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NTSB Report
May 18, 1994 · Bell 47G · N933B
Sulphur, OK
Overview
Report Status
Final with probable cause
Event Type
Accident
Date
May 18, 1994
Injury Outcomes
No injuries (1 uninjured)
Location
Sulphur, OK
Aircraft
Bell 47G
Tail Number
N933B
Injuries
None
Aircraft Damage
Substantial
NTSB Number
FTW94LA166
A TOTAL LOSS OF ENGINE POWER OCCURRED AT 50 FEET ABOVE THE GROUND DURING THE INITIAL PHASE OF A TURN-AROUND MANEUVER. TREES HINDERED THE PILOT'S COMPLETION OF THE AUTOROTATION. THE HELICOPTER BOUNCED DURING THE LANDING AND THE MAIN ROTOR BLADE FLEXED AND SEVERED THE TAILBOOM. AN EXAMINATION OF THE ENGINE BY THE OPERATOR REVEALED THE FAILURE OF AN ENGINE ACCESSORY OIL PUMP GEAR.
NTSB Probable Cause
THE LOSS OF ENGINE POWER DUE TO THE FAILURE OF AN ENGINE ACCESSORY OIL PUMP GEAR. A FACTOR WAS THE LACK OF SUITABLE TERRAIN FOR THE AUTOROTATION.
Full Narrative
On May 18, 1994, at 1830 central daylight time, a Bell 47G, N933B, sustained substantial damage during a forced landing near Sulphur, Oklahoma. The commercial pilot did not receive injuries. Visual meteorological conditions prevailed for the local aerial application flight. The pilot reported a total loss of engine power at 50 feet above the ground during the initial phase of a turn-around maneuver. He further said that trees in the area and the height of the helicopter hindered his completion of a successful autorotation. The helicopter bounced during the hard landing and the main rotor blade flexed and severed the tailboom. During a telephone interview the operator reported the total loss of engine power was due to the failure of the oil pump drive gear in the accessory case.
Flight
Event TypeAccident
Event Time18:30 CDT
Nearest Airport0nm
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47G
Tail NumberN933B
Aircraft CategoryHeli
DamageSubstantial
Operating RulePart 137
Engines1
Engine TypeReciprocating
Engine DetailsFranklin · 6V-335-A · Reciprocating · 210
Seats2
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 27 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind60° @ 3 kt
Visibility10 sm
CeilingNone
Temperature / Dew Point0 C / 0 C
Altimeter0
Weather SourcePILO