Pilot Debrief

BELLANCA 17-30A near Madison, MS — 2022-06-16

Final reportCEN22LA256
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Date
2022-06-16
Location
Madison, MS, USA
Airport
MBO
Aircraft
BELLANCA 17-30A
Registration
N39880
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Taxi

Probable cause

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

NTSB narrative

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.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspection of the exhaust system welds prior to the flight could have prevented the failure.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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