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NTSB Report
April 16, 1986 · Bell UH-1B · N910PD
Chowchilla, CA
Overview
Report Status
Preliminary report
Event Type
Accident
Date
April 16, 1986
Injury Outcomes
1 injury (1 minor injury)
Location
Chowchilla, CA
Aircraft
Bell UH-1B
Tail Number
N910PD
Operator
San Joaquin Helicopter
Injuries
Minor
Aircraft Damage
Destroyed
NTSB Number
LAX86DVA06
WHILE RETURNING FROM A SPRAYING OPERATION THE PLT OBSERVED THAT THE MAIN TRANSMISSION OIL PRESSURE GAGE INDICATED ZERO. THE PLT REPORTED THAT THE ENGINE MASTER CAUTION DID NOT ILLUMINATE AND THAT THE OIL TEMPERATURE GAGE WAS NORMAL. THE PLT STATED THAT HE DECIDED THAT THE OIL PRESSURE GAGE WAS FAULTY AND ELECTED TO CONTINUE THE FLT. ABOUT 5 MINUTES LATER, THE TRANSMISSION OIL TEMP GAGE BEGAN TO RISE RAPIDLY.THE HELICOPTER BEGAN TO SHAKE VIOLENTLY AND THE MAIN ROTOR RPM BEGAN TO DECAY. THE PLT, UNABLE TO PERFORM AN AUTOROTATION DUE TO LOW ROTOR RPM EXECUTED A POWER ON LANDING, AND THE HELICOPTER ROLLED OVER AT IMPACT. POST ACCIDENT INVESTIGATION DISCLOSED THE OIL COLLER HOUSING GASKET WAS DAMAGED AND THE TRANSMISSION OIL RESERVOIR DID NOT CONTAIN ANY OIL. THE TRANSMISSION OUTER HOUSING AND PLANETARY GEARS EXHIBITED HIGH TEMPERATURE DISTRESS.
Full Narrative
WHILE RETURNING FROM A SPRAYING OPERATION THE PLT OBSERVED THAT THE MAIN TRANSMISSION OIL PRESSURE GAGE INDICATED ZERO. THE PLT REPORTED THAT THE ENGINE MASTER CAUTION DID NOT ILLUMINATE AND THAT THE OIL TEMPERATURE GAGE WAS NORMAL. THE PLT STATED THAT HE DECIDED THAT THE OIL PRESSURE GAGE WAS FAULTY AND ELECTED TO CONTINUE THE FLT. ABOUT 5 MINUTES LATER, THE TRANSMISSION OIL TEMP GAGE BEGAN TO RISE RAPIDLY.THE HELICOPTER BEGAN TO SHAKE VIOLENTLY AND THE MAIN ROTOR RPM BEGAN TO DECAY. THE PLT, UNABLE TO PERFORM AN AUTOROTATION DUE TO LOW ROTOR RPM EXECUTED A POWER ON LANDING, AND THE HELICOPTER ROLLED OVER AT IMPACT. POST ACCIDENT INVESTIGATION DISCLOSED THE OIL COLLER HOUSING GASKET WAS DAMAGED AND THE TRANSMISSION OIL RESERVOIR DID NOT CONTAIN ANY OIL. THE TRANSMISSION OUTER HOUSING AND PLANETARY GEARS EXHIBITED HIGH TEMPERATURE DISTRESS.
Flight
Event TypeAccident
Event Time11:24 PST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell UH-1B
Tail NumberN910PD
Aircraft CategoryHeli
DamageDestroyed
OperatorSan Joaquin Helicopter
Operating RulePart 91
Engines1
Engine TypeTurboshaft
Engine DetailsLycoming · T53-L11D · Turboshaft · 1100
Seats2
People & Injuries
Injury Summary1 injury (1 minor injury)
Fatal0
Serious0
Minor1
Uninjured0
Total1
Crew 1Age 36 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility15 sm
CeilingNone
Temperature / Dew Point63 F / 37 C
Altimeter30.00 inHg
Observation Time03:50
Weather SourceWFAC