Mufflers And Exhausts

The following is derived from maintenance facility submissions to the FAA’s Service Difficulty Reports database.

Editorial Staff

Sunday, September 29, 2024 at 05:00 AM ET

Verified

Key Takeaways:

Exhaust system components across various aircraft types (Cessna, Piper, Tecnam) are prone to failures, including cracks in mufflers, flanges, or pipes, pulled spot welds, and deteriorated ball joints.
These failures often result in exhaust gas leaks, which can lead to carbon monoxide warnings inside the cabin and compromise the aircraft's heating system.
Incidents demonstrate that such defects can occur even at relatively low part total times, as well as on components with unknown or longer service.
Some critical defects, like cracks in certain muffler areas, may not be visible without component removal, posing a challenge for routine inspections.

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Cessna 150L

Cracked Flange

During a scheduled inspection, a crack was found at the forward muffler flange. Crack is approximately 75 percent around the circumference. There is separation along the crack. Exhaust trails were found inside shroud and well down into hot-air ducting. Muffler identified as having three small pin holes in 2008. Heat system incapacitated at that time for safety reasons; muffler remained in service.