Incident Overview
On 10 November 2019, at 11:46 local time, a Bombardier CL600-2B16 (Challenger 601-3A) aircraft, registration N227WG, departed from Adolfo Suárez Madrid-Barajas Airport (LEMD, Spain) on a flight to Nottingham East Midlands Airport (EGNX, United Kingdom). The flight crew consisted of a pilot-in-command and a co-pilot.
While climbing to 29,000 feet, the crew detected smoke and the smell of electrical fire emanating from behind the instrument panel on the right side of the cockpit. At 12:03, they declared an emergency and initiated a return to the departure airport. The aircraft landed safely on runway 32L at 12:21 and taxied under its own power to the assigned stand, escorted by the airport fire service.
Aircraft and Crew
The aircraft was operated by Flying M, LLC and was engaged in a non-commercial private flight under instrument flight rules. The pilot-in-command held a U.S. FAA Airline Transport Pilot certificate with multi-engine land ratings for multiple aircraft types, including the CL-600. The co-pilot's information was not specified. Both crew members were uninjured. No passengers were on board.
Damage
Inspection after the event revealed burned wires in the area behind the right instrument panel. Further examination identified damage due to overheating and electrical arcing in a terminal board assembly, which is part of the right-hand windshield heating system. The terminal board itself, some wiring, and the surrounding thermal blanket were damaged. No other damage was found.
Investigation Findings
The investigation determined that the presence of smoke in the cockpit forced the crew to declare an emergency and return to the airport. Loose wiring connections were found on the terminal board assembly. These connections resulted in overheating that damaged wiring and burned the thermal blanket, generating the smoke. The available evidence did not indicate a sustained fire.
Probable Cause
The probable cause of the incident was loose wiring connections on a terminal board assembly of the right-hand windshield heating system, located behind the instrument panel on the right side of the cockpit, which led to overheating damage and smoke.