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 regret to inform you that while flying a Mooney M20C, I experienced a sudden and unexpected electrical failure.
As a result, all electrical systems on the aircraft ceased to function, including the cockpit instrumentation, lights, and radios. Additionally, smoke began to emanate from the cockpit, further complicating the situation.
In response to this situation, I immediately began the process of identifying a suitable landing site. After carefully assessing my options, I decided to return to the departure airport, as it was the closest and most familiar landing site available.
I was able to safely land the aircraft without incident.
Once on the ground, I immediately shut down the engine and evacuated the aircraft.
Subsequent examination after landing revealed that the intake air filter was on fire and, with the assistance from the people on the ground, I was given a fire extinguisher and put out the fire. The police were called and the fire department both responded to the incident.
The next day during daylight hours the airport fire department investigated the incident. A qualified fire official revealed faulty wiring as a possible root cause of the electrical failure.
I can assure you that I followed all appropriate procedures and acted with the utmost caution and professionalism throughout this incident.
For the safety of aviation and other people, I will tell you how the problem arose from poor maintenance.
Two days before the flight I was inspecting the muffler and left the cabin heater cover over the muffler loose. The fumes escaped from a hole in the muffler and started a fire on the cabin heating duct under the generator.
This engine is not very fuel efficient and a great amount of fuel vapor got out of the exhaust unburned. Unfortunately, it was discovered in flight where a rich mixture had been used during takeoff.
Contributing factors: A nice day for an early spring flight and forgetting about the muffler heating problem. The heater was not needed since it was a hot day.
Corrective actions are not needed because this item gets inspected during annual maintenance and you only see the hole on the muffler if you remove the heater cover over the muffler.
Human factors affecting the quality of the muffler: It is hard to get parts for this old airplane. I asked the maintenance facility on the field, which is a Mooney authorized repair station, for a muffler and they told me that I should remove my muffler and send it for repair. I asked why, I just wanted a new muffler. The IA said that this muffler will get shaped to the engine and a new muffler will cause problems. This misinformation caused me not to replace the muffler and caused this incident.
The electrical issue I noticed probably was caused by the fire under the generator.
The aircraft is not airworthy, and it looks like it is not going to be flying for a while. The actions not to replace the muffler caused the problem.
Primary Problem: Human Factors
ACN: 1992806
These reports are for ALL of us to learn. These Snide type comments will cause pilots to take a pass on submitting anything. Constructive comments will help US ALL to learn. Just saying..
My first flight instructor, and best friend at the time, died in an aircraft crash while working as an airmail pilot for a small operation. The cause of the crash was asphyxiation of the pilot and ultimate flight into ground. The mechanical cause – replacement of the muffler with a defective one salvaged from a former crashed aircraft.
The design of cabin heat function using air circulated through chambers around the exhaust system is inherently dangerous and must be scrupulously inspected and maintained.
I write in memory of my friend, and hope that no one will ignore the situation, especially by using cost as the prime factor in decision making.
Corrective action in this case is ABSOLUTELY needed, as the single most critical point of failure has not been corrected – and that is the pilot himself. His decision to not replace the muffler didn’t cause this event – his decision to fly an aircraft that he KNEW was unairworthy caused this event. Unless he is a properly-rated mechanic, he should not have been messing with the muffler. A hole in a muffler will cause carbon monoxide poisoning, and is a no-fly item. The heat cover being left off shows a marked lack of attention to detail. Then flying with an overly-rich mixture? This pilot needs to take a long, in-depth look at themself, and REALLY figure out what went wrong. He introduced almost all of the dirty-dozen Human Factors INTO HIS OWN FLIGHT. If the pilot fails to learn from this, their next event will involve the FAA, the NTSB, and body bags.
Yep; you nailed it.
“Human factors affecting the quality of the muffler”….
Huh?
I admit I got a bit lost in the pilot’s wandering narrative, but according to the FAA 14 CFR Part 43, “Maintenance, Preventive Maintenance, Rebuilding, and Alteration, the holder of a pilot certificate issued under 14 CFR Part 61 may perform specified preventive maintenance on any aircraft owned or operated by that pilot, as long as the aircraft is not used under 14 CFR Part 121, 127, 129, or 135.”
IOW, if you’re not an A&P, you’re pretty much limited to the list of examples given in Part 43.
Knowing the muffler had issues to begin with, should’ve prevented this from happening.
Precisely
No CO detector, no fire extinguisher, a worn out muffler, and an unairworthy aircraft. I’m glad the reporter survived.