Pilot Debrief

PIPISTREL DOO AJDOVSCINA VIRUS SW near Paulding, OH — 2017-12-28

Final reportCEN18LA064
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Date
2017-12-28
Location
Paulding, OH, USA
Aircraft
PIPISTREL DOO AJDOVSCINA VIRUS SW
Registration
N4JW
Category
Glider
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

The loss of engine power while the motor-powered glider was maneuvering due to the fuel unporting in its fuel tank, which resulted in fuel starvation and a subsequent forced landing on unsuitable terrain.

NTSB narrative

The airline transport pilot was conducting a local flight in his motor-powered glider. The pilot had the right fuel tank selected and was flying in a counterclockwise direction around a ground reference point when the engine began to lose power. The pilot switched fuel tanks with no improvement and selected a nearby road for a forced landing. During the landing roll on the ice-covered road, the glider's left wing impacted a bush, and the glider exited the road; the nosewheel broke off when it impacted a ditch. The flight manual indicated that all basic nonaerobatic maneuvers are permitted within the operational speed range, which included steep turns with a maximum bank of 60°. The recommended fuel, per the flight manual, was an unleaded super grade. A warning directed that use of fuel with alcohol content and/or other additives is not permitted. Testing of recovered fuel revealed that it contained about 5% alcohol. However, examination of the fuel system revealed no evidence of preimpact malfunctions or failures that would have precluded normal operation, and the engine was operational during a postaccident engine run. Although the pilot reported the glider had 5 to 6 gallons of fuel in each of the two main tanks, a second engine test run was conducted where the engine was intentionally fuel starved. Data from the avionics and engine computers were then downloaded, plotted, and compared to data from the accident flight. Both the accident data and the fuel starvation test data similarly showed the engine began to run roughly as the rpm and fuel flow began to fluctuate. Additionally, avionics data showed that both the accident flight data and the fuel starvation test run data had similar indications. The glider's GPS tracked the accident flight from the point of takeoff to the point of the forced landing. This GPS data and the engine data were plotted to determine where the fluctuating engine rpm consistent with engine roughness and the loss of engine power occurred. The glider departed, climbed, and made multiple left turns with multiple altitude changes. The data showed the glider was in a left climbing turn when the engine began to lose power after fluctuations in engine rpm. Based on the available data, it is likely the fuel unported during the glider's climbing turn, which resulted in fuel starvation and the loss of engine power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked fuel quantity before engine roughness began.

NTSB coding

Evidence available

  • FDR / data
  • Photos
  • 15 docket documents
View NTSB final reportView NTSB docket

Docket documents15

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