ASN Wikibase Occurrence # 353216
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Date: | Tuesday 8 June 1999 |
Time: | 08:15 LT |
Type: | Hughes 369D |
Owner/operator: | Olympic Air, Inc. |
Registration: | N8306F |
MSN: | 2740 |
Total airframe hrs: | 11504 hours |
Engine model: | Allison C20-B |
Fatalities: | Fatalities: 0 / Occupants: 1 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Southbend, WA -
United States of America
|
Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
Nature: | Unknown |
Departure airport: | |
Destination airport: | |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:Just after releasing his external load, the pilot applied power in order to climb away from the release area. As he applied power, a puff of smoke came from the engine, followed immediately by a complete loss of power. The helicopter then began spinning to the left and descending rapidly. The pilot attempted an autorotation in a confined area, and the aircraft impacted the ground sufficiently hard to result in substantial damage. A teardown inspection of the engine determined that a three-inch section of the compressor impeller disc had separated, leading to total failure of the engine. Metallurgical examination of the impeller revealed that the disc failed due to the propagation of fatigue cracks that initiated in corrosion pits on the aft face of the disc. According to the metallurgist, the corrosion was due to exposure to environmental elements, and not due to repetitive cyclic operation.
Probable Cause: The complete loss of power, due to a failure of the compressor impeller disk. Factors include the low altitude of the helicopter at the time of the power loss, and the need to autorotate in a confined area.
Accident investigation:
|
| |
Investigating agency: | NTSB |
Report number: | SEA99LA082 |
Status: | Investigation completed |
Duration: | 1 year and 5 months |
Download report: | Final report |
|
Sources:
NTSB SEA99LA082
Location
Revision history:
Date/time | Contributor | Updates |
09-Mar-2024 11:36 |
ASN Update Bot |
Added |
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