ASN Wikibase Occurrence # 361153
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| Date: | Monday 18 October 1993 |
| Time: | 15:30 LT |
| Type: |  Aérospatiale SA 315 Lama |
| Owner/operator: | Pacific Western Helicopters |
| Registration: | N49511 |
| MSN: | 2485 |
| Total airframe hrs: | 17081 hours |
| Engine model: | TURBOMECA ART III B |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Beckwourth, CA -
 United States of America
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Unknown |
| Departure airport: | Nervino, CA (O02) |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
THE PILOT WAS CONDUCTING AN EXTERNAL HELICOPTER EXTERNAL LOAD LOGGING OPERATION. AFTER RAISING TWO LOGS, THE PILOT HEARD A LOUD 'THUNK' NOISE FOLLOWED BY AN UNCONTROLLED TURN TO THE RIGHT. THE PILOT WAS UNABLE TO MAINTAIN ADEQUATE ROTOR RPM BECAUSE HE COULD NOT LOWER THE COLLECTIVE. EXAMINATION OF THE COLLECTIVE SERVO REVEALED IT TO HAVE INTERNAL LEAKAGE WHICH CAUSED A HYDRAULIC LOCK IN THE SERVO. THE SERVO EXTENSION AND RETRACTION TIME EXCEEDED THE MANUFACTURER'S SPECIFICATIONS.
Probable Cause: was the worn collective servo causing a hydraulic lock and not allowing the pilot to lower the collective. This condition caused the main rotor blades rpm to decay.
Accident investigation:
 |
|
Sources:
NTSB LAX94LA017
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 16-Mar-2024 15:19 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
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