Pilot Debrief

WILSON BUGATTI-DEMONGE 100P near Burns Flat, OK — 2016-08-06

Final reportCEN16FA307
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Date
2016-08-06
Location
Burns Flat, OK, USA
Airport
CSM
Aircraft
WILSON BUGATTI-DEMONGE 100P
Registration
N110PX
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Initial climb

Probable cause

The pilot's failure to maintain airspeed following an engine anomaly during the initial climb after takeoff, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall. Contributing to the accident was an engine anomaly, the reason for which could not be identified during postaccident examination.

Contributing factors

Contributing to the accident was an engine anomaly, the reason for which could not be identified during postaccident examination.

NTSB narrative

The airline transport pilot departed from a 13,500 ft long runway with a right quartering headwind present on a local test flight in an experimental, amateur-built, twin-engine airplane, which was a replica of a 1930s-era air racer. During the initial climb after takeoff , the airplane entered a right bank followed by a left bank. The left bank increased, and the airplane entered a nose-low descent that continued until it impacted terrain in an inverted attitude. The airplane was equipped with several onboard cameras that captured video footage of the accident flight. The video revealed that the left/forward engine began surging after liftoff and reached its maximum operating speed (red line) twice during the short flight. Although the pilot attempted to control the forward engine rpm with the throttle lever, the throttle inputs had no apparent effect. Based on the design of the propeller drive train, it is a possibility that the forward engine clutch was slipping. The airplane's airspeed decreased below its design stall speed and the angle of attack increased; the airplane then rolled left and subsequently impacted the ground. A postaccident examination of the airplane did not reveal any preimpact flight control anomalies. Examination of the engines did not identify a reason for the surging of the forward engine or slipping of the clutch. The sequence of events as described by witness statements and the onboard video was consistent with a loss of airspeed following an engine anomaly and a subsequent aerodynamic stall. Toxicological testing revealed alcohols were present in samples taken during the autopsy. Given the putrefaction of the samples, it is likely that all detected alcohols were the result of postmortem production. Terrain from the accident site to one quarter mile north of the accident site was suitable for an emergency landing there.

Analysis

Primary failure mode
Loss of control
First missed decision gate
Pilot could have aborted takeoff during initial climb when control issues began.

NTSB coding

Evidence available

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

Docket documents10

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WILSON BUGATTI-DEMONGE 100P near Burns Flat, OK — 2016-08-06 · Pilot Debrief