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NTSB Report
September 18, 1986 · Hiller UH-12E · N688SB
Lemoore, CA
Overview
Report Status
Preliminary report
Event Type
Accident
Date
September 18, 1986
Injury Outcomes
1 injury (1 minor injury)
Location
Lemoore, CA
Aircraft
Hiller UH-12E
Tail Number
N688SB
Operator
West Farm Air
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
LAX86FVA14
THE PLT REPTD THAT WHILE RETURNING TO THE LOADING AREA AFTER SPRAYING A FIELD, HE HEARD A LOUD POP EMANATING FROM THE ENGINE COMPARTMENT. SHORTLY THEREAFTER HE OBSERVED A FIRE IN THE ENGINE COMPARTMENT AND LOST FORWARD AND AFT CONTROL OF THE HELICOPTER. THE PLT IMMEDIATELY EXECUTED AN AUTOROTATION. THE HELICOPTER ROLLED OVER ONTO ITS SIDE ON TOUCH DOWN. THE POST-ACCIDENT INVESTIGATION ENGINE EXAMINATION DISCLOSED THAT THE NUMBER 3 CONNECTING ROD BOLTS FAILED. FURTHER EXAMINATION REVEALED THAT THE REMAINING CON ROD BOLTS TORQUE VALUES WERE ABT 50% LESS THAN THE REQUIRED VALUES.
Full Narrative
THE PLT REPTD THAT WHILE RETURNING TO THE LOADING AREA AFTER SPRAYING A FIELD, HE HEARD A LOUD POP EMANATING FROM THE ENGINE COMPARTMENT. SHORTLY THEREAFTER HE OBSERVED A FIRE IN THE ENGINE COMPARTMENT AND LOST FORWARD AND AFT CONTROL OF THE HELICOPTER. THE PLT IMMEDIATELY EXECUTED AN AUTOROTATION. THE HELICOPTER ROLLED OVER ONTO ITS SIDE ON TOUCH DOWN. THE POST-ACCIDENT INVESTIGATION ENGINE EXAMINATION DISCLOSED THAT THE NUMBER 3 CONNECTING ROD BOLTS FAILED. FURTHER EXAMINATION REVEALED THAT THE REMAINING CON ROD BOLTS TORQUE VALUES WERE ABT 50% LESS THAN THE REQUIRED VALUES.
Flight
Event TypeAccident
Event Time05:30 PDT
Nearest AirportLemore Nas (5nm W)
Runway0
Flight Plan FiledNone
Aircraft FireBoth
Aircraft ExplosionBoth
Aircraft
AircraftHiller UH-12E
Tail NumberN688SB
Aircraft CategoryHeli
DamageSubstantial
OperatorWest Farm Air
Operating RulePart 137
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · VO-540-C2A · Reciprocating · 305
Seats2
People & Injuries
Injury Summary1 injury (1 minor injury)
Fatal0
Serious0
Minor1
Uninjured0
Total1
Crew 1Age 41 · Second Class
Conditions
ConditionsVMC
LightDark Night
WindCalm
Visibility7 sm
CeilingNone
Temperature / Dew Point0 C / 0 C
Altimeter0
Weather SourcePILO