What happened
On 20 March 2020, a Beechcraft Super King Air 200, registration G-FLYW, was conducting a recurrent training flight at Exeter Airport. The flight, which originated from Bristol Airport, involved a trainee pilot and a commander acting as a Type Rating Examiner. The flight profile included general handling and simulated single-engine approaches.
During the second GNSS approach, performed in a simulated single-engine configuration, the crew extended the downwind leg to maintain separation from preceding traffic. The crew reported selecting the landing gear down and recalled seeing the three green lights indicating the gear was locked. However, as the aircraft flared for touchdown, a loud metallic noise was heard, and the propellers struck the runway. The crew immediately initiated a go-around.
Following the strike, the crew attempted to lower the landing gear using the normal system, but it failed to extend. They successfully deployed the gear using the emergency mechanism and subsequently landed at Exeter. The aircraft sustained propeller damage, engine shock-loading, and minor fuselage damage.
The investigation
The AAIB investigation focused on why the aircraft touched down with the gear retracted despite the crew's recollection of a successful gear extension. The investigation examined the aircraft's electrical control unit and the landing gear warning system.
Engineers discovered a fault in the undercarriage electrical control system: a damaged down-select contactor prevented the gear from lowering when selected. Once this component was replaced, the system functioned normally. The investigation also looked into Air Traffic Control (ATC) communications, noting that an airfield operations vehicle had observed the gear was up and attempted to alert ATC, but the message was not acknowledged due to the use of a UHF radio loudspeaker rather than a headset.
Findings
- The pilots believed they had seen the green lights, but it is possible they saw what they expected to see.
- The uncommanded landing gear retraction could not be definitively proven, as the system design prevents the gear from raising itself when the handle is in the down position.
- It is possible the landing gear simply failed to extend when selected down due to the faulty contactor.
- The landing gear warning horn may not have activated because the power lever positions during the approach were high enough to be outside the alert trigger zone.
- Communication gaps between airfield personnel and ATC contributed to a lack of situational awareness regarding the aircraft's status.