2016 Reims Aviation F177RG accident at Rakkestad Airport (LN-ALK)

Overview and Flight Details On 21 May 2016, a Reims Aviation SA F177RG with registration LN-ALK was involved in an accident at Rakkestad Airport, Åstorp (ENRK). The aircraft, built in 1976 and powered by a Lycoming IO-360-A1B6D engine, was operated by Flyklubben Øst. The flight was a private club training flight conducted in daylight under visual meteorological conditions. The weather was light cloud at 3,000 feet with a wind from 200 degrees at approximately 10 knots. ## Accident Description The flight was a training exercise involving landing circuits and air work, with an instructor and a student pilot on board. After departing Rakkestad, the aircraft proceeded to Rygge for three touch-and-go landings before returning to Rakkestad for simulated engine-failure training. During the third landing attempt, the student pilot and instructor confirmed the landing gear indicator light was green and visually verified the main wheels were down. As the aircraft rolled out on final, the student pilot set full flaps. The student did not notice anything unusual until the nose lowered after landing. The propeller struck the runway, and both occupants braked to stop the aircraft. The aircraft drifted to the right and came to rest on the grass just outside the runway edge. Both the student and instructor evacuated the aircraft uninjured. ## Investigation Findings Video footage from the airport showed the main wheels extended while the nose gear was retracted, with the main wheels appearing not fully extended. After the accident, the aircraft was placed on jacks and the landing gear was tested. No faults were found during the test runs, and all wheels extended and retracted as prescribed. The extension to the down and locked position took approximately 15 seconds. During testing, it was discovered that the landing gear aural warning operated opposite to its intended function. The warning was designed to sound when the wheels were not down and locked while the throttle was retarded to a manifold pressure below approximately 12 inches. However, the warning sounded when the wheels were not down and locked while the throttle was advanced to a manifold pressure above 12 inches. Neither occupant heard the aural signal during the flight. ## Probable Cause The investigation concluded that a probable scenario was that the landing gear handle was inadvertently raised during final on the third circuit, possibly as a reflex action, and then lowered again shortly afterward. This was consistent with the video footage and the crew's account that the gear was down and locked with a green light indication just before the key point. The faulty aural warning system removed a final barrier to detecting that the landing gear was not fully extended. The fault most likely occurred during maintenance work on the warning system and would have been detected by a thorough final check of the landing gear system.