Aviation Accident Summaries

Aviation Accident Summary ANC09LA018

Atmautluak, AK, USA

Aircraft #1

N5246D

CESSNA 172N

Analysis

The commercial pilot was on an on-demand air taxi flight with three passengers and their baggage. He stated that he was approaching a remote airport to land on Runway 15 when the wind shifted and he encountered wind gusts that made the airplane difficult to control. He said that he added full power to go around, but that the airplane would not climb, stalled, and then descended to the ground short of the runway. The airplane sustained substantial damage to the wings and fuselage. Federal Aviation Administration inspectors found no mechanical problems with the airplane and determined that it was being operated at least 166 pounds over the maximum gross weight limit. Operating an airplane over the certificated gross weight is prohibited and markedly reduces its performance capabilities.

Factual Information

On February 7, 2009, about 0945 Alaska standard time, a Cessna 172N airplane, N5246D, operated by JP Air, Bethel, Alaska, as an on demand, Title 14, CFR Part 135 air taxi flight, crashed during a go-around while on approach to the Atmautluak airport, Atmautluak, Alaska. The commercial pilot and the three passengers reported minor injuries. The flight departed Bethel about 0925, and was en route to Atmautluak, with a return to Bethel. Visual meteorological conditions prevailed, and a company flight plan was in effect. During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge on February 7 at 1515, the pilot reported that he encountered shifting winds during his approach to land on runway 15, and attempted to go-around to land on runway 33. During the attempted go-around, the airplane did not climb as expected, and the pilot said an aerodynamic stall ensued, resulting in a collision with tundra short of the runway. He was asked about the number of passengers and fuel aboard, and said he had full tanks when he departed Bethel, with three passengers and their baggage. In a written report to the NTSB signed by the pilot and director of operations, the fuel quantity at the time of departure from Bethel is listed as 20 gallons and the airplane's gross weight at the time of the accident as 2287 pounds, below the 2300 pounds licensed maximum gross weight. Two Federal Aviation Administration (FAA) aviation safety inspectors traveled to the accident site and to Bethel on February 9 and 10 to inspect the airplane and its records, interview the pilot, and to talk to the witnesses and passengers. In the process, the inspectors discovered that the airplane's licensed empty weight was 1514.6 pounds. Total passenger weights, not accounting for their clothing, was 552 pounds, with an additional 50 pounds of baggage. The pilot's FAA medical weight is listed as 249 pounds, although the FAA inspector who interviewed him is 300 pounds, and thought the pilot was larger than him. Assuming 15 gallons of usable fuel at 6.7 pounds per gallon, the total weight of the airplane at the time of the accident was at least 2466.1 pounds, or 166.1 pounds over the allowable gross weight. Additional fuel, passenger clothing, or pilot's weight in excess of the amount stated, would increase the amount over the maximum allowable gross weight. Copies of the FAA inspector's statements are included in the public docket of this report. In their statements, they note that they pilot indicated he thought the airplane may have been over the allowable gross weight at the time of the accident. The inspectors discovered no evidence of any preimpact mechanical problems with the airplane. In the operator's report to the NTSB, signed by the pilot and director of operations, the block for indicating mechanical malfunction was checked "NO."

Probable Cause and Findings

The pilot's failure to maintain adequate airspeed while landing in gusty winds, which resulted in an aerodynamic stall; his improper aircraft weight calculations; and his operation of the airplane over the allowable gross weight limit.

 

Source: NTSB Aviation Accident Database

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