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NTSB Report
August 25, 1991 · Beech K35 · N817R
Tulsa, OK
Overview
Report Status
Probable Cause
Event Type
Accident
Date
August 25, 1991
Injury Outcomes
2 injuries (2 serious injuries)
Location
Tulsa, OK
Aircraft
Beech K35
Tail Number
N817R
Operator
Hershel Maurer
Injuries
Serious
Aircraft Damage
Substantial
NTSB Number
FTW91FA158
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.
NTSB Probable Cause
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.
Full Narrative
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.
Flight
Event TypeAccident
Event Time12:56 CDT
Nearest Airport0nm N
Runway0
Flight Plan FiledIFR
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBeech K35
Tail NumberN817R
Aircraft CategoryAir
DamageSubstantial
OperatorHershel Maurer
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsContinental · IO-470-C · Reciprocating · 250
Seats4
People & Injuries
Injury Summary2 injuries (2 serious injuries)
Fatal0
Serious2
Minor0
Uninjured0
Total2
Crew 1Age 52 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind180° @ 10 kt
Visibility3 sm
CeilingBroken clouds 5000 ft
Temperature / Dew Point0 C
Altimeter0
Weather SourcePILO