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NTSB Report
September 2, 1990 · Bell 47G-3B1 · N73957
Canon City, CO
Overview
Report Status
Probable Cause
Event Type
Accident
Date
September 2, 1990
Injury Outcomes
1 injury (1 minor injury)
Location
Canon City, CO
Aircraft
Bell 47G-3B1
Tail Number
N73957
Operator
Cherokee Helicopter Service
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
DEN90LA180
THE HELICOPTER COLLIDED WITH POWER LINES WHILE ON A DOWNWIND TO THE HELIPAD. ACCORDING TO WITNESSES, THE HELICOPTER WAS TRAVELLING PERPENDICULAR TO AN ELECTRICAL TRANSMISSION LINE AT ABOUT 60 KNOTS WHEN IT COLLIDED WITH THE TOP OF A TWO WIRE SET AT ABOUT 30 FEET AGL. PAINT TRANSFER FROM THE T/R SKID WAS FOUND ON THE DAMAGED POWER LINE. AFTER STRIKING THE WIRE THE T/R SEPARATED AT THE GEAR BOX MOUNTING FLANGE; SMALL PIECES OF THE T/R BLADE WERE FOUND ON THE GROUND BELOW THE POINT OF INITIAL WIRE CONTACT. THE PILOT STATED THAT DURING THE DOWNWIND CLIMBING TURN AFTER TAKEOFF, AND WHILE PASSING OVER A GULLY NEAR A 6,200-FT RIDGE, HE HAD AN ENCOUNTER WITH WINDSHEAR AT 230 FEET AGL WHICH RESULTED IN LOSS OF 200 FEET AND THE SUBSEQUENT COLLISION. THE EXISTENCE OF THE REPORTED 'WINDSHEAR', OR POSSIBLE DOWNDRAFT COULD NOT BE VERIFIED.
NTSB Probable Cause
THE PILOT'S FAILURE TO MAINTAIN AN ADEQUATE PATTERN ALTITUDE AND THE POSSIBLE EXISTENCE OF ADVERSE WINDS DUE TO THE SURROUNDING TERRAIN.
Full Narrative
THE HELICOPTER COLLIDED WITH POWER LINES WHILE ON A DOWNWIND TO THE HELIPAD. ACCORDING TO WITNESSES, THE HELICOPTER WAS TRAVELLING PERPENDICULAR TO AN ELECTRICAL TRANSMISSION LINE AT ABOUT 60 KNOTS WHEN IT COLLIDED WITH THE TOP OF A TWO WIRE SET AT ABOUT 30 FEET AGL. PAINT TRANSFER FROM THE T/R SKID WAS FOUND ON THE DAMAGED POWER LINE. AFTER STRIKING THE WIRE THE T/R SEPARATED AT THE GEAR BOX MOUNTING FLANGE; SMALL PIECES OF THE T/R BLADE WERE FOUND ON THE GROUND BELOW THE POINT OF INITIAL WIRE CONTACT. THE PILOT STATED THAT DURING THE DOWNWIND CLIMBING TURN AFTER TAKEOFF, AND WHILE PASSING OVER A GULLY NEAR A 6,200-FT RIDGE, HE HAD AN ENCOUNTER WITH WINDSHEAR AT 230 FEET AGL WHICH RESULTED IN LOSS OF 200 FEET AND THE SUBSEQUENT COLLISION. THE EXISTENCE OF THE REPORTED 'WINDSHEAR', OR POSSIBLE DOWNDRAFT COULD NOT BE VERIFIED.
Flight
Event TypeAccident
Event Time12:35 MDT
Nearest AirportBrown'S Fort Helipad (0nm N)
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47G-3B1
Tail NumberN73957
Aircraft CategoryHeli
DamageSubstantial
OperatorCherokee Helicopter Service
Operating RulePart 91
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250C20B · Turboshaft
Seats3
People & Injuries
Injury Summary1 injury (1 minor injury)
Fatal0
Serious0
Minor1
Uninjured0
Total1
Crew 1Age 28 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind60° @ 10 kt, gusting 6 kt
Visibility15 sm
CeilingNone
Temperature / Dew Point55
Altimeter0
Observation Time17:50
Weather SourceWFAC