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April 17, 2012 · Hughes 269A Undesignat · N69HJ

Grinnell, IA

Overview

Report Status
Final with probable cause
Event Type
Accident
Date
April 17, 2012
Injury Outcomes
No injuries (2 uninjured)
Location
Grinnell, IA
Aircraft
Hughes 269A Undesignat
Tail Number
N69HJ
Injuries
None
Aircraft Damage
Substantial
NTSB Number
CEN12LA247

The helicopter began to vibrate as the pilot raised the collective for liftoff. The pilot lowered the collective and closed the throttle when the vibration began; however, he was too late in recognizing the onset of ground resonance, which resulted in a violent, uncontrollable oscillation and separation of the tail boom from the fuselage. Examination of the helicopter revealed no anomalies that would have precluded normal operation.

NTSB Probable Cause

The pilot's improper liftoff technique, which resulted in ground resonance, and the pilot's delayed recognition of the ground resonance.

Full Narrative

On April 17, 2012, about 1116 central daylight time, a Hughes 269A, N69HJ, experienced ground resonance during takeoff at Grinnell Regional Airport (GGI), Grinnell, Iowa. The pilot subsequently aborted the takeoff. The commercial pilot and a passenger were uninjured. The helicopter sustained substantial damage to the fuselage. The helicopter was registered to Lowry Flying Service Inc and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and a flight plan had not been filed for the local flight that was originating at the time of the accident. The pilot stated that when he raised the collective for liftoff, the helicopter started to vibrate. He "rolled the collective down" and "throttle off," but it was too late, and the helicopter shook apart "immediately." The transmission broke severing the tail. The rotor blades hit the ground. According to the Federal Aviation Administration inspector, the helicopter never lifted off the ground during the accident flight. The pilot experienced ground resonance on three previous flights, the first of which was during takeoff and the other two occurred during landing. During the previous three occurrences of ground resonance, the pilot was able to identify and initiate a successful recovery. During the accident flight, the pilot was too late in recognizing the onset of ground resonance. There were no mechanical anomalies that would have precluded normal operation.

Flight

Event TypeAccident
Event Time11:16 CDT
Nearest AirportGrinnell Regional Airport (0nm)
Flight Plan FiledNone
Flight Plan ActivatedNo
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftHughes 269A Undesignat
Tail NumberN69HJ
Aircraft CategoryHeli
DamageSubstantial
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · HIO-360-B1A · Reciprocating · 180
Seats2

People & Injuries

Injury SummaryNo injuries (2 uninjured)
Fatal0
Serious0
Minor0
Uninjured2
Total2
Crew 1Age 59 · Second Class · None

Conditions

ConditionsVMC
LightDaylight
Wind150° @ 4 kt
Visibility10 sm
CeilingNone
Temperature / Dew Point55 / 37 C
Altimeter30.35 inHg
Observation Time16:15
Weather SourceWFAC

Appendix: Source Data