TONOPAH, AZ, USA
N4011G
Ayres S2R-T-34
The pilot was en route back to his landing strip after night spraying when the aircraft lost engine power. He also saw flames and debris coming from the exhaust stacks. The circuit breaker popped when he attempted to turn on the wing lights so he continued the approach without lights. During rollout, the aircraft struck an unseen irrigation ditch and the gear collapsed. An inspection showed evidence of heat and blade damage to the power turbine. The fuel control adjustment was found in the full rich position. There was no evidence of FOD to the compressor rotor and stator assemblies. The engine had a hot section inspection as a result of a previous sudden engine stoppage incident.
On May 7, 1997, at 2025 hours mountain standard time an Ayers S2R-T-34, N4011G, experienced a power loss and made an off-airport, night forced landing near Tonopah, Arizona. The aircraft sustained substantial damage; however, the pilot, the sole occupant, was not injured. The aircraft was being operated as an agricultural flight by Pierce Aviation under 14 CFR Part 137 when the accident occurred. The flight originated in Buckeye, Arizona, at 1930. Visual meteorological conditions prevailed at the time and no flight plan was filed. The pilot said he had completed a routine spraying application and was en route back to an agricultural strip when the aircraft experienced a total loss of engine power. At the time of the power loss, he saw flames and debris being emitted from the engine exhaust stacks. In response to the power loss, he moved the power lever to idle, moved the fuel control to the "off" position, and feathered the propeller. He established the aircraft in a glide toward an area of open farm land and shut off all unnecessary electrical equipment. The 70 amp circuit breaker popped when he attempted to adjust the main wing lights for landing. His attempts to reset the breaker were unsuccessful and he was forced to continue the approach without the aid of wing lights. After the landing and early in the rollout, the aircraft struck an irrigation ditch and the gear collapsed. The aircraft then slid an additional 150 feet before coming to rest. The pilot notified company personnel with a hand-held radio and they responded to his location. According to an Federal Aviation Administration (FAA) airworthiness inspector who examined the aircraft, the engine did not exhibit any external damage; however, while inspecting the exhaust port, he observed evidence of damage to the power turbine. His attempts to rotate the turbine wheel by hand were unsuccessful. The fuel control adjustment was in the full rich position. The engine was removed from the aircraft and shipped to Airforce Turbine Service in Tynan, Texas, for a teardown inspection. The teardown was observed by an FAA airworthiness inspector from the San Antonio, Texas, Flight Standards District Office. The inspector reported that there was evidence of heat and blade damage to the power turbine, including the inlet guide vane ring. The damage was localized in the power section and there was no evidence of FOD to the three compressor rotor and stator assemblies. A review of the aircraft maintenance records revealed that the engine had undergone a hot section inspection on June 26, 1996, as a result of a sudden engine stoppage incident. At that time, the aircraft had a total of 13,536 hours.
the failure of the power turbine due to an overtemperature condition created by an improperly adjusted fuel control. A factor in the accident was the tripped circuit breaker which prevented the wing lights from operating during the forced night landing.
Source: NTSB Aviation Accident Database
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