What happened
On 20 July 2017, a Beech A36 Bonanza, registration G-JLHS, was conducting a private flight when it experienced a hard landing at Alderney Airport. During the impact, a momentary short circuit occurred at a stub terminal located on the aircraft's firewall. This electrical fault caused the master avionics power to shut down, and the systems remained inoperative.
Following the initial landing, the aircraft experienced several bounces before becoming airborne once more. The pilot initially departed toward the south. Due to the loss of radio functionality, the pilot was unable to establish contact with Alderney Tower to declare the situation or notify controllers of the intention to divert to Guernsey. The pilot eventually managed to contact Guernsey Tower using a mobile phone and proceeded to complete a successful landing at the Guernsey airfield.
The investigation
Investigators examined the electrical system of the aircraft to determine why the avionics failed to remain powered. A maintenance organisation in Guernsey inspected the electrical components and focused on the firewall area. The investigation established that the rubber boot, which is intended to cover the stub terminal on the firewall, was missing. This absence of protection allowed arcing to occur between the engine and the exposed stud, leading to the electrical interruption.