Hughes 369D N1088G

Summary

On 4 January 2007 at about 21:10 local time, a Hughes 369D registered N1088G, operated by Highline Helicopters, was involved in an accident near Lyman, Washington, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

4 January 2007 at 21:10

Classification

Accident

Location

Lyman, Washington, United States

Coordinates

48.4472, -122.0536

Aircraft

Hughes 369D

Registration

N1088G

Category

Helicopter

Engines

1

Operator

Highline Helicopters

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Lyman → Lyman

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA07LA041

1 person was seriously injured.

The pilot's intentional flight into adverse weather conditions, which resulted in a loss of engine power during hover due to snow and ice ingestion. Factors associated with the accident are the pilot's delayed remedial actions, and snow and icing conditions.

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

Read the full NTSB narrative

The pilot made two long-line movements of cargo in light dry snow. After completing the second load, the pilot noticed that the snow had turned wet and heavy, and he told the ground crew that he was leaving the area. As he turned to depart the area, one of the ground crew radioed him and said that he was going to pass near one of the loads, and suggested that he pick it up. The pilot maneuvered toward the load, and entered into a hover to swing the long-line hook forward. Just as he entered the hover, the engine lost power, and the pilot delayed his emergency autorotation to allow the ground crew person to find cover. Because the rotor system energy decayed during the pilot's intentional delay of the autorotation, he was unable to control the descent, and the helicopter settled onto the terrain at an excessive rate of descent. The pilot stated that when he changed the angle of attack to put the hook in the right location, he believes a layer of wet snow and ice crystals lifted off the canopy and entered the engine particle separator, leading to a loss of engine power. A postaccident inspection did not reveal evidence of any system malfunction or anomaly.

Quoted verbatim from the NTSB record.