Incident Overview
On 20 July 2017 at 1110 UTC, a Beech A36 Bonanza (registration G-JLHS) operated by a private pilot made a hard landing at Alderney Airport. The aircraft, equipped with a single Continental Motors Corp IO-550-B piston engine, sustained no damage. Both crew members and the sole passenger were uninjured.
Avionics Failure
As a result of the hard landing, a momentary short circuit occurred at a stub terminal on the firewall which supplied master avionics power. This caused the avionics to turn off and remain off for the remainder of the flight.
Diversion and Landing
Following the hard landing, the aircraft bounced several times and became airborne again, departing initially to the south. Without radio communication, the pilot was unable to contact Alderney Tower (TWR) to advise of his intention to divert to Guernsey. While approaching Guernsey, the pilot used a mobile phone to contact Guernsey TWR before making a successful landing.
Maintenance Findings
A Guernsey maintenance organisation investigated the electrical problem. They identified that the rubber boot intended to cover the stub terminal on the firewall was missing. This absence allowed arcing between the engine and the exposed stud, causing the short circuit.