What happened
On 21 August 2009, a Cessna Citation Mustang, registration PH-TXI, was conducting a training flight at Cambridge Airport. During the downwind leg of the circuit, the landing gear was not selected to the down position. Although a landing gear warning horn sounded during this phase, the commander silenced the alarm and believed the system had not reset.
As the aircraft progressed to the final approach, the co-pilot experienced difficulty reducing speed toward VREF due to the aircraft being configured with takeoff/approach flaps rather than landing flaps. During the flare, a grinding noise was heard from the rear of the aircraft, and the tail made contact with the runway. The co-pilot applied power to prevent further contact, at which point the commander took control and initiated a go-around. The aircraft subsequently completed another circuit and landed safely.
The investigation
Investigators examined the aircraft's landing gear warning system and the crew's cockpit procedures. An inspection of the PH-TXI revealed that while the landing gear warning system was fully functional, the flaps were stuck in the takeoff/approach position.
Evidence from an airport tower witness confirmed seeing the aircraft's tail contact the runway, accompanied by a puff of white smoke. The investigation also focused on the crew's use of checklists. The commander performed the landing checklist from memory rather than using the standard challenge and response method, which prevented the omission of the landing gear extension from being identified.
Findings
- The landing gear was not extended during the downwind leg.
- The landing checklist was not performed using the challenge and response technique, resulting in the loss of an opportunity to detect the gear omission.
- The commander's decision to silence the initial warning on the downwind leg meant that if the system had reset, the crew was unaware of the unconfigured state.
- The aircraft sustained damage to the underside, antenna, drain masts, and flap hinges.