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NTSB Report
June 6, 1987 · Bell 206L-1 · N4999N
Choteau, MT
Overview
Report Status
Preliminary report
Event Type
Accident
Date
June 6, 1987
Injury Outcomes
4 injuries (4 fatalities)
Location
Choteau, MT
Aircraft
Bell 206L-1
Tail Number
N4999N
Operator
Minuteman Aviation
Injuries
Fatal
Aircraft Damage
Destroyed
NTSB Number
DEN87FA147
THE EMS HELICOPTER WAS RETURNING TO GREAT FALLS, MT, ON 6/5/87 WHEN IT CRASHED. ITS OCCUPANTS HAD EARLIER PARTICIPATED IN A RESCUE SEMINAR AT MANY GLACIER, MT. THE WRECKAGE WAS NOT FOUND UNTIL 6/9/87. A VIDEO TAPE RECOVERED FROM THE WRECKAGE DISCLOSED THE HELICOPTER TO BE FOLLOWING A HERD OF BIG HORN SHEEP UP A 7000-FT MOUNTAIN SLOPE AND FLYING SLOWLY AT TREE-TOP LEVEL WHEN IT SUDDENLY YAWED TO THE RIGHT. TESTS MADE ON THE AUDIO PORTION OF THE VIDEO TAPE REVEALED MAIN/TAIL ROTOR RPM WAS AT 100% POWER UNTIL 3.5 SEC BEFORE END OF TAPE. AT THAT TIME MAIN/TAIL ROTOR RPM DROPPED TO 94%. EVIDENCE ALSO DISCLOSED HELICOPTER TO BE FLYING AT HIGH GROSS WEIGHT, HIGH DENSITY ALTITUDE, AND WITH A TAILWIND.
Full Narrative
THE EMS HELICOPTER WAS RETURNING TO GREAT FALLS, MT, ON 6/5/87 WHEN IT CRASHED. ITS OCCUPANTS HAD EARLIER PARTICIPATED IN A RESCUE SEMINAR AT MANY GLACIER, MT. THE WRECKAGE WAS NOT FOUND UNTIL 6/9/87. A VIDEO TAPE RECOVERED FROM THE WRECKAGE DISCLOSED THE HELICOPTER TO BE FOLLOWING A HERD OF BIG HORN SHEEP UP A 7000-FT MOUNTAIN SLOPE AND FLYING SLOWLY AT TREE-TOP LEVEL WHEN IT SUDDENLY YAWED TO THE RIGHT. TESTS MADE ON THE AUDIO PORTION OF THE VIDEO TAPE REVEALED MAIN/TAIL ROTOR RPM WAS AT 100% POWER UNTIL 3.5 SEC BEFORE END OF TAPE. AT THAT TIME MAIN/TAIL ROTOR RPM DROPPED TO 94%. EVIDENCE ALSO DISCLOSED HELICOPTER TO BE FLYING AT HIGH GROSS WEIGHT, HIGH DENSITY ALTITUDE, AND WITH A TAILWIND.
Flight
Event TypeAccident
Event Time20:15 MDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireGrd
Aircraft ExplosionNo
Aircraft
AircraftBell 206L-1
Tail NumberN4999N
Aircraft CategoryHeli
DamageDestroyed
OperatorMinuteman Aviation
Operating RulePart 135
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250-C28B · Turboshaft · 435
Seats4
People & Injuries
Injury Summary4 injuries (4 fatalities)
Fatal4
Serious0
Minor0
Uninjured0
Total4
Crew 1Age 43 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind180° @ 16 kt, gusting 24 kt
Visibility40 sm
CeilingBroken clouds 14000 ft
Temperature / Dew Point46
Altimeter29.00 inHg
Observation Time01:50
Weather SourceWFAC