Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Workload; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Strong burning smell like hot wires shortly after departure. Since bleed air (heater) was on; my first step was to turn bleed air off assuming that is likely engine fumes. The switch would not turn off air; and hot air continued to enter and smell persisted. Thermostat control also would not change the air flow. Since the smell was abnormal and stronger than a common smell of TKS entering the engine (the TKS system was not used); I elected to return to ZZZ which had airport fire facilities and was only a few minutes away. In the event that were was a fire or something was about to catch fire; I elected to request priority handling and executed the in cabin fire checklist. Upon landing at ZZZ; no further indication of fire was present and I meet the airport fire on the ramp. Their investigation did not find anything that was or had been burning. Aircraft was secured on the ramp for inspection by a mechanic.
C-208 Captain reported a burning odor during initial climb resulting in a return to the departure airport.