LAKE BUTLER, FL, USA
N7443S
BUTLER AEROSTAR 601
SHORTLY AFTER LEVELING OFF AT 14,000 FT THE LEFT ENGINE QUIT. THE PILOT DIVERTED TO TAMPA, AND 34 MINUTES LATER THE RIGHT ENGINE QUIT. DURING THE SUBSEQUENT FORCED LANDING THE AIRPLANE COLLIDED WITH THE ROOF OF A COVERED SIDEWALK AND THEN TREES. TEARDOWN OF THE LEFT ENG REVEALED THAT THE SEAL BETWEEN THE EXHAUST FLANGE & TURBOCHARGER WAS NOT INSTALLED; BOLT CLAMP WAS FINGER TIGHT. HEAT HAD MELTED WIRING HARNESS & MAG GROUNDING LEADS INSULATION; BOTH 'P' LEADS WERE GROUNDED. PILOT STATED THAT AFTER LOSING THE LEFT ENG HE INITIATED A LEFT TANK TO RIGHT ENGINE CROSSFEED, AND AFTER 20 MINUTES OF SINGLE ENG FLIGHT IN THIS CONFIGURATION THE RIGHT ENG QUIT. FLIGHT MANUAL STATES TO LAND AS SOON AS POSSIBLE IN CASE OF ONE ENG FAILURE. IN ADDITION, IT WARNS THAT WHEN FLYING ON ONE ENG & CROSSFEEDING FUEL, ABSOLUTE COORDINATED FLIGHT MUST BE MAINTAINED TO PREVENT UNPORTING OF THE TANK'S FUEL PICKUP TUBE WHEN THE TANK IS NOT FULL.
INFLIGHT FAILURE OF THE LEFT ENGINE WHICH WAS CAUSED BY INADEQUATE MAINTENANCE AND INSPECTION BY COMPANY MAINTENANCE PERSONNEL RESULTING IN HEAT DAMAGED MAGNETO LEADS AS A RESULT OF A MISSING EXHAUST FLANGE-TO-TURBOCHARGER SEAL. IN ADDITION, THE INFLIGHT POWER LOSS OF THE RIGHT ENGINE WAS CAUSED BY THE PILOT'S FAILURE TO FOLLOW THE PROCEDURES IN THE AIRPLANE OPERATING HANDBOOK AND LAND AS SOON AS POSSIBLE RESULTING IN FUEL STARVATION OF THE RIGHT ENGINE. DARKNESS WAS A RELATED FACTOR.
Source: NTSB Aviation Accident Database
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