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NTSB Report
May 23, 1990 · Hughes 269A · N8793F
La Verne, CA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
May 23, 1990
Injury Outcomes
2 injuries (2 minor injuries)
Location
La Verne, CA
Aircraft
Hughes 269A
Tail Number
N8793F
Operator
Randy Polous
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
LAX90LA186
THE PILOT HAD BEEN ASKED BY THE OPERATOR TO FLY THE HELICOPTER PRIOR TO THE OPERATORS SIGNING A LEASEBACK AGREEMENT WITH THE REPORTED OWNER. THE INITIAL AIR TAXI TO A HELIPAD WAS ABORTED WHEN THE HELICOPTER BEGAN TO OSCILLATE DURING A GROUND RESONANCE EVENT. PRIOR TO THIS ATTEMPT THE OLEO STRUTS APPEARED TO BE OF EQUAL EXTENSION. AFTER THE EVENT, THE OLEO STRUTS WERE LOW AND ONE WAS FLAT. ABOUT 18 DAYS LATER, AND AFTER THE PILOT HAD BEEN TOLD THAT THE STRUTS HAD BEEN TAKEN CARE OF AND THAT THE OWNER HAD BEEN FLYING THE HELICOPTER AFTER A PLANNED AIR TAXI TO A HELIPAD. THE HELICOPTER AGAIN EXPERIENCED A GROUND RESONANCE EVENT WITH SEVERE OSCILLATIONS TO THE POINT OF DESTRUCTION. THE PILOT SAID HE LOWERED THE COLLECTIVE AND DECREASED THE THROTTLE WHEN THE OSCILLATIONS BEGAN. ATTEMPTS TO OBTAIN THE MAINTENANCE RECORDS AND COMPONENTS OF THE HELICOPTER FOR TESTING WERE UNSUCCESSFUL.
NTSB Probable Cause
GROUND RESONANCE DUE TO AN INADEQUATELY MAINTAINED STRUT.
Full Narrative
THE PILOT HAD BEEN ASKED BY THE OPERATOR TO FLY THE HELICOPTER PRIOR TO THE OPERATORS SIGNING A LEASEBACK AGREEMENT WITH THE REPORTED OWNER. THE INITIAL AIR TAXI TO A HELIPAD WAS ABORTED WHEN THE HELICOPTER BEGAN TO OSCILLATE DURING A GROUND RESONANCE EVENT. PRIOR TO THIS ATTEMPT THE OLEO STRUTS APPEARED TO BE OF EQUAL EXTENSION. AFTER THE EVENT, THE OLEO STRUTS WERE LOW AND ONE WAS FLAT. ABOUT 18 DAYS LATER, AND AFTER THE PILOT HAD BEEN TOLD THAT THE STRUTS HAD BEEN TAKEN CARE OF AND THAT THE OWNER HAD BEEN FLYING THE HELICOPTER AFTER A PLANNED AIR TAXI TO A HELIPAD. THE HELICOPTER AGAIN EXPERIENCED A GROUND RESONANCE EVENT WITH SEVERE OSCILLATIONS TO THE POINT OF DESTRUCTION. THE PILOT SAID HE LOWERED THE COLLECTIVE AND DECREASED THE THROTTLE WHEN THE OSCILLATIONS BEGAN. ATTEMPTS TO OBTAIN THE MAINTENANCE RECORDS AND COMPONENTS OF THE HELICOPTER FOR TESTING WERE UNSUCCESSFUL.
Flight
Event TypeAccident
Event Time09:20 PDT
Nearest AirportBrackett Field (0nm)
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftHughes 269A
Tail NumberN8793F
Aircraft CategoryHeli
DamageSubstantial
OperatorRandy Polous
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · IO-360 · Reciprocating · 180
Seats2
People & Injuries
Injury Summary2 injuries (2 minor injuries)
Fatal0
Serious0
Minor2
Uninjured0
Total2
Crew 1Age 29 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility10 sm
CeilingNone
Temperature / Dew Point64 F / 0 C
Altimeter0
Weather SourcePILO