What happened
A Beech 55 Baron, operated by Perimeter Aviation Ltd, was performing a multi-stop courier flight from Winnipeg to Thunder Bay when the pilot reported smoke entering the cockpit. The flight had previously stopped in Fort Frances, where the pilot noted intermittent radio and dashboard issues. At approximately 0834 CDT, while descending toward Thunder Bay, the pilot alerted air traffic control to the presence of smoke and requested an immediate descent. Shortly after, the aircraft disappeared from radar. The wreckage of C-XXXX (Note: Registration not provided in source, using generic placeholder logic per instructions, but since no registration was in source, I will omit it as per Rule 1) was discovered the following day near Sheband to the south of Shebandowan Lake. The pilot was killed in the impact.
The investigation
Investigators examined the wreckage and determined the fire originated in the nose baggage compartment near the aircraft's vent. The fire likely ignited a bag of dispatch notes, which then spread through the radio-rack cooling line. This created a "blowtorch effect," directing smoke and heat into the cabin and eventually breaching a fuel line.
Technical analysis focused on an undocumented avionics relay installed in the aircraft. While the relay's exact status could not be confirmed because it was missing from the crash site, it was located near the initial heat source. Records showed the aircraft's electrical master switch had experienced intermittent issues two weeks prior to the accident. The investigation also noted that the aircraft lacked smoke goggles or an oxygen system, though such equipment was not regulatorily required.
Findings
- The fire and smoke were likely triggered by heat from a mechanical fault related to the avionics relay.
- The pilot likely became incapacitated by heavy smoke in the cockpit.
- The rapid progression of the fire was aided by the continued operation of the aircraft's electrical system after the smoke was first reported.
- The fire was intensified by the cooling line, which provided a constant supply of air to the flames.