ATTALLA, AL, USA
N699DT
CESSNA 421B
THE AIRLINE TRANSPORT PILOT REPORTED THAT SHORTLY AFTER TAKEOFF FROM RUNWAY 36, HE HEARD A LOUD NOISE FROM THE LEFT ENGINE AREA, AND OBSERVED SMOKE TRAILING THE LEFT ENGINE NACELLE. HE CONFIRMED THAT THE LEFT ENGINE WAS LOSING POWER, AND HE FEATHERED THE LEFT PROPELLER. HE WAS UNABLE TO MAINTAIN ALTITUDE, AND THE AIRCRAFT WAS FORCE LANDED ON WOODED TERRAIN. THE AIRCRAFT CAUGHT FIRE ON THE GROUND AFTER COLLIDING WITH TREES AND WAS DESTROYED. AN INSPECTION OF THE LEFT ENGINE TURBOCHARGER REVEALED THAT THE ROTOR SHAFT WAS SEIZED, WITH EVIDENCE OF METAL TRANSFER TO THE BEARING JOURNALS.
On June 10, 1993, at about 1827 central daylight time, a Cessna 421B, N699DT, collided with trees and terrain following a reported engine power loss near Attalla, Alabama. The aircraft was destroyed by impact forces and fire. The airline transport pilot was not injured. The aircraft was operated under 14 CFR Part 91 by the pilot. Visual meteorological conditions existed at the time, and no flight plan was filed for the flight from Gadsden, Alabama to Huntsville, Alabama. The flight originated at about 1825. The pilot reported the following: Shortly after lifting off from runway 36 at the Gadsden Airport, he heard a loud noise from the left engine, and observed smoke trailing from the left engine nacelle. He confirmed that the left engine had lost power, and he feathered the propeller. He was unable to maintain altitude, and prepared for a forced landing in an open field. The aircraft collided with trees prior to reaching the field. The aircraft impacted the ground, and caught fire. The pilot exited the aircraft without injury. The left engine was sent to the manufacturer's facility in Mobile, Alabama, where a disassembly and inspection were performed. A copy of the inspection report is included as an attachment to this report (see Teledyne Continental Motors Analytical Inspection Report). The left engine turbocharger was sent to the manufacturer's facility in Torrence, California, where a disassembly and inspection were performed. The inspection revealed that the turbocharger rotor could not be manually rotated. The rotor shaft was extracted from the centerbody, and both bearings were fused to the shaft. The bearings were removed from the shaft, exposing evidence of metal transfer to the bearing journals. For a detailed description of the turbocharger disassembly and inspection, refer to "NTSB Turbocharger Group Chairman Factual Report", attached to this report.
THE FAILURE OF THE LEFT ENGINE TURBOCHARGER DUE TO ROTOR SHAFT SEIZURE, WHICH RESULTED IN A LOSS OF ENGINE POWER.
Source: NTSB Aviation Accident Database
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