What happened
On 19 July 2018, a Flight Design CTSW, registration G-KUPP, was conducting a training flight from Redhill Aerodrome. Shortly after departing Runway 08R, the pilot noticed smoke and a burning smell emanating from the instrument console while climbing through 500 feet. The pilot declared a MAYDAY and initiated an immediate left turn to return to the airfield.
During the emergency circuit, the pilot experienced heat radiating from the central console onto their leg. Due to the density of the smoke, visibility of the airspeed indicator was compromised during the final approach. The aircraft landed halfway down the active runway, where airport fire services extinguished the fire using carbon dioxide. There were no fatalities and no injuries to the two occupants. The total duration of the flight was less than two minutes.
The investigation
Investigators examined the aircraft's instrument console and found evidence of previous modifications intended to accommodate new avionics. Specifically, the charge indicator lamp had been relocated from the upper right of the panel to the lower central section. The inspection of the wiring revealed poor workmanship, including wires that were excessively long, poorly supported, and utilized improper terminals.
Technical analysis determined that the wire supplying the charge lamp was subject to a short circuit. Because the wire was not shortened during the relocation of the lamp, the excess length was susceptible to damage. The investigation found that the wire had burned through, and the resulting high current—potentially up to 50 amps—generated enough heat to ignite the resin within the carbon/resin composite structure of the console. The fuel supply pipe and filter were also located in the rear of this console area.
Findings
- The fire was initiated by an electrical short circuit caused by damaged insulation on an over-length wire.
- The modification to relocate the charge indicator lamp left excess wiring that was prone to chafing or pinching.
- The high current resulting from the short circuit provided sufficient thermal energy to ignite the resin in the composite instrument panel.
- The poor standard of wiring following the modification contributed to the risk of electrical failure.