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ERA17CA129

2017-03-12 · Mount Airy, North Carolina, United States · Minor · 1 aircraft · Status: Completed

Airport MWK

Aircraft involved

Probable cause & findings

The pilot’s improper adjustment of the prerotator motor, which resulted in its failure to disengage and the subsequent loss of aircraft control during takeoff.

Factual narrative

The pilot, who was also the owner of the of amateur-built gyroplane stated he adjusted the prerotator motor pressure plate prior to the flight by moving it closer to the clutch to improve rpm. During takeoff, the gyroplane rolled right and he was unable to maintain control. The gyroplane subsequently impacted the ground and cartwheeled, which resulted in substantial damage to the rotor, mast, and cabin. He further stated that due to his adjustment, it was likely that the prerotator did not disengage, resulting in increased right torque and the inability to control the gyroplane during takeoff. The pilot, who was also the owner of the of amateur-built gyroplane, stated that he adjusted the prerotator motor pressure plate before the flight by moving it closer to the clutch to improve rpm. During takeoff, the gyroplane rolled right, and he was unable to maintain control. The gyroplane subsequently impacted the ground and cartwheeled, which resulted in substantial damage to the rotor, mast, and cabin. The pilot further stated that, due to his adjustment, it was likely that the prerotator did not disengage, which resulted in increased right torque and the inability to control the gyroplane during takeoff. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

FAA avdata. C = Cause, F = Factor.

  • C Personnel issues-Task performance-Maintenance-Modification/alteration-Pilot - C
  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Yaw control-Attain/maintain not possible - C
  • C Aircraft-Aircraft power plant-Engine (reciprocating)-(general)-Incorrect service/maintenance - C

Verbatim from NTSB's published report. Source file NTSB_2017_ERA17CA129.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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