Luscombe 8E N2515K accident near Cortez, Colorado

Probable cause

Failure of the right main landing gear due to prolonged corrosion of the landing gear tube, which weakened the gear.

NTSB analysis

The conventional geared airplane’s right main landing gear collapsed during landing and the airplane’s left wing sustained substantial damage. The pilot reported that the flight instructor performed the final landing and that the landing was very hard. The flight instructor reported that he landed on centerline and as the airplane was rolling out the right main landing gear collapsed. He noted that there were no brakes in the right seat pilot station where he was located.

Metallurgical examination of the failed landing gear revealed corrosion on the inside of the main landing gear tube in the area where it was welded to the wheel axle. The corrosion progressively thinned the leg tube walls over time and caused pitting and microcracking on the tube interior. The combination of missing material, pitting, and microcracks led to an overstress fracture of the leg at this location on the final landing, which led to two other subsequent overstress fractures.

The Federal Aviation Administration issued a special airworthiness information bulletin (SAIB), CE-17-14, to alert operators of this and other similar model airplanes of the need to inspect and address corrosion issues on main landing gear. The SAIB recommended following the procedures of the Don Luscombe Aviation History Foundation Service Recommendation No. 4, dated Jan. 22, 1996, which provided instructions for installing a drain hole in the lower portion of the leg, performing repetitive inspections of the gear legs for corrosion, and cleaning and sealing the gear legs’ internal surfaces. Compliance with the SAIB is not mandatory.

Limited maintenance records were available during the investigation; however, the most recent annual inspection entry did not indicate that the landing gear were inspected for corrosion. The fractured main landing gear did not have drain holes as noted in the service recommendation, indicating that that procedures in the service recommendation had not been performed.

Based on the available evidence the accident was the result of failure of the right main landing gear leg due to weakening from prolonged internal corrosion of the landing gear tube, which weakened the leg.

Text from the NTSB. Open the NTSB docket for CEN23LA208 for the full record.