ASN Wikibase Occurrence # 364644
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| Date: | Saturday 24 August 1991 |
| Time: | 19:50 LT |
| Type: |  Hiller UH-12D |
| Owner/operator: | Pathfinder Technology Inc. |
| Registration: | N100HH |
| MSN: | 1266 |
| Total airframe hrs: | 5868 hours |
| Engine model: | LYCOMING VO-435-AIC |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Sparks, NV -
 United States of America
|
| Phase: | En route |
| Nature: | Private |
| Departure airport: | Reno, NV (NONE) |
| Stead, NV (45D) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
THE CERTIFICATED PRIVATE HELICOPTER PILOT, THE SOLE OCCUPANT, WAS ON A LOCAL AREA FLIGHT WHEN A STRONG, MEDIUM TO HIGH FREQUENCY VIBRATION DEVELOPED IN THE TAIL SECTION OF HIS HELICOPTER. THE PILOT ELECTED TO MAKE A PRECAUTIONARY LANDING IN AN OPEN DIRT AREA, AND EXECUTED AN AUTOROTATION. AFTER TOUCHDOWN THE HELICOPTER SLID ON ROUGH, ROCKY TERRAIN, CAUSING THE MAIN ROTOR BLADES TO CONTACT THE TAIL BOOM. THREE FEET OF THE TAIL BOOM INCLUDING THE TAIL ROTOR GEAR BOX AND BLADES, AND THE TAIL ROTOR DRIVE SHAFT WERE SEVERED. AN EXAMINATION OF THE TAIL ROTOR DRIVE SHAFT AT THE POSITION WHERE A SUPPORT BEARING IS MOUNTED, REVEALED SIGNS OF HEAT AND WEAR. DURING THE IMPACT SEQUENCE, THE DRIVE SHAFT SUPPORT BEARING DEPARTED THE HELICOPTER AND WAS NOT RECOVERED.
Probable Cause: THE ENCOUNTER WITH ROUGH, UNSUITABLE TERRAIN DURING A PRECAUTIONARY LANDING. CONTRIBUTING TO THE ACCIDENT WAS THE PILOT'S DECISION TO MAKE AN AUTOROTATION AFTER ENCOUNTERING AN AIRFRAME VIBRATION.
Accident investigation:
 |
|
Sources:
NTSB LAX91LA369
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 19-Mar-2024 17:17 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
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