What happened
On January 26, 2023, a Cessna 340A, registered HB-LNW, departed Grenchen Airport for a proficiency check flight to Bern-Belp Airport. The flight was intended to be conducted under Instrument Flight Rules (IFR) with a return to Grenchen. During the flight, the crew performed a simulated engine failure during an instrument approach to runway 14, which was completed successfully.
Following a go-around, the crew entered the left pattern for runway 14 under Visual Flight Rules (VFR). The objective for the second approach was to simulate a more complex emergency scenario involving both a single-engine operation and a failure of the landing flaps. While the approach initially proceeded as expected, the aircraft experienced a hard landing upon touchdown. The crew proceeded with a planned touch-and-go maneuver and returned to Grenchen. Due to suspected damage, the crew flew at a low altitude over Grenchen to visually inspect the landing gear from the ground. Upon landing, significant damage was discovered on both the main landing gear and the wings.
The investigation
The investigation focused on the execution of the simulated emergency procedures and the operational risks associated with training in a real aircraft. The SUST examined the flight parameters, the weather conditions—which included light icing in the cloud layer—and the specific procedures outlined in the pilot's operating handbook. The investigation also reviewed the complexity of managing multiple simulated failures simultaneously.
Findings
- The second approach required the crew to manage two simultaneous emergency procedures: a simulated engine failure and a simulated inability to extend the landing flaps.
- The simultaneous application of these two emergency scenarios created a highly demanding flying task with very low tolerance for error.
- The crew was unable to successfully manage the increased workload and complexity during the landing phase.
- The incident highlights the inherent risks of practicing high-complexity emergency procedures in actual aircraft rather than in flight simulators.