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NTSB Report
July 16, 1990 · Sikorsky S-58BT · N439DS
Ovando, MT
Overview
Report Status
Probable Cause
Event Type
Accident
Date
July 16, 1990
Injury Outcomes
No injuries (1 uninjured)
Location
Ovando, MT
Aircraft
Sikorsky S-58BT
Tail Number
N439DS
Operator
Skyline Helicopters
Injuries
None
Aircraft Damage
Substantial
NTSB Number
SEA90LA137
DURING AN EXTERNAL LOAD LOGGING OPERATION, THE PILOT HAD JUST TAKEN OFF FROM REFUELING AND WAS PREPARING FOR ANOTHER LOAD PICK- UP WHEN THE NUMBER ONE ENGINE LOST POWER AND FLAMES WERE OBSERVED SHOTTING OUT FROM THE EXHAUST. THE PILOT TRIED TO FLY THE HELICOPTER ON ONE ENGINE TO A LANDING AREA, HOWEVER, RPM WAS DROPPING. THE PILOT INITIATED AN AUTOROTATION WHICH RESULTED IN A HARD LANDING.
NTSB Probable Cause
THE PILOT DID NOT MAINTAIN ROTOR RPM AFTER A COMPRESSOR ASSEMBLY BLADE FAILURE. A RELATED FACTOR WAS AN INADEQUATE AUTOROTATION RESULTING IN A HARD LANDING.
Full Narrative
DURING AN EXTERNAL LOAD LOGGING OPERATION, THE PILOT HAD JUST TAKEN OFF FROM REFUELING AND WAS PREPARING FOR ANOTHER LOAD PICK- UP WHEN THE NUMBER ONE ENGINE LOST POWER AND FLAMES WERE OBSERVED SHOTTING OUT FROM THE EXHAUST. THE PILOT TRIED TO FLY THE HELICOPTER ON ONE ENGINE TO A LANDING AREA, HOWEVER, RPM WAS DROPPING. THE PILOT INITIATED AN AUTOROTATION WHICH RESULTED IN A HARD LANDING.
Flight
Event TypeAccident
Event Time10:30 MDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftSikorsky S-58BT
Tail NumberN439DS
Aircraft CategoryHeli
DamageSubstantial
OperatorSkyline Helicopters
Operating RulePart 133
Engines2
Engine TypeTurboshaft
Engine DetailsP&W · T400-CP-400 · Turboshaft · 900
Seats2
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 39 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility50 sm
CeilingNone
Temperature / Dew Point0 C
Altimeter0
Weather SourcePILO