Agusta A109A II N1WC

Summary

On 11 September 1995 at about 12:30 local time, a Agusta A109A II registered N1WC, operated by Hospital Air Transport, was involved in an accident near Winslow, Washington, United States. 3 people were on board and 3 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 September 1995 at 12:30

Classification

Accident

Location

Winslow, Washington, United States

Coordinates

47.6394, -122.5309

Aircraft

Agusta A109A II

Registration

N1WC

Category

Helicopter

Engines

2

Operator

Hospital Air Transport

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Seattle → Unknown

Aircraft damage

Destroyed

Weather

Unk

Light

Night/Dark

NTSB number

SEA95FA214

3 people died.

the pilot failed to maintain sufficient altitude/clearance above the surface of water, while flying over calm water conditions at night. Factors relating to the accident were: darkness, low ceiling, fog, glassy (calm) water conditions, and the lack of visual cues for visual perception of altitude.

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

Read the full NTSB narrative

The helicopter pilot took off at night on a positioning flight for an emergency medical service (EMS) operation. There were reports of a low overcast layer varying from 1,000 feet above ground level to the surface. The majority of the witnesses reported that the helicopter was flying low as it traveled over the ground and continued over water toward a nearby island. Subsequently, the helicopter collided with the water and sank. Several of the witnesses reported that the engine sounded normal until the helicopter crashed. Some witnesses reported a 'popping' sound or a 'laboring' sound from the engines; however, after the engines were recovered at a later date, no evidence of a preimpact mechanical failure or malfunction was found. Local residents reported that the water condition at the time of the accident was 'calm' or 'glassy.' Several small pieces of the fuselage and main rotor blades were found floating on the surface of the water. Examination revealed that 3 of the main rotor blades had separated approximately three feet out from the attach points. The fourth blade separated approximately seven feet out from the attach point; however, the blade was bent and cracked chordwise approximately three feet out from the attach point. Using side scan sonar, wreckage was found over a distance of approximately 600 feet. The landing gear was found in the extended position, and the engine power levers were found in the flight position. Also, torsional evidence was found on the tail rotor driveshaft.

Quoted verbatim from the NTSB record.