Aviation Accident Summaries

Aviation Accident Summary ANC96LA063

DILLINGHAM, AK, USA

Aircraft #1

N9985Y

Champion 7GCB

Analysis

The airplane was equipped with oversized, 29 inch Gar Aero 'Tundra' tires. A witness reported that as the airplane was landing on a hard surfaced runway, it swerved slightly, then veered to the right. The airplane's left main landing gear wheel separated, and the left main landing gear subsequently collapsed. The axle's fracture surfaces were consistent with an overload failure. The same pilot and airplane had been involved in an earlier ground loop/landing incident on a hard surfaced runway, two days before the accident landing.

Factual Information

On May 2, 1996, about 1425 Alaska daylight time, a "Tundra" tire equipped 7GCB Champion airplane, N9985Y, operating as a business flight for the purpose of fish spotting, sustained substantial damage while landing at the Dillingham Airport, Dillingham, Alaska. The commercial certificated pilot and sole passenger aboard were not injured. The 14 CFR Part 91 flight operated in visual meteorological conditions without a flight plan. The flight originated in the vicinity of King Salmon, Alaska, time unknown. The accident was partially witnessed by FAA Anchorage Flight Standards District Office inspector Alfred Dilay. Inspector Dilay observed the airplane during a portion of the landing roll. He said he saw the left main landing gear wheel separate from the landing gear leg. The airplane then settled on the left gear leg, and the airplane turned to the right, causing the left main gear to buckle and fold underneath the fuselage. Another witness, Mr. Tom Slagel of Dillingham, was flying abeam runway 19, when he saw the accident airplane touch down and began to yaw to the left and right slightly. He continued to watch as the airplane began what he described as the beginning of a ground loop to the right. He said it appeared to him that the left main tire was excessively side loaded, and the left main landing gear subsequently collapsed. Damage to the accident airplane was observed on the left wing, and the tubular fuselage support structure for the left main landing gear. The FAA inspector noted that the 29 inch wheel had separated from the landing gear axle at the point where it attached to the Gar-Aero wheel adapters. The left main landing gear axle fractured, and the fracture surfaces were examined with a 20X eye loupe by the NTSB investigator-in-charge. The fracture surfaces were uniform in color and granular appearing, with multiple 45 degree shoulders. No evidence of a fatigue fracture was observed. The same airplane and pilot had been involved in a ground loop a few days earlier on April 30 at Kodiak, Alaska. In the earlier mishap, the airplane was reported to have received only minor damage. The Kodiak landing incident was also on a hard surfaced runway.

Probable Cause and Findings

failure of the pilot to maintain directional control during the landing, which resulted in an inadvertent ground loop/swerve.

 

Source: NTSB Aviation Accident Database

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