This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
I departed ZZZ in the Cessna 414 on an IFR flight plan with a planned cruising altitude of 17,000 feet.
I was the Pilot in Command (PIC) and the pilot flying (PF). I had a fellow pilot sitting in the copilot seat performing radio, checklist, and pilot monitoring (PM) assistance. We both possess an Airline Transport Pilot (ATP) certificate and we both fly for Part 121 airlines.
During vectors around multiple storm cells, we established a stable climb profile out of ZZZ.
The aircraft’s cabin was hot and stuffy so I turned on the electrically operated air conditioning (AC) unit which caused a significant draw on the electrical system. I also had the anti-collision, position and instrument panel lights on that are required for night navigation along with a BFG Stormscope unit, a communications/navigation radio, a Garmin 430 GPS unit, a DME unit and a transponder unit.
Climbing through 10,000 feet, I turned on the pitot heat anticipating a freezing temperature at 17,000 feet. At this point in the flight, the electrical system was operating near maximum capacity.
Climbing through 15,500 feet, my 6-pack instrument panel lights all went out at the same time without any circuit breaker tripping.
About 30 seconds later, the PM and I both smelled what we concurred to be burning wire fumes.
Although we did not see smoke or fire, we declared a “PAN PAN PAN” and diverted to ZZZ2.
The controllers at ZZZ2 re-designated our aircraft as a priority aircraft and committed Crash, Fire, Rescue (CFR) and police resources to our landing.
During the descent, we turned off the AC and pitot heat and noticed that the burning fumes smell was gone.
We landed at ZZZ2 without any problem.
Primary Problem: Aircraft