Aviation Accident Summaries

Aviation Accident Summary FTW91FA158

TULSA, OK, USA

Aircraft #1

N817R

BEECH K35

Analysis

DURING ROUTINE MAINTENANCE, THE ENGINE WAS RUN UP TO FULL POWER WITH THE AIRPLANE TOW BAR ATTACHED. AS THE NOSE STRUT COMPRESSED, THE PROPELLER STRUCK THE TOW BAR. A SERVICE BULLETIN ADDRESSES THIS ISSUE STATING THAT THE ENGINE SHOULD BE DISASSEMBLED AND INSPECTED FOR DAMAGE. THE MAINTENANCE FACILITY DID NOT ADVISE THE OWNER OF THE EXTENT OF THE DAMAGE INCURRED. AS A RESULT OF THE PROPELLER STRIKE, THE CRANKSHAFT MAIN BEARINGS ROTATED IN THE SADDLES, FAILING MECHANICALLY. THIS RESULTED IN THE BLOCKAGE OF OIL PASSAGES AND THE SUBSEQUENT FAILURE OF THE NUMBER TWO CYLINDER CONNECTING ROD CAP BOLTS. TOTAL ENGINE FAILURE RESULTED. SUITABLE TERRAIN FOR THE FORCED LANDING WAS NOT AVAILABLE. IMPACT OCCURRED IN SOFT CULTIVATED TERRAIN.

Probable Cause and Findings

TOTAL POWER LOSS DUE TO FAILURE OF THE CRANKSHAFT BEARINGS AND CONNECTING ROD CAP BOLTS RESULTING FROM THE MAINTENANCE FACILITIES' FAILURE TO OVERHAUL THE ENGINE. A FACTOR WAS THE LACK OF SUITABLE TERRAIN FOR THE FORCED LANDING.

 

Source: NTSB Aviation Accident Database

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