Pilot Debrief

SOPWITH Type 9400 near Van Alstyne, TX — 2020-07-03

Final reportCEN20LA259
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Date
2020-07-03
Location
Van Alstyne, TX, USA
Airport
66XS
Aircraft
SOPWITH Type 9400
Registration
N5539
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Maneuvering

Probable cause

An inflight loss of aileron control due to movement of a control connector.

NTSB narrative

During a test flight the pilot moved the control stick fully to the right to roll out of a turn, but the airplane did not respond, and the pilot suspected a failure in the aileron controls. The airplane eventually rolled wings level and the pilot elected to perform an emergency landing to a corn field, during which the airplane hit a tree and descended into the field. The wings and fuselage were substantially damaged during impact. The pilot, who was also the builder of the airplane, examined the wreckage and determined that a rocking tube that connected the front cockpit control stick to the rear control stick had moved rearward about 1 inch. The aileron cables connected to a horn affixed to this tube. The rearward movement of the rocking tube was sufficient for the front part of the tube to come loose from its socket, which likely affected the control authority of the ailerons and resulted in the pilot’s inability to control the airplane. The pilot explained that there was nothing in the original design that prevented the rocking tube from sliding aft.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have inspected control systems before the flight to prevent failure.

NTSB coding

Evidence available

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

Docket documents5

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