Accident Details
On November 4, 2020, at 1220 mountain standard time, a Remos Aircraft GMBH Fleugzebau GX, registration N87GX, was substantially damaged in an accident near Glendale, Arizona. The certificated flight instructor and student pilot on board were not injured. The flight was conducted as a Title 14 Code of Federal Regulations Part 91 personal flight.
The purpose of the flight was for the student pilot to practice takeoffs and landings. During a landing, the airplane veered left of the runway centerline. The flight instructor took control to prevent a runway excursion. Maneuvering the airplane back to the centerline proved difficult. A grinding noise and unusual vibration were then felt. The instructor managed to taxi the airplane to the nearest taxiway and shut down the engine.
Postaccident Examination
A postaccident examination revealed that the aluminum carry-through structure of the main landing gear had failed during the landing. A portion of the failed aluminum carry-through remained attached to the landing gear and breached the composite structure, entering the cabin floor under the passenger seat. Approximately 12 inches of the carry-through structure had separated from the airplane, allowing the horizontal stabilizer and elevator to skid on the runway surface and erode the composite structure.
The failed carry-through was sent to the National Transportation Safety Board's Material Laboratory. A senior materials engineer reported that the carry-through appeared to have failed in overstress. The fracture surfaces exhibited features consistent with overstress, and hardness and conductivity measurements were consistent with a material meeting minimum strength requirements.
Maintenance and Service Bulletin Compliance
A review of the airframe maintenance logbook indicated that all safety alerts and airworthiness directives had been complied with. On December 17, 2009, the manufacturer had issued Service Bulletin SB-002-landing-gear for the accident airplane. This service bulletin required inspection of the aluminum carry-through for the main landing gear immediately following any hard landing, within the next 50 landings, and during scheduled maintenance (100-hour and annual condition inspections).
During an interview, the recently hired Light Sport Repairman Maintainer reported that he had completed the required inspection for cracks, specifically near the weight reduction holes, on October 29, 2020. He recalled no visible cracks or signatures of deformation to the carry-through during that 100-hour inspection. The service bulletin specified replacement of the carry-through as soon as practical, but at the latest after detection of cracks or after 800 total landings, whichever occurred first. At the time of the inspection, the airplane had accumulated 402 estimated landings and 317.9 total airframe hours. At the time of the accident, the airplane had accumulated 437 estimated landings.
The investigation did not identify any mechanical malfunction or failure unrelated to the landing gear carry-through failure. The accident sequence involved a loss of directional control during landing, followed by the structural failure.