Bellanca 17-30A N39880 accident near Madison, Mississippi

Probable cause

The failure of a muffler weld due to inadequate maintenance, which resulted in a fire.

NTSB analysis

The pilot noticed smoke in the cockpit while on departure. He returned to land and when the smoke worsened during taxi, he stopped the airplane and shut down the engine. The pilot and passenger egressed the airplane and observed a fire in the engine compartment. They were not able to put out the fire with a fire extinguisher. The airplane sustained substantial damage to the forward fuselage.

Postaccident examination revealed the right-side exhaust system was fractured between the muffler and tailpipe. The investigation determined that a crack in the weld joining the aft ball tube to the aft muffler flange had previously failed, and a weld repair had been performed. Metallurgical examination determined that the repair weld had failed, allowing hot exhaust gases to escape onto the surrounding engine compartment components.

Maintenance records show the Airworthiness Directive (AD) calling for the repair weld to be inspected was complied with during the last annual inspection, just under a month and about 10 flight hours before the accident. The mechanic that completed the inspection was not aware of the AD requirement to spray the outside of the muffler with a penetrating oil to check for cracks, which most likely would have identified the muffler weld issue prior to the failure.

Text from the NTSB. Open the NTSB docket for CEN22LA256 for the full record.