Air Tractor Inc AT 602 N653LA accident near Vidrine, Louisiana

Probable cause

The total loss of engine power for reasons that could not be determined because an examination of the engine and a test run did not reveal any mechanical malfunctions or failures that would have precluded normal operation.

NTSB analysis

The pilot was conducting agricultural spray operations in a turbine-powered airplane. During turns, he noticed that the fuel pressure varied between 19 and 20 lbs per square inch, but otherwise it appeared normal. During a subsequent turn, the engine lost power. The pilot turned on the fuel boost pump and engine ignitor, but the engine did not respond, so he conducted a force landing to a rice field. During the landing, the airplane impacted several levees, and the main landing gear were torn off; the airplane subsequently came to a stop on its belly.

The pilot reported that he looked into each wing fuel tank and that fuel was visible in each tank. Two witnesses also looked into each tank and reported seeing between about 3 and 4 inches of fuel in each tank. They added that the tanks were breached and leaking fuel. The responding Federal Aviation Administration inspector reported that the tanks were empty when he arrived on scene, but it appeared that the tanks had been breached, and fuel had leaked onto the ground.

The airplane was disassembled and transported to a repair facility. An examination of the airplane revealed fuel in the airframe filter and engine high-pressure canisters. About 1 quart of fuel was drained from the header tank. No contaminants were found in the fuel.

The fuel flow meter displayed 52.1 gallons for fuel remaining and 157 gallons used. The flow meter does not have a fuel level sensing capability but subtracts the fuel used from what the user (pilot) input into the meter. The flow meter was programmed to 209 gallons at the last refueling or instrument reset. Given the pilot may have reset the meter during the last refuel, the meter would have registered a full fuel load even if the airplane had not received a full fuel load; thus, the 52.1 gallons remaining would not have been accurate.

The engine was separated from the airframe and sent to overhaul/repair facility. The engine was placed in a test cell and started and ran with no anomalies noted. The reason for the loss of power was not determined.

Text from the NTSB. Open the NTSB docket for CEN17LA165 for the full record.