Aviation Accident Summaries

Aviation Accident Summary ANC00TA039

MANOKOTAK, AK, USA

Aircraft #1

N5006R

Bell 206B

Analysis

The airline transport certificated helicopter pilot was transporting a radio technician from a remote radio repeater site as part of a government contract with the U.S. Coast Guard. After departing the repeater site, the pilot was in cruise flight about 500 feet above the ground. The weather conditions were 700 feet overcast, with a visibility of 1 to 2 miles. Snow squalls were moving through the area. The pilot said he was maintaining his visual reference to the ground by using terrain features while flying over a flat, snow-covered delta. Just before the accident, the pilot said he was utilizing a line of shrubs as a point of visual reference, but he could not see any additional visual cues beyond the line of shrubs. He decided to turn around and began a right turn. During the turn, he said he lost all visual references to the ground. He looked at the helicopter's attitude indicator, and noticed he was in a 45 degree right bank, and a 10 degree nose low attitude. He leveled the helicopter and applied collective pitch to begin a climb. The helicopter then collided with the snow. During the collision, the landing gear skids were torn off the fuselage, the main rotor blades separated from the rotor mast, and the tail boom was severed. The helicopter came to rest on its right side. The helicopter was not equipped with a radar altimeter.

Factual Information

On March 29, 2000, about 2000 Alaska standard time, a skid equipped Bell 206B helicopter, N5006R, sustained substantial damage after colliding with snow-covered terrain, about 10 miles south-southwest of Manokotak, Alaska, about latitude 58 degrees, 51 minutes north, and longitude 159 degrees, 14 minutes west. The helicopter was being operated as a visual flight rules (VFR) government operated flight, when the accident occurred. The helicopter was transporting a technician from a remote radio repeater site as part of a contract with the U.S. Coast Guard, Alameda, California. The contract holder, Engineered Systems Inc., Omaha, Nebraska, was utilizing Calalaska Helicopters Inc., Santa Maria, California, to service the repeater site. The airline transport certificated pilot, and the sole passenger, were not injured. Instrument meteorological conditions prevailed at the accident site. A VFR flight plan was filed by radio at 1948. The flight originated from the repeater site in the Tuklung Mountains, about 1950. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 30, 2000, the pilot, who is also the Director of Operations for Calalaska Helicopters, reported that after departing the repeater site, he was in cruise flight about 500 feet above the ground. He was proceeding toward Dillingham, Alaska. The weather conditions were 700 feet overcast, with a visibility of 1 to 2 miles. Snow squalls were moving through the area. The pilot said he was maintaining his visual reference to the ground by using terrain features while flying over a flat, snow-covered delta. Just before the accident, the pilot said he was utilizing a line of shrubs as a point of visual reference, but he could not see any additional visual cues beyond the line of shrubs. He decided to turn around and proceed to the coast of the Nushagak Peninsula, and then to Dillingham. He began a right turn, and during the turn, he said he lost all visual references to the ground. He looked at the helicopter's attitude indicator, and noticed he was in a 45 degree right bank, and a 10 degree nose low attitude. He leveled the helicopter and applied collective pitch to begin a climb. The helicopter then collided with the snow. During the collision, the landing gear skids were torn off the fuselage, the main rotor blades separated from the rotor mast, and the tail boom was severed. The helicopter came to rest on its right side. The helicopter was not equipped with a radar altimeter. The closest official weather observation station is Dillingham, which is located about 26 nautical miles northeast of the accident site. At 1955, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, 300 degrees (true) at 8 knots; visibility, 5 statute miles in light snow and mist; clouds and sky condition, 2,200 feet broken, 2,700 feet overcast; temperature, 33 degrees F; dew point, 27 degrees F; altimeter, 29.12 inHg.

Probable Cause and Findings

The pilot's continued VFR flight into instrument meteorological conditions. Factors in the accident were low ceilings and snow, and snow-covered terrain.

 

Source: NTSB Aviation Accident Database

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