Incident Overview
On 6 April 2018 at 0743 UTC, a Diamond DA 42 M Twin Star (registration G-DOSB) operated on a training flight at Bournemouth Airport, Dorset, made a landing with the landing gear retracted. The aircraft slid to a halt on the runway, resulting in damage to the propellers, engine gearboxes, lower engine cowlings, and various underside panels. Both pilots, the student and instructor, were uninjured.
Flight History
The flight was preparatory for a multi-engine class rating test. After re-joining the circuit, the student pilot performed an approach with flaps configured normally, encountering turbulence and an estimated crosswind of 14 kt. A satisfactory touch-and-go landing was completed, followed by a turn onto the downwind leg for a flapless approach.
While on downwind, the student actioned the 'Pre Landing' checklist, which includes confirming the parking brake is off. He then began the 'Final Descent' checklist and believed he said "gear down" before reducing power and turning onto base leg. The instructor recalled that as the student placed a hand on the landing gear lever, both crew realized they had lost visual contact with a preceding aircraft. The instructor asked to continue downwind until the traffic was sighted.
On base leg, the instructor noticed the parking brake was on and pointed it out. The student thought the lever was off. They discussed that the parking brake lever functions opposite to adjacent heating controls: its aft position is labelled 'lock' (on), while the forward position is 'release' (off). The student released the brake, but the instructor remained distracted by the lever markings.
As the aircraft turned onto final approach, it was offset from the centreline. The instructor considered a go-around but decided to coach the student back to the centreline. While doing so, the student made large power changes to control airspeed, which was increasing. The instructor, occupied with monitoring, overlooked the required check of aircraft stability and landing configuration at 100 ft AAL.
Landing and Aftermath
Over the runway threshold, the student reduced power, and the aircraft touched down gently. Unusual noises were heard, and it became apparent the landing gear was up. The propellers struck the surface as the aircraft slid to a halt, with the underside of the engine cowlings and fuselage in contact with the runway. The instructor shut down systems, and both pilots opened the canopy and vacated. They observed the landing gear lever was in the up position, but the gear doors had opened and tyres were partially visible.
Crew Comments
The instructor stated that he and the student overlooked checking landing gear indications for three reasons: distraction from looking for traffic ahead, confusion from the parking brake mis-selection, and continuing an unstable approach which led to coaching and forgetting to check at 100 ft.
The student reflected that he might have been distracted by traffic or the parking brake position and might not have moved the landing gear lever. He noted that earlier in the flight and on previous flights, he had practiced simulated emergencies using 'touch drills' (touching levers without activating them). He suggested that under high workload, he may have touched the gear lever without actually moving it.
During the approach, the student observed airspeed increasing, which he attributed to power adjustments for crosswind or the flapless approach. After the accident, he realized that with the gear up, the aircraft created less drag, requiring less thrust.
The aircraft operator stipulates an 'Approach Gate' at 400 ft AAL where the student should call '400 stable' or '400 not stable, go-around'. One parameter to check is landing gear down with three green indicators. Neither crew member recalled this call. The student suspected he either forgot due to workload or made the call without checking the gear lever position. At 100 ft, he stated '100 landing', which he believed indicated he had convinced himself the gear was down. He noted that most of his previous experience was on fixed-gear aircraft, which may have influenced his decision-making.
Earlier, while practising an engine fire drill, the student recalled an intermittent aural warning from a remote cockpit speaker indicating gear up and one power lever at 17% or less. Neither pilot recalled this warning before the final touchdown.
Operator's Report and Recommendations
The aircraft operator's initial report suggested the parking brake may have been selected 'On' instead of the gear lever set to down. When noticed, this led to distraction and confusion due to the different operating directions of the parking brake lever and adjacent heating controls. The distraction prevented the instructor from effectively monitoring the student.
The operator noted it was possible the landing gear was partially or fully deployed and retracted after touchdown. Checks on the landing gear and aural warning system serviceability were planned when the aircraft is repaired. The operator also planned to review operating parameters and the aural warning system adequacy, and to consider incorporating labelled positions for the parking brake lever in checklists.
Other recommendations from the operator's internal report included:
- Reminding crews to complete entire checklists correctly without interruption, reviewing checklist completion methods, and providing guidance for interrupted checklists.
- Emphasizing the importance of 'Approach Gate' checks, and reminding instructors of the prime importance of monitoring students' actions at crucial stages.
- Reminding crews that a go-around is often the best course of action if an approach becomes unstable or rushed, and that unresolved situations should be dealt with at a safe altitude when capacity allows.