CHI86IA034

Factual narrative

DURING CLIMB A BANG WAS HEARD AND THE AIRCRAFT SHUDDERED. THE CREW STATED THAT THE NUMBER THREE ENGINE OIL PRESSURE AND OIL QUANTITY INDICATED LOW. THE FIRE WARNING LIGHT AND BELL ACTIVVATED. THE ENGINE WAS SHUT DOWN AND THE AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. POSTFLIGHT INSPECTION REVEALED THE OUTBOARD COWLING OF THE NUMBER THREE ENGINE HAD SEPARATED. THE COWLING WAS FOUND IN A SUBURB TEN MILES SOUTHWEST OF THE AIRPORT. ENGINE TEARDOWN REVEALED A CRACK IN A VENT LINE STRUT IN THE DIFFUSER AREA ALLOWING BLEED AIR TO IGNITE OIL IN THE NUMBER THREE BEARING AREA. PRESSURE FORCED THE FIRE TO VENT THROUGH THE COMPARTMENT BREATHER AIR TUBE DISINTEGRATING THE MAIN BEARING BREATHER TUGE ELBOW. THE FORCE OF THE EXPLOSION AT THE DISINTEGRATING ELBOW BLEW THE OUTBOARD COWLING OFF. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12