Hughes 269C-1 N61442

Summary

On 29 July 2003 at about 23:30 local time, a Hughes 269C-1 registered N61442 was involved in an accident near Scappoose, Oregon, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

29 July 2003 at 23:30

Classification

Accident

Location

Scappoose, Oregon, United States

Nearest airport

Scappoose Industrial Airpark (SPB)

Coordinates

45.7706, -122.8619

Aircraft

Hughes 269C-1

Registration

N61442

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Scappoose → Hillsboro

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA03LA160

2 people had minor injuries.

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.

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

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.