On March 19, 1999, a Schweizer G-164B (registration N3629T) was involved in an aviation accident near Bay Springs, MS. Investigators recorded the probable cause as: Internal gearbox failure and bearing failure at the intermediate gear, leading to loss of engine power. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
While maneuvering at low altitude for chemical spraying, the engine lost power due to an internal gearbox failure. The pilot attempted a forced landing, but the airplane struck trees.
Accident Summary
During an agricultural spraying operation, the pilot was maneuvering at low altitude over a stand of trees when the engine unexpectedly lost power. The pilot selected an area for an off-airport forced landing. During the landing attempt, the airplane collided with trees.
Investigation Findings
Post-accident examination of the engine revealed an internal gearbox failure. Metal debris was found in the output housing at the forward scavenge strainer. Additionally, bearing remains were recovered from the gearbox assembly. Inspection of the fuel control drive train showed that the intermediate gear had uncoupled from the dual idler gear, accompanied by a bearing failure at the intermediate gear. The oil filter and chip detector were removed and found to be contaminated with metal particles.
The findings indicate that the loss of engine power resulted from these mechanical failures within the gearbox and fuel control drive train.
Probable cause
Internal gearbox failure and bearing failure at the intermediate gear, leading to loss of engine power.