ASN Wikibase Occurrence # 296029
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| Date: | Monday 7 April 2003 |
| Time: | 10:15 LT |
| Type: |  Aerospatiale SA 319B Alouette III |
| Owner/operator: | Performance Helicopters LLC. |
| Registration: | N119PH |
| MSN: | 2119 |
| Year of manufacture: | 1974 |
| Total airframe hrs: | 4611 hours |
| Engine model: | Turbomeca ASTAZOU XIV |
| Fatalities: | Fatalities: 0 / Occupants: 6 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | VALDEZ, Alaska -
 United States of America
|
| Phase: | Unknown |
| Nature: | Unknown |
| Departure airport: | VALDEZQ, AK |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The commercial certificated pilot was landing a wheel/ski-equipped helicopter at a remote spot on a snow-covered ridgeline, about 4,200 feet msl. The pilot said that as the landing gear wheels touched the ridgeline, the helicopter started to shake in ground resonance. He decided to lift off, and the vibration became severe. The pilot said he lowered the collective pitch control and began a descent toward lower terrain. During the descent, the pilot said the helicopter nearly became uncontrollable until he heard one of the main rotor spacing cables snap. The previous 3 per revolution vibrations smoothed out, and became a 1 per revolution vibration. The pilot landed the helicopter on a glacier moraine. After landing, the pilot discovered that the broken spacing cable damaged the inboard trailing edge of one main rotor blade. The tail boom assembly was buckled and torn at the bottom attach point to the fuselage. A postaccident examination of the helicopter revealed that an attaching bolt, used to secure the yellow blade spacing cable to the red blade rotor grip fitting, was missing and the yellow blade damper was compressed. The missing bolt from the spacing cable fitting has a hollow shaft design which enables the bolt to shear when excessively loaded. Under extreme unbalanced conditions, the separation of the spacing cable permits an unbalanced rotor blade additional horizontal movement. Following the accident, the main rotor dampers were sent to an overhaul facility by the operator's insurance company. The overhaul facility reported that examination of the dampers did not reveal any observed malfunction.
Probable Cause: The pilot's encounter with a ground resonance condition during the landing touchdown, which resulted in the shearing of a main rotor spacing cable bolt, and buckling of the tail boom.
Accident investigation:
 |
|
Sources:
NTSB ANC03LA042
History of this aircraft
Other occurrences involving this aircraft
| 23 September 2006 | N119PH | Last Frontier Air Ventures Ltd. | 0 | Port Alsworth, Alaska | |
sub |
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 13-Oct-2022 15:43 | ASN Update Bot | Added |
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