Aviation Accident Summaries

Aviation Accident Summary ANC10LA021

Nanwalek, AK, USA

Aircraft #1

N734JM

CESSNA U206G

Analysis

Prior to touchdown on the snow and ice covered gravel runway with 850 feet of usable length, the pilot reported that the airplane floated a little, but the touchdown point and touchdown were normal. When he applied the brakes, he indicated that there was very little to no braking action. The airplane slid towards the right while in a left yaw, which he was able to correct when the braking action improved. The airplane continued to the end of the runway and impacted a snowbank. The pilot reported there were no preimpact mechanical problems with the airplane. He noted that he walked the runway after the accident, and determined that the braking action would have been slightly better had he landed in the opposite direction. The US Department of Transportation’s Alaska Airport Supplement indicates that the runway should be visually checked for condition before use.

Factual Information

On March 5, 2010, about 1630 Alaska standard time, a Cessna U206G, N734JM, registered to and operated by Smokey Bay Air, Inc.,Homer, Alaska, collided with a snowbank during the landing roll at Nanwalek Airport, Nanwalek, Alaska. Visual meteorological conditions prevailed, and a company visual flight rules (VFR) flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 135, scheduled domestic passenger flight from the Homer Airport, Homer. The airplane sustained substantial damage to the left wing. The airline transport certificated pilot and the sole passenger were not injured. The flight originated from Homer about 1600. The pilot stated that the approach to runway 01 was normal, but the airplane floated a little before touchdown on the snow and ice covered gravel runway. The touchdown and touchdown point were normal, and during the landing roll he retracted the flaps and applied the brakes but later reported the braking action as “…very little to no braking action.” The airplane slid towards the right while in a left yaw, and he regained some braking action, correcting the left yaw. The airplane continued to the end of the runway and impacted a snowbank with the right main landing gear, causing the airplane to yaw to the right. The left main landing gear then contacted the snowbank, causing the left wing to drop and strike a snowbank. The pilot reported there was no preimpact mechanical failure or malfunction of the airplane or of its systems. He later walked the runway, and determined that the braking action would have been slightly better had he landed the other direction. The pilot, age 29, holds commercial, airline transport, and flight instructor pilot certificates. At the commercial level, he has airplane single engine land and sea ratings. His last first class medical certificate with no medical restrictions was issued October 29, 2009. The submitted NTSB Pilot/Operator Aircraft Accident/Incident Report indicated the pilots’ total time in all aircraft was 5,000 hours, and he listed having 1,500 hours in the accident make and model airplane. According to the operator's Director of Maintenance, six stringers in the left wing and the outer rib were damaged, requiring removal and replacement. The Nanwalek Airport is equipped with one runway designated 01/19. The US Department of Transportation's Alaska Airport Supplement indicates the gravel runway is 1,850 feet long and 50 feet wide, with the north 1,000 feet closed indefinitely. The supplement also notes that the approach to runway 01 is restricted by an abrupt mountain face located .21 nautical mile from the approach end, and the runway is not routinely maintained. The supplement states that the runway should be visually inspected for condition before use. A surface observation weather report taken at Seldovia Airport at 1619, or approximately 11 minutes before the accident, indicates the wind was calm and the visibility was 6 statute miles with light rain and mist. A ceiling of broken clouds existed at 2,500 feet and overcast clouds existed at 3,100 feet. The temperature and dew point were both reported as 01 degrees Celsius. The altimeter setting was 28.69 inches of Mercury. The Seldovia Airport is located approximately 9 nautical miles and 028 degrees magnetic from the accident airport.

Probable Cause and Findings

The pilot's decision to land on a short, icy runway with poor braking action, resulting in a runway overrun/excursion and collision with a snowbank.

 

Source: NTSB Aviation Accident Database

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