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NTSB Report
January 27, 1991 · Mbb BK 117 B-1 · N891GM
Sonestown, PA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
January 27, 1991
Injury Outcomes
4 injuries (4 fatalities)
Location
Sonestown, PA
Aircraft
Mbb BK 117 B-1
Tail Number
N891GM
Operator
Keystone Helicopter Corporatio
Injuries
Fatal
Aircraft Damage
Destroyed
NTSB Number
NYC91FA067
THE MEDIVAC HELICOPTER WAS RETURNING TO SAYRE AFTER TRANSPORTING A PATIENT TO DANVILLE. RECORDED RADAR DATA AND DATA OBTAINED FROM THE HELICOPTER'S LORAN-C MEMORY INDICATES THAT THE FLIGHT WAS FOLLOWING A DIRECT COURSE FROM THE GEISINGER MEDICAL CENTER AT DANVILLE TO THE ROBERT PACKER HOSPITAL AT SAYRE. THE ACFT'S HSI WAS SET TO DISPLAY LORAN COURSE INFORMATION. THE CLOSEST POINT OF THE COURSE TO THE CREST OF NORTH MOUNTAIN WAS APRX 3/4 MILE TO THE WEST. THE PILOT HAD ADVISED WILLIAMSPORT ATCT TRANSITTING THEIR CONTROL ZONE AT 2,500 FT. IMPACT OCCURRED AT 2,440 FT MSL. THE CREST OF THE RIDGE IS 2,520 FT MSL WITH 40-FT HIGH TREES. A WITNESS WHO LIVES IN A CABIN ON THE MOUNTAIN 200 YARDS FROM THE ACCIDENT SITE STATED THAT IT WAS SNOWING VERY HARD WHEN HE ARRIVED AT THE CABIN AROUND 1930.
NTSB Probable Cause
THE PILOT'S INADEQUATE PREFLIGHT PLANNING TO ASSURE THAT THE INTENDED COURSE AND ALTITUDE PROVIDED ADEQUATE TERRAIN CLEARANCE. CONTRIBUTING FACTOR(S) WAS: THE DARK NIGHT, SNOW AND MOUNTAINOUS TERRAIN.
Full Narrative
THE MEDIVAC HELICOPTER WAS RETURNING TO SAYRE AFTER TRANSPORTING A PATIENT TO DANVILLE. RECORDED RADAR DATA AND DATA OBTAINED FROM THE HELICOPTER'S LORAN-C MEMORY INDICATES THAT THE FLIGHT WAS FOLLOWING A DIRECT COURSE FROM THE GEISINGER MEDICAL CENTER AT DANVILLE TO THE ROBERT PACKER HOSPITAL AT SAYRE. THE ACFT'S HSI WAS SET TO DISPLAY LORAN COURSE INFORMATION. THE CLOSEST POINT OF THE COURSE TO THE CREST OF NORTH MOUNTAIN WAS APRX 3/4 MILE TO THE WEST. THE PILOT HAD ADVISED WILLIAMSPORT ATCT TRANSITTING THEIR CONTROL ZONE AT 2,500 FT. IMPACT OCCURRED AT 2,440 FT MSL. THE CREST OF THE RIDGE IS 2,520 FT MSL WITH 40-FT HIGH TREES. A WITNESS WHO LIVES IN A CABIN ON THE MOUNTAIN 200 YARDS FROM THE ACCIDENT SITE STATED THAT IT WAS SNOWING VERY HARD WHEN HE ARRIVED AT THE CABIN AROUND 1930.
Flight
Event TypeAccident
Event Time19:48 EST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledCvfr
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftMbb BK 117 B-1
Tail NumberN891GM
Aircraft CategoryHeli
DamageDestroyed
OperatorKeystone Helicopter Corporatio
Operating RulePart 91
Engines2
Engine TypeTurboshaft
Engine DetailsLycoming · LTS101-650B-1 · Turboshaft · 650
Seats5
People & Injuries
Injury Summary4 injuries (4 fatalities)
Fatal4
Serious0
Minor0
Uninjured0
Total4
Crew 1Age 35 · First Class
Conditions
ConditionsIMC
LightDark Night
WindCalm
CeilingNone
Temperature / Dew Point0 C / 0 C
Altimeter0
Weather SourceWIT