MBB BK 117 B-1 N891GM

Summary

On 27 January 1991 at about 00:48 local time, a MBB BK 117 B-1 registered N891GM, operated by Keystone Helicopter Corporatio, was involved in an accident near Sonestown, Pennsylvania, United States. 4 people were on board and 4 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

27 January 1991 at 00:48

Classification

Accident

Location

Sonestown, Pennsylvania, United States

Coordinates

Not recorded

Aircraft

MBB BK 117 B-1

Registration

N891GM

Category

Helicopter

Engines

2

Operator

Keystone Helicopter Corporatio

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Danville → Sayre

Aircraft damage

Destroyed

Weather

IMC

Light

Night/Dark

NTSB number

NYC91FA067

4 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.