NTSB Identification: NYC95FA049.
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Accident occurred Monday, January 09, 1995 in WEST PALM BEACH, FL
Probable Cause Approval Date: 06/07/1996
Aircraft: BEECH G35, registration: N32TS
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The airplane was seen flying erratically, in a rapid descent, with smoke coming from the engine compartment and flames coming from the airplane's right side. Subsequently, the airplane crashed/landed and burned. An investigation revealed that the #1 cylinder had separated from the engine. Examination of the #1 cylinder revealed the upper crankcase thru-bolt at the 10 o'clock position had failed in fatigue below the cylinder deck surface. The lower thru-bolt at the cylinder pad's 8 o'clock position was intact; however, the nut was missing and the threads were battered and polished. The cylinder had 6 deck studs in addition to the thru-bolts. The studs at the 11 and 1 o'clock positions were missing; the studs at the 5 and 7 o'clock positions failed in fatigue; and the studs at the 2 and 4 o'clock positions were fractured with the fractured ends battered. Also, a silicon sealant (RTV) had been used on the thru-bolt threads, though not recommended by the manufacturer. The remaining thru-bolts were examined for tightness using a torque wrench; all were found undertorqued. During a top overhaul of the engine, about 85 flight hours before the accident, all of the cylinders had been removed and reinstalled.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Improper top overhaul by maintenance personnel, and improperly torqued crackcase thru-bolts and cylinder deck studs at the number one cylinder, which led to fatigue failure of four of the bolts, failure and/or separation of the number one cylinder, and a subsequent fire. Full narrative available
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