NYC91FA067 · MBB BK 117 B-1
Keystone Helicopter Corporatio MBB BK 117 B-1 · Accident: in flight collision with terrain/water en route
From Danville, PA to Sayre, PA
Event
- NTSB case
- NYC91FA067
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 4 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
MBB BK 117 B-1
- Aircraft type
- MBB BK-117
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N891GM
- Operator
- Keystone Helicopter Corporatio
- Onboard fatalities
- Unknown
- Route
- From Danville, PATo Sayre, PA
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- In flight collision with terrain/water
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Altitude, inadequate
- Pilot in command › Preflight planning/preparation, inadequate
Not plotted · Location withheld: coordinates are missing, conflicting, invalid, or have no accepted acquisition method. No substitute location has been invented.
NTSB 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.
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC91FA067
- Event ID
- 20001212X16367
- Case number
- NYC91FA067
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1991-01-27.
- API snapshot SHA-256: 4a749d54c71c94b3e177b0383faaf8eca4008b4488f507cb5bba2f4b8f1e1e5b; retrieved 2026-09-21T01:59:40.699Z.