Piper PA-38-112 Landing Gear Failure During Training Flight

Incident Overview and Flight Details On November 26, 2009, a Piper PA-38-112 was conducting training flights at the Cerro Azul runway, located four minutes from José Joaquín de Olmedo Airport in Guayaquil. The aircraft departed at 12:56 UTC with a pilot instructor and a student pilot on board. After the second landing, the instructor reported feeling a slight impact on the underside of the aircraft. Initially attributing the impact to contact with a pile of old tires at the runway threshold, the instructor continued the training session. During a subsequent landing attempt, an unusual noise prompted the instructor to suspend the flight and return to the base of operations. As the aircraft approached the runway at Guayaquil, the noise recurred, leading the pilot to execute a go-around and request a visual inspection from the control tower. The controller informed the pilot that the main landing gear was missing. The pilot then circled the airport to consume fuel and executed a successful landing without the main landing gear. No injuries were reported to the two occupants, and no third-party damage occurred. The aircraft sustained damage to the lower fuselage and the flaps on both wings during the final landing. ## Aircraft and Maintenance Information The aircraft held a valid airworthiness certificate. The main landing gear attachment bolts, part number AGNH-14A, were replaced on August 7, 2009, when the aircraft had 5,536.1 hours of service, in compliance with Service Bulletin 673B. The maintenance program, airworthiness directives, and component change controls were verified without findings. No prior reports of malfunctions were found in the flight logs. The pilot in command was a 29-year-old Ecuadorean holding a Commercial Pilot License and a valid Class 2 medical certificate. The pilot had a total of 898.3 flight hours, including 130.0 hours in the Piper PA-38 and 448.3 hours as an instructor. ## Investigation Findings and Probable Cause Field investigations revealed that the bolts securing the main landing gear to the aircraft structure were broken. Fracture analysis indicated failure due to over-stress, meaning the landing gear was subjected to forces exceeding the resistance limits of the bolts during the second landing. The investigation found no evidence that the pile of tires at the Cerro Azul runway threshold had been subjected to a force consistent with contact from the aircraft's landing gear. The unusual noise heard during the approach was caused by loose fuselage panels rubbing after the landing gear detached. The main landing gear remained in its housings, held by the aircraft's weight, until lift-off speed was reached, at which point the pressure was released and the gear separated. The right main landing gear fell two meters from threshold 15 of the Cerro Azul runway, while the left main landing gear was not located. The investigation concluded that the bolts broke due to forces generated during a hard landing. The probable cause of the accident was the inappropriate operation of the aircraft during the second landing of the student pilot's training period.