CircumFlightN9658F Hughes 269C accident
NTSB GAA16CA363 · 2016-07-01 · Cullman, AL · near CMD
Docket — crew, injuries and powerplant
Summary
The helicopter flight instructor reported that the commercial pilot rated/helicopter flight instructor candidate receiving instruction was practicing autorotations with power recovery to the runway; during a practice 180 degree autorotation, the flight instructor candidate executed the landing flare too low to the ground resulting in a tail rotor strike. The flight instructor further reported that he took the controls and landed the helicopter after it had yawed, un-commanded to the right, about 180 degrees. The helicopter sustained substantial damage to the vertical stabilizer and tail rotor drive assembly. The flight instructor reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. The FAA Helicopter Flying Handbook FAA-H-8083-21A (2012) discusses procedures for autorotation and states in part: Care must be taken in the execution of the flare so that the cyclic control is neither moved rearward so abruptly that it causes the helicopter to climb nor moved so slowly that it does not arrest the descent, which may allow the helicopter to settle so rapidly that the tail rotor strikes the ground… extreme caution should be used to avoid an excessive nose high and tail low attitude below 10 feet. The helicopter must be close to the landing attitude to keep the tail rotor from contacting the surface.
Full narrative
The helicopter flight instructor reported that the commercial pilot rated/helicopter flight instructor candidate receiving instruction was practicing autorotations with power recovery to the runway; during a practice 180 degree autorotation, the flight instructor candidate executed the landing flare too low to the ground resulting in a tail rotor strike. The flight instructor further reported that he took the controls and landed the helicopter after it had yawed, un-commanded to the right, about 180 degrees.
The helicopter sustained substantial damage to the vertical stabilizer and tail rotor drive assembly.
The flight instructor reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
The FAA Helicopter Flying Handbook FAA-H-8083-21A (2012) discusses procedures for autorotation and states in part:
Care must be taken in the execution of the flare so that the cyclic control is neither moved rearward so abruptly that it causes the helicopter to climb nor moved so slowly that it does not arrest the descent, which may allow the helicopter to settle so rapidly that the tail rotor strikes the ground… extreme caution should be used to avoid an excessive nose high and tail low attitude below 10 feet. The helicopter must be close to the landing attitude to keep the tail rotor from contacting the surface.
Probable cause
The helicopter flight instructor candidate's improper execution of the autorotation, resulting in abnormal ground contact and subsequent damage to the vertical stabilizer and tail rotor drive assembly. 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
- Ceiling (ft)
- 0
- Visibility (sm)
- 10
- Wind direction
- 290
- Wind speed (kt)
- 8
- Temperature (F)
- 93
- Nearest airport
- CULLMAN RGNL-FOLSOM FIELD
- Distance from field
- 0.0
- Airport elevation
- 969
Aircraft
| Registration | Make | Model | Damage | FAR part |
|---|---|---|---|---|
| N9658F | HUGHES | 269C | SUBS | 091 |
Sequence of events
| # | Occurrence | Phase |
|---|---|---|
| 1 | Autorotation Attempted remediation/recovery | Descent |
| 2 | Landing-flare/touchdown Abnormal runway contact defining | Cruise |
| 3 | Autorotation Loss of control in flight | Descent |
| 4 | Autorotation Hard landing | Descent |