump drive gear. According to FAA and airplane maintenance records, the engine had accrued about 365 hours since major overhaul, which had occurred on November 5, 2013.