Pilot Debrief

GLIMN Kitfox 2-3 near Escanaba, MI — 2015-11-03

Final reportCEN16LA035
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Date
2015-11-03
Location
Escanaba, MI, USA
Airport
ESC
Aircraft
GLIMN Kitfox 2-3
Registration
N93TG
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Approach

Probable cause

The airplane owner's inadequate maintenance and servicing of the propeller gearbox, which resulted in oil starvation, failure of the gearbox in flight, and a subsequent loss of propeller thrust. Contributing to the outcome was the airplane's low altitude at the time of failure, which precluded the airplane from reaching the runway.

NTSB narrative

While on the downwind leg of the traffic pattern for landing, the private pilot of the experimental amateur-built airplane heard a "clunk" sound from the front of the airplane; however, the propeller continued to rotate and the engine appeared to be operating normally. The pilot continued to the base and final legs of the traffic pattern and attempted to add engine power, but the engine "overreved." The airplane lost altitude as it neared the runway and touched down on the parking apron, then continued into a ditch, where it nosed over and came to rest inverted. A postaccident examination revealed that the propeller gearbox had failed in flight. All of the drive gear and propeller drive teeth were either worn or destroyed, and the gearbox drive gear displayed discoloration and heat signatures consistent with oil starvation. Additionally, there was no usable oil present in the gearbox, and no evidence of an oil leak. Although the airplane owner stated that he had added oil to the gearbox before the flight, it is likely that the flight departed with an insufficient oil supply in the propeller gearbox, which resulted in subsequent oil starvation. When the gearbox failed, the engine continued to operate; however, it ceased to drive the propeller, which resulted in a loss of thrust.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have turned earlier toward runway 36 to land safely.

NTSB coding

Evidence available

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

Docket documents9

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