Pilot Debrief

AIR TRACTOR INC AT-602 near Allport, AR — 2022-06-01

Final reportCEN22LA228
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Date
2022-06-01
Location
Allport, AR, USA
Aircraft
AIR TRACTOR INC AT-602
Registration
N5007R
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

A partial loss of engine power due to fuel contamination from foreign object debris. Contributing to the accident was the operator’s failure to follow the manufacturer’s required airframe fuel filter inspection interval.

NTSB narrative

The aerial application airplane was loaded with chemical for application on a rice field. Immediately after the takeoff from the private airstrip, the pilot heard a “loud pop” noise from the turboprop engine, and he observed flames emit from the left side of the airplane. During the forced landing, the pilot reported that it felt like there was a “slight recovery” of engine power, but then the engine ceased producing power. During the forced landing, the airplane nosed over and came to rest inverted, resulting in substantial damage to the left wing, the fuselage, and the empennage. Examination of the airframe revealed foreign object debris (FOD) between the airframe fuel filter pleats and in the fuel filter bowl. Examination of the engine revealed contamination of the engine fuel filter and various fuel wetted accessories. The engine exhibited rotational contact signatures on the compressor turbine and the power turbine components consistent with the engine producing power at the time of impact; however, the engine power output at the time of impact could not be determined. Marks on the piston, cylinder, and blade damage indicated the propeller was operating at low blade angles with low or no power at impact. Chemical testing of the FOD samples from the airframe and the engine revealed a composition consistent with an unknown fertilizer-type material. A review of the airplane’s maintenance records revealed that the airplane was flown about 44 hours past the manufacturer’s required fuel filter inspection interval. It is likely that contaminated fuel obstructed the engine fuel filter and was injected into the engine, which resulted in a partial loss of engine power. The source of the FOD and how it entered the fuel tanks could not be determined based on the available information. It is possible that, had the operator completed the airframe fuel filter inspection within the required interval, the contamination of the filter may have been identified.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Inspect and clean the airframe fuel filter more frequently to prevent contamination.

NTSB coding

Evidence available

  • Photos
  • 18 docket documents
View NTSB final reportView NTSB docket

Docket documents18

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