Pilot Debrief

CHAPMAN T-BIRD II near Potosi, MO — 2017-07-31

Final reportCEN17LA293
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Date
2017-07-31
Location
Potosi, MO, USA
Airport
8WC
Aircraft
CHAPMAN T-BIRD II
Registration
N204BC
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

The pilot's loss of airplane control during a departure turn for reasons that could not be determined.

NTSB narrative

The private pilot, who had not flown this experimental, amateur-built airplane before the accident flight, had just departed for a local flight. Witnesses reported that the airplane made a right turn, the wing and nose then dropped, and the airplane disappeared out of view before impacting terrain. One of the witnesses stated that the airplane was having "difficulties" after it took off. Another witness, who identified himself as part owner of the airplane, stated that before departure, he noted that the pilot's leg interfered with the control yoke due to the pilot's size and the small cockpit. He also stated that the airplane tended to "drop a wing" in turns, which required a quick recovery, and that the airplane was a little "squirrelly" because it reacted quickly to control inputs. Several modifications from the original configuration had been made to the airplane, which included changing the landing gear from a conventional to tricycle gear; installing different brakes; installing a differently shaped fuel tank; changing and raising the seats; modifying the steering assembly; and, most recently, changing the flaperons to a flap and aileron design. The part owner stated that they did not conduct any flight tests or aerodynamic performance calculations after the modifications. It could not be determined what effect, if any, the modifications had on this accident. It is possible that the pilot lost control of the airplane during the departure turn due to the airplane's unique handling characteristics as the part owner described, the pilot's unfamiliarity with the modified airplane, or the pilot's leg interfering with the movement of the control yoke. The exact reason for the loss of control could not be determined.

Analysis

Primary failure mode
Human factors
First missed decision gate
Conducting flight tests after major modifications to ensure safety and compliance.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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