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20170610009439A

Accident · Substantial damage
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FAA accident report · Hughes 269C · Tallulah, LA · June 10, 2017

FAA Aviation Safety Information Portal

© OpenStreetMap
Date
June 10, 2017 · 13:20 local
Place
Tallulah, LA
Airport
Vicksburg Tallulah Regional
Phase of flight
Run-Up Area
Operating rules
General operating rules (Part 91)
Damage
Substantial damage
Aircraft
N7482F
NTSB investigation
NTSBCEN17LA229
Reported as
Hughes 269C
People aboard
1
Fatal injuries
0
Other injuries
0
Pilot’s certificates
Commercial pilot, flight instructor
Pilot’s flight hours
12,122 total40 in this make and model40 in the last 90 days
N7482FRegistered now · Hughes 269CS/N 170576Airframe modelHughes 269C

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

When interviewed, the privacy data omittedpilot explained that he had flown in to talullah and shut down the helicopter to attend a gathering for a few hours. After landing the pilot stated that the main rotor trim had never been re-set from forward flight cruise settings. Prior to departure the pilot conducted a successful pre takeoff magneto run-up. He then ran the engine back up to achieve main engine rotor speed for takeoff when the helicopter began to violently shake likely due to ground resonance. At that point the pilot stated that he lowered the collective and closed the engine throttle at the same time. The pilot also stated that the accident was his fault do to his failure to reset the trim and check for center control stick setting prior to conducting a pre-takeoff a engine run-up. The extreme forward trim settings likely caused the main rotor blades to contact the bump stops during the engine run resulting in the induced vibration that led to the ground resonance event. The violent shaking caused the main transmission/rotor shaft to tear away from the aircraft, and the entire fuselage to be canted slightly left side up when resting on the skids. The engine also broke loose from its mounts. The event was classified as an accident due to significant airframe/rotor/engine damage. Due to Sikorsky service bulletin asb C1B-041 stating that improperly serviced landing gear skid dampeners can be a contributing factor in a ground resonance event, they were visually inspected and found to be serviceable with only 34.9 hours total time in service since overhaul when installed on this airframe according to the aircraft maintenance logbook.

As the FAA filed it

WHEN INTERVIEWED, THE ^PRIVACY DATA OMITTED^PILOT EXPLAINED THAT HE HAD FLOWN IN TO TALULLAH AND SHUT DOWN THE HELICOPTER TO ATTEND A GATHERING FOR A FEW HOURS. AFTER LANDING THE PILOT STATED THAT THE MAIN ROTOR TRIM HAD NEVER BEEN RE-SET FROM FORWARD FLIGHT CRUISE SETTINGS. PRIOR TO DEPARTURE THE PILOT CONDUCTED A SUCCESSFUL PRE TAKEOFF MAGNETO RUN-UP. HE THEN RAN THE ENGINE BACK UP TO ACHIEVE MAIN ENGINE ROTOR SPEED FOR TAKEOFF WHEN THE HELICOPTER BEGAN TO VIOLENTLY SHAKE LIKELY DUE TO GROUND RESONANCE. AT THAT POINT THE PILOT STATED THAT HE LOWERED THE COLLECTIVE AND CLOSED THE ENGINE THROTTLE AT THE SAME TIME. THE PILOT ALSO STATED THAT THE ACCIDENT WAS HIS FAULT DO TO HIS FAILURE TO RESET THE TRIM AND CHECK FOR CENTER CONTROL STICK SETTING PRIOR TO CONDUCTING A PRE-TAKEOFF A ENGINE RUN-UP. THE EXTREME FORWARD TRIM SETTINGS LIKELY CAUSED THE MAIN ROTOR BLADES TO CONTACT THE BUMP STOPS DURING THE ENGINE RUN RESULTING IN THE INDUCED VIBRATION THAT LED TO THE GROUND RESONANCE EVENT. THE VIOLENT SHAKING CAUSED THE MAIN TRANSMISSION/ROTOR SHAFT TO TEAR AWAY FROM THE AIRCRAFT, AND THE ENTIRE FUSELAGE TO BE CANTED SLIGHTLY LEFT SIDE UP WHEN RESTING ON THE SKIDS. THE ENGINE ALSO BROKE LOOSE FROM ITS MOUNTS. THE EVENT WAS CLASSIFIED AS AN ACCIDENT DUE TO SIGNIFICANT AIRFRAME/ROTOR/ENGINE DAMAGE. DUE TO SIKORSKY SERVICE BULLETIN ASB C1B-041 STATING THAT IMPROPERLY SERVICED LANDING GEAR SKID DAMPENERS CAN BE A CONTRIBUTING FACTOR IN A GROUND RESONANCE EVENT, THEY WERE VISUALLY INSPECTED AND FOUND TO BE SERVICEABLE WITH ONLY 34.9 HOURS TOTAL TIME IN SERVICE SINCE OVERHAUL WHEN INSTALLED ON THIS AIRFRAME ACCORDING TO THE AIRCRAFT MAINTENANCE LOGBOOK.

NTSB investigation

The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.

NTSB CEN17LA229Accident · No injuriesLimited investigationFinal reportTallulah, LAThe pilot's failure to reset the cyclic trim before takeoff, which resulted in ground resonance.Jun 10, 2017 · Substantial damage

Other reports on N7482F · 1

Matched to the same aircraft by N-number and date.

Accident 19800603046119ALow Level Operations · Dexter, MNUnable to recover from high sink rate descending from procedure turn. Believed settling with power, cause.Jun 3, 1980 · Substantial damage