Eurocopter AS-350 BA N357CH

Summary

On 23 June 2008 at about 18:45 local time, a Eurocopter AS-350 BA registered N357CH, operated by Last Frontier Air Ventures Ltd., was involved in an accident near Chickaloon, Alaska, United States. 2 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

23 June 2008 at 18:45

Classification

Accident

Location

Chickaloon, Alaska, United States

Coordinates

61.5183, -147.3169

Aircraft

Eurocopter AS-350 BA

Registration

N357CH

Category

Helicopter

Engines

1

Operator

Last Frontier Air Ventures Ltd.

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

External Load

Phase of flight

Not recorded

Route

Sutton → Chickaloon

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC08LA076

Nobody was injured.

The pilot's incorrect actions during an out-of ground-effect hover, which resulted in the helicopter entering a main rotor ring vortex state, and a settling with power condition, producing an excessive descent rate and collision with terrain.

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

Read the full NTSB narrative

Prior to the accident flight, the pilot transported several students from the National Outdoor Leadership School and their equipment to a remote glacier camp at about 8,950 feet mean sea level (msl). During that flight, the main rotor rpm dropped enough to sound the low rotor speed warning horn for a few seconds. At a staging area, in preparation for the accident flight, the pilot prepared an external load of about 400 pounds of equipment in a net to be attached to the bottom of the helicopter by a 50-foot-long line. The pilot then lifted off into an out-of-ground-effect hover (HOGE) to assess the required power, and noted that he needed about 70 percent power to maintain a hover. He then flew to the top of the glacier with the external cargo net; upon arrival at the upper camp, he established a 75-foot hover while pulling maximum power. He then reduced power to lower the cargo net to the snow. The pilot said that he reduced power too much and that the helicopter began to descend rapidly. He said that he felt a small vibration, reminiscent of entering the vortex ring produced by the main rotors. The vibration then smoothed out, but the helicopter was descending quickly. The pilot applied power but did not release the external load. The helicopter collided with snow and rolled onto its right side. The helicopter's gross weight at the time of the accident, including the external load, fuel, and the weight of the pilot and passenger, was about 4,286 pounds. At that weight, the helicopter should have been capable of an HOGE of about 9,500 feet msl.

Quoted verbatim from the NTSB record.