Aerospatiale SA-319B N119PH

Summary

On 7 April 2003 at about 19:15 local time, a Aerospatiale SA-319B registered N119PH, operated by Performance Helicopters LLC., was involved in an accident near Valdez, Alaska, United States. 6 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

7 April 2003 at 19:15

Classification

Accident

Location

Valdez, Alaska, United States

Coordinates

61.1883, -145.3447

Aircraft

Aerospatiale SA-319B

Registration

N119PH

Category

Helicopter

Engines

1

Operator

Performance Helicopters LLC.

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Valdezq → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC03LA042

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.