What happened
On July 7, 2019, a Reims Aviation SA F177RG, registration LN-ALK, was performing a takeoff from runway 12 at Kjeller Airport (ENKJ). The flight was a private operation. During the takeoff roll, once the aircraft reached approximately 45 knots, the pilot noticed the nose gear beginning to retract. Reacting to the sudden loss of gear support, the pilot pulled back on the control stick to maintain the nose position and simultaneously reduced throttle to abort the takeoff.
Following the retraction of the nose gear, the main landing gear also retracted. The aircraft subsequently slid on its belly for approximately 210 meters before coming to a halt near the airport fire station. The aircraft traveled a total of about 530 meters from the start of the takeoff roll. The incident resulted in no injuries to the pilot, but the aircraft sustained damage to the propeller, the nose gear doors, and the fuselage belly.
The investigation
Investigators from the Norwegian Safety Investigation Authority (NSIA) examined the aircraft's landing gear mechanism and the pilot's procedures. Functional tests revealed that the landing gear could be extended and indicated as locked even if the gear handle was not fully seated in its detent. Specifically, if the handle was positioned just a few millimeters above the locked position, the wheels would still deploy and show green lights.
The investigation also looked into how the gear handle moved to the up position. While several scenarios were considered, investigators determined that the most likely cause was that the handle was left unlatched after a previous landing. During the subsequent shutdown, a passenger had placed a headset on the throttle. When the pilot moved the headset to the control stick, he inadvertently bumped the gear handle into the up position.
Findings
- The landing gear handle was not properly secured in the locked detent following a prior landing.
- The aircraft's design allowed the gear to appear locked even when the handle was not fully engaged.
- The pilot's use of a non-standard, personalized checklist led to the omission of the landing gear check during the engine start sequence.
- The pilot's movement of a headset from the throttle to the control stick likely bumped the gear handle into the retracted position.
- The safety switch in the nose gear strut, which prevents retraction while weight is on the wheels, did not trigger until the aircraft generated enough lift to relieve pressure from the nose gear.