N7482F Hughes 269C accident

NTSB CEN17LA229 · 2017-06-10 · Tallulah, LA · near TVR

Summary

The commercial pilot reported that the helicopter's engine start and run-up were normal. At full power for takeoff, the helicopter began to vibrate. The pilot "rolled the throttle off" and lowered the collective; however, the vibrations became worse and the helicopter "began to destroy itself." He reported that he had not re-centered before the cyclic trim before takeoff as noted on the checklist, and it remained at a nearly full-forward position from the previous flight. He noted that if the cyclic had been centered, the vibrations would have stopped. However, with the trim full forward, the rotor blades began hitting the stops, causing the vibrations. The pilot added that there were no malfunctions or failures with the helicopter before the accident.

Full narrative

On June 10, 2017, about 1320 central daylight time, a Hughes 269C helicopter, N7482F, was substantially damaged during a ground resonance event at the Vicksburg Tallulah Regional Airport (TVR), Tallulah, Louisiana. The pilot was not injured. The helicopter was registered to Wade and Son, Inc., and operated by the pilot as a 14 Code of Federal Regulations Part 91 instructional flight. Day visual meteorological conditions prevailed at the accident site. The flight was not operated on a flight plan. The local flight was originating at the time of the accident.The pilot reported that the cyclic trim was not re-centered before takeoff as noted on the checklist. Instead, it remained at a nearly full forward position from the previous flight. The engine start and run-up were normal. At full power for takeoff, the helicopter began to vibrate. The pilot "rolled the throttle off" and lowered the collective; however, the vibrations became worse and the helicopter "began to destroy itself." He noted that if the cyclic had been centered, the vibrations would have stopped. However, with the trim full forward, the rotor blades began hitting the stops causing the vibrations. The pilot added that there were no malfunctions or failures with the helicopter before the accident.

The helicopter came to rest upright on the airport ramp. A postaccident examination revealed that the engine had partially separated from the airframe and the main rotor gearbox had separated from the rear bulkhead. The landing skid dampers appeared intact, with no visible damage or fluid leakage.

Probable cause

The pilot's failure to reset the cyclic trim before takeoff, which resulted in ground resonance. The National Transportation Safety Board determined the probable cause of this accident.

Circumstances

Event type: Accident
Highest injury: None
Weather conditions: Visual Meteorological Cond
Light condition: Day
Sky condition: NONE
Ceiling (ft): 0
Visibility (sm): 10
Wind direction: 0
Wind speed (kt): 5
Temperature (F): 84
Nearest airport: Vicksburg Tallulah Regional
Distance from field: 0.0
Airport elevation: 86

Aircraft

Registration	Make	Model	Damage	FAR part
N7482F	HUGHES	269C	SUBS	091

Sequence of events

#	Occurrence	Phase
1	Takeoff Ground resonance defining	Takeoff

Findings

Finding
Personnel issues-Task performance-Use of equip/info-Use of checklist-Pilot	cause
Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot	cause