ASN Wikibase Occurrence # 295445
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| Date: | Tuesday 29 July 2003 |
| Time: | 15:30 LT |
| Type: |  Hughes 269C-1 |
| Owner/operator: | Hillsboro Aviation Inc. |
| Registration: | N61442 |
| MSN: | 0002 |
| Year of manufacture: | 1992 |
| Total airframe hrs: | 3724 hours |
| Engine model: | Lycoming HO-360 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Scappoose, Oregon -
 United States of America
|
| Phase: | Unknown |
| Nature: | Private |
| Departure airport: | San Luis Obispo-County Airport, CA (SBP/KSBP) |
| Portland-Hillsboro Airport, OR (HIO/KHIO) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot initiated the flight at maximum gross weight. After picking the helicopter up to a hover and stabilizing RPM, the RPM began to dip. Unable to recover RPM, the helicopter settled to the ground and subsequently encountered a ground resonance condition. After closing the throttle and lowering the collective, the helicopter began to shudder and turned 45 degrees to the left before the ground resonance condition subsided. The pilot was successful in his attempt to pick the helicopter up again to a hover, stabilizing engine RPM, coming to a stable hover, and sustaining rotor RPM during a left pedal turn. While attempting forward flight from this position the helicopter's RPM dipped again, resulting in the pilot having to set the helicopter down again. The aircraft entered ground resonance a second time, this time worse than the first, resulting in the helicopter being shook apart around the pilot and his passenger. Post-accident tests indicated that all four landing gear dampers, having failed a load stroke test, were set too hard, resulting in a ground resonance condition being encountered after a landing due to reduced rotor RPM.
Probable Cause: The helicopter encountering a ground resonance condition following a failure to maintain hovering flight. Contributing factors to the accident included the pilot's failure to maintain rotor RPM and the high pressure state of the landing gear shock absorbing dampers.
Accident investigation:
 |
|
Sources:
NTSB SEA03LA160
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 13-Oct-2022 08:38 | ASN Update Bot | Added |
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