Aviation Accident Summaries

Aviation Accident Summary ANC08LA032

Aniak, AK, USA

Aircraft #1

N1701U

Cessna 207

Analysis

The commercial certificated pilot was returning from a remote village after a round robin flight of about 130 miles over a frozen and snow-covered river. He was in cruise flight about 500 feet agl, but then circled while holding between 6 or 7 miles east of his destination airport, awaiting a special VFR (SVFR) clearance. The weather condition in that area was about 1 mile visibility, with a ceiling of about 1,000 feet agl. After receiving his SVFR clearance, the pilot flew toward the airport, but the engine fuel pressure began fluctuating. The engine rpm began decreasing, along with the airplane's altitude. The pilot switched fuel tanks, selected full flaps, and prepared for a forced landing. He said the weather was near white-out conditions, but he could see the bank of the river. After switching fuel tanks from the left to the right tank, the engine power suddenly returned to full power. He applied forward flight control pressure to prevent the airplane from climbing too fast, but the airplane collided with the surface of the river. The airplane sustained structural damage to the wings and fuselage. At the time of the accident, the ceiling at the airport was 600 feet obscured, with a visibility of 1/2 mile in snow. Neither the fuel status of the accident airplane, nor the mechanical condition of the engine, were verified by either the NTSB or FAA.

Factual Information

On January 16, 2008, about 1215 Alaska Standard time, a Cessna 207 airplane, N1701U, sustained substantial damage when it collided with a snow and ice covered river following a partial loss of engine power, about 1 mile east of Aniak, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country positioning flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by Inland Aviation Services Inc., Aniak. The commercial certificated pilot, the sole occupant, received serious injuries. Instrument meteorological conditions prevailed in the area of the accident. VFR company flight following procedures were in effect. The flight originated at the Crooked Creek Airport, Crooked Creek, Alaska, about 1130. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on January 16, the director of maintenance for the operator reported that the pilot received a special VFR (SVFR) clearance into the Aniak Class E airspace about 1153, and was following the Kuskokwim River from Crooked Creek to Aniak. About 1225, the pilot made radio contact with another airplane, and reported that he had crashed. At the time of the accident, the surface of the Kuskokwim River was frozen and covered by snow. In a telephone conversation with the NTSB IIC, on January 17, the pilot reported that he initially departed Aniak with full fuel tanks for Crooked Creek, which is about 65 miles from Aniak, along the Kuskokwim river. During the entire flight to and from Crooked Creek, the airplane had been flown between 45 to 60 minutes with the fuel selector on the left tank. The pilot said he was in cruise flight about 500 feet agl, but then circled while holding, about 6 or 7 miles east of Aniak, awaiting a special VFR (SVFR) clearance. The weather condition in that area was about 1 mile visibility, with a ceiling of about 1,000 feet agl. After receiving his SVFR clearance, the pilot proceeded toward Aniak, but the engine fuel pressure began fluctuating, about 3 miles from Aniak. The engine rpm began decreasing, along with his altitude. He switched the fuel selector from the left tank to the right, selected full flaps, and prepared for a forced landing. He said the weather was near white-out conditions, but he could see the bank of the river. After switching fuel tanks, the engine power suddenly returned to full power. He applied forward flight control pressure to prevent the airplane from climbing too fast, but the airplane collided with the surface of the river. The airplane sustained structural damage to the wings and fuselage. The total distance along the Kusokwim River from Aniak, to Crooked Creek and back, was about 130 miles. At 1156, an automated weather report at Aniak was reporting, in part: Wind, 200 degrees (true) at 6 knots; visibility, 1 statute mile; clouds and sky condition, 600 feet broken, 1,800 feet broken, 12,000 feet overcast; temperature, 32 degrees F; dew point, 30 degrees F; altimeter, 29.77 inHg. At 1216, the weather at Aniak was reported as: Wind, 190 degrees (true) at 5 knots; visibility, 1/2 statute mile; clouds and sky condition, 600 feet overcast; temperature, 32 degrees F; dew point, 30 degrees F; altimeter, 29.79 inHg. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the director of maintenance for the operator, the ceiling was reported as 600 feet obscured, and the visibility was restricted by snow. No narrative description of the accident events was included in the accident report form. The fuel status of the airplane at the time of the accident, nor the mechanical condition of the engine, was verified by an NTSB investigator, or a Federal Aviation Administration (FAA) inspector.

Probable Cause and Findings

A partial loss of engine power for an undetermined reason. Contributing to the accident were the pilot's inadvertent encounter with IMC conditions, and a whiteout during his attempted go-around from an emergency landing approach.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports