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NTSB Report
May 11, 1990 · Hughes 369E · N5217N
Firebaugh, CA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
May 11, 1990
Injury Outcomes
No injuries (1 uninjured)
Location
Firebaugh, CA
Aircraft
Hughes 369E
Tail Number
N5217N
Injuries
None
Aircraft Damage
Substantial
NTSB Number
LAX90LA171
THE HELICOPTER LOST ENG POWER AND LANDED HARD. THE PLT REPORTED HE HAD JUST COMPLETED RELEASING AN EXTERNAL LOAD. THE HELICOPTER WAS ABOUT 125 FEET AGL IN A CLIMBING LEFT TURN WHEN THE PLT HEARD A LOUD BANG. THE PLT ENTERED AUTOROTATION. THE PLT NOTED THAT THE MAIN ROTOR RPM WAS LOW AND WAS UNABLE TO REGAIN ANY MAIN ROTOR RPM BEFORE THE LANDING FLAIR. AT TOUCHDOWN, THE MAIN ROTOR BLADES FLEXED DOWNWARD AND SEVERED THE TAILBOOM. THE THIRD STAGE COMPRESSOR HAD FAILED, DAMAGING THE REMAINING STAGES OF THE COMPRESSOR. THE COMPRESSOR CASE PLASTIC WAS ERODED. THE ENG HAD UNDERGONE MAJOR MAINTENANCE AT 1,774.5 HOURS WHICH REQUIRED THE REMOVAL OF THE TURBINE SECTION. THERE WAS NO EVIDENCE IN THE ENG LOGBOOKS OF THE COMPRESSOR SECTION BEING INSPECTED AT 1,750 HOURS AS REQUIRED BY THE MANUFACTURER. THE ENGINE MAINTENANCE MANUAL WARNS EROSION WILL CAUSE DAMAGE TO COMPRESSOR BLADES AND VANES.
NTSB Probable Cause
FAILURE BY COMPANY MAINTENANCE TO PERFORM A MANDATORY COMPRESSOR SECTION INSPECTION THAT RESULTED IN THE UNDETECTED EROSION OF THE COMPRESSOR VANES AND ENGINE FAILURE. CONTRIBUTING TO THE ACCIDENT WAS THE FAILURE OF THE PILOT TO MAINTAIN ADEQUATE MAIN ROTOR RPM AT CRITICAL ALTITUDE.
Full Narrative
THE HELICOPTER LOST ENG POWER AND LANDED HARD. THE PLT REPORTED HE HAD JUST COMPLETED RELEASING AN EXTERNAL LOAD. THE HELICOPTER WAS ABOUT 125 FEET AGL IN A CLIMBING LEFT TURN WHEN THE PLT HEARD A LOUD BANG. THE PLT ENTERED AUTOROTATION. THE PLT NOTED THAT THE MAIN ROTOR RPM WAS LOW AND WAS UNABLE TO REGAIN ANY MAIN ROTOR RPM BEFORE THE LANDING FLAIR. AT TOUCHDOWN, THE MAIN ROTOR BLADES FLEXED DOWNWARD AND SEVERED THE TAILBOOM. THE THIRD STAGE COMPRESSOR HAD FAILED, DAMAGING THE REMAINING STAGES OF THE COMPRESSOR. THE COMPRESSOR CASE PLASTIC WAS ERODED. THE ENG HAD UNDERGONE MAJOR MAINTENANCE AT 1,774.5 HOURS WHICH REQUIRED THE REMOVAL OF THE TURBINE SECTION. THERE WAS NO EVIDENCE IN THE ENG LOGBOOKS OF THE COMPRESSOR SECTION BEING INSPECTED AT 1,750 HOURS AS REQUIRED BY THE MANUFACTURER. THE ENGINE MAINTENANCE MANUAL WARNS EROSION WILL CAUSE DAMAGE TO COMPRESSOR BLADES AND VANES.
Flight
Event TypeAccident
Event Time18:00 PDT
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftHughes 369E
Tail NumberN5217N
Aircraft CategoryHeli
DamageSubstantial
Operating RulePart 133
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250 C20B · Turboshaft · 420
Seats5
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 55 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind290° @ 4 kt
Visibility10 sm
CeilingNone
Temperature / Dew Point70 F / 46
Altimeter29.00 inHg
Observation Time00:50
Weather SourceWFAC