Messerschmitt-Bolkow-Blohm BK 117 accident near Hamburg, New York, May 4, 2014
On May 4, 2014 at about 9:40 pm local time, a 1971 Messerschmitt-Bolkow-Blohm BK 117 (helicopter), registered N504TJ, was substantially damaged in an accident during enroute (cruise) near Hamburg, New York. It was a positioning flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Wear in the left cabin door assembly parts, which resulted in the door partially opening in flight, dislodging from the lower door track assembly, and then separating from the helicopter.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 4, 2014 · about 9:40 pm local time
- Place
- Hamburg, New York · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Messerschmitt-Bolkow-Blohm BK 117 A-4, built 1971 · all BK 117s on the register
- Registration
- N504TJ · no longer on the register · serial 7138
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, during a repositioning flight of the emergency medical services helicopter and while at cruise altitude, the flight nurse notified him and the paramedic that the left cabin door had partially opened. As the flight nurse and paramedic were attempting to close the door, it dislodged from the lower track assembly, pivoted up, and struck the main rotor system; the door subsequently separated from the helicopter. The pilot then initiated a forced landing to a field. Examination of the door assembly revealed that both of the lower door's bracket guides and the aft lower catcher and guide assemblies were worn and that the door's upper sliders were worn down to their minimum tolerances. The Airplane Maintenance Manual states that, if one of the two sliders does not meet the minimum tolerance, "both sliders must be replaced with new ones." A review of the maintenance logbook revealed that the door assembly had been inspected 127 hours before the accident in accordance with an alert service bulletin but that no anomalies with the door assembly were noted at that time.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Aircraft maintenance event during prior to flight
- Part(s) separation from AC during enroute (cruise) defining event
- Off-field or emergency landing during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft structures › Doors › Passenger/crew doors › Fatigue/wear/corrosion
- cause Aircraft › Aircraft structures › Doors › Passenger/crew doors › Incorrect service/maintenance
- cause Aircraft › Aircraft structures › Doors › Passenger/crew doors › Failure
- cause Personnel issues › Task performance › Inspection › Scheduled/routine inspection › Maintenance personnel
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,310 hours in all; 365 in this make and model; 32 in the last 90 days; 12 in the last 30 days; 3,260 as pilot in command
- Last flight review: April 21, 2014
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 11,735 hours
- Last inspection: 100-hour inspection, April 14, 2014
- Maximum gross weight: 7,055 lb
- Seats: 6
- Landing gear: fixed
- Engine 1: Honeywell LTS-101-650B1 (turboshaft); 5,500 hours total
- Engine 2: Honeywell LTS-101-650B1 (turboshaft); 11,558 hours total
- Operator: Mercy Flight INC
The flight
- Departed from: 7NK9 Buffalo NY at 9:30 pm
- Destination: 5NK4 Olean NY
Weather at the time
- Light: daylight
- Wind: from 340° at 10 knots
- Visibility: 10 statute miles
- Sky: overcast at 4,200 ft; ovct at 4,200 ft
- Temperature: 50°F (10°C), dew point 37°F (3°C)
- Altimeter: 29.84 inHg
- Observation at 9:54 pm from BUF, 15 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.