Aviation Accident Summaries

Aviation Accident Summary CHI07LA056

Belleville, IL, USA

Aircraft #1

N9284P

Piper PA-24-260B

Analysis

The pilot reported that after takeoff he selected landing gear-up, but the corresponding position light did not illuminate. He checked the landing gear motor circuit breaker and found it tripped. The pilot was unable to get the landing gear to fully extend or retract during subsequent attempts. The destination airport control tower verified that the landing gear was not fully extended during a fly-by after the pilot had attempted an emergency landing gear extension. The pilot decided to retract the landing gear as much as possible and perform a wheels-up landing in a grass area adjacent to a runway. The airplane sustained substantial damage to a fuselage bulkhead during landing. Inspection of the airplane showed that the right main landing gear was partially extended with its wheel and lower strut assembly rotated in the wheelwell. The bolt that attached the upper and lower portions of the torque link assembly was sheared in half. The lower torque link was jammed against the wheelwell structure, which restricted the movement of the entire landing gear assembly. The bolt fracture features were consistent with shear overstress, as a result of torsion during the action of the torque link assembly. The bolt fracture face did not contain any evidence of fatigue cracking. The separated bolt sections were seized within the upper and lower torque links, as a result of surface corrosion.

Factual Information

On December 28, 2006, at 1612 central standard time, a Piper PA-24-260B (Comanche), piloted by a commercial pilot, was substantially damaged while landing at Scott AFB/MidAmerica Airport (BLV), Belleville, Illinois. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot and his two passengers were not injured. The flight originated from Piatt County Airport (2K0), Monticello, Illinois, at 1507. The pilot reported that after takeoff he selected landing gear-up, but the corresponding position light did not illuminate. He checked the landing gear motor circuit breaker and found it tripped. He selected landing gear-down and reset the circuit breaker. The landing gear did not fully extend, as indicated by the position of the emergency extension handle and the position lights. The pilot again attempted to retract the landing gear, but it only retracted about 90-percent before the landing gear motor circuit breaker tripped. The pilot decided to continue to BLV where he planned to perform an emergency landing gear extension prior to landing. As the airplane neared BLV, the pilot attempted to lower the landing gear without success using the normal extension procedure. He then proceeded with the emergency landing gear extension procedure. The pilot was unable to get the landing gear to fully extend or retract during subsequent attempts. The control tower verified that the landing gear was not fully extended during a fly-by. The pilot decided to retract the landing gear as much as possible and perform a wheels-up landing in the grass area adjacent to runway 14. The airplane sustained substantial damage to a fuselage bulkhead during landing. Inspection of the airplane showed that the left main and nose landing gear were completely retracted into their respective wheelwells. The right main landing gear was partially extended with its wheel and lower strut assembly rotated in the wheelwell. The AN174-13 bolt (p/n 402-313) that attached the upper and lower portions of the torque link assembly (p/n 20735-03) was sheared in half. The lower torque link was jammed against the wheelwell structure, which restricted the movement of the entire landing gear assembly. The torque link assembly and bolt were sent to the National Transportation Safety Board's Materials Laboratory in Washington, D.C., for further examination. The bolt fracture features were consistent with shear overstress, as a result of torsion during the action of the torque link assembly. The bolt fracture face did not contain any evidence of fatigue cracking. The separated bolt sections were seized within the upper and lower torque links, as a result of surface corrosion.

Probable Cause and Findings

The failure of the torque link bolt which resulted in the right main landing gear strut scissors separating and becoming jammed in the wheel well. Contributing to the accident was the seized torque link bolt due to surface corrosion.

 

Source: NTSB Aviation Accident Database

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