The Luscombe 8E was recently purchased by the pilot and delivered to Cortez Municipal Airport (KCEZ) by the flight instructor. After delivery, the pilot and flight instructor conducted flights over several days to familiarize the pilot with the airplane.
According to the pilot, on the day of the accident he conducted several landings without incident. The final takeoff and landing were conducted with the flight instructor manipulating the airplane’s flight controls. He said that the final landing was “very hard.”
The flight instructor reported that he landed on the runway centerline and as the airplane was rolling out, the right main landing gear collapsed.
He noted that the right seat position, where he was seated, did not have brakes installed.
During the landing, the right main landing gear collapsed. The airplane’s left wing was substantially damaged during the landing.
The failed right main landing gear was examined by the National Transportation Safety Board Materials Laboratory. That examination 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 tube thickness near the fracture had thinned from 0.040 inches to 0.025 inches.
On June 5, 2017, the FAA issued a special airworthiness information bulletin (SAIB), CE-17-14, to alert owners of several models of JGS Properties and Luscombe airplanes, including the model 8E, of a need for inspection to detect and correct corrosion inside the main landing gear legs.
According to the bulletin, internal surface treatment and regular inspection of the lower legs may help mitigate the corrosion-related gear failures. Compliance with a FAA SAIB is not mandatory for 14 CFR Part 91 operations.
The FAA recommended that owners and operators of the affected airplanes follow the inspection procedures outlined in 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.
The accident airplane did not appear to have a drain hole in this portion of the lower leg.
The FAA also urged using X ray or ultrasound inspection methods on the leg-to-axle joint to detect internal rust during initial or follow-on inspections of the gear leg.
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.
Probable Cause: Failure of the right main landing gear due to prolonged corrosion of the landing gear tube, which weakened the gear.
NTSB Identification: 192255
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This May 2023 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
