NYC03LA033 · MBB BK 117 A-4
MBB BK 117 A-4 · Accident: on ground/water encounter with weather while standing
From Albany Medical Center Heliport (NK64) to an unrecorded destination
Event
- NTSB case
- NYC03LA033
- 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
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- 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
- Visual Meteorological Cond
MBB BK 117 A-4
- 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
- N951AM
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Albany Medical Center Heliport (NK64), Albany, NYTo not recorded
- 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
- Standing · engine(s) start-up
- 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
- On ground/water encounter with weather
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Weather condition › Downdraft
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter was positioned on the hospital rooftop helipad facing in a southerly direction. After the medical crew boarded the helicopter, the number 1 engine was started. As the main rotor blades began to turn, an unexpected gust of wind traveling over the rooftop caused the blades to flap excessively. The pilot then heard a series of thumps, and aborted the start. Inspection of the helicopter revealed that one of the main rotor blades had come in contact with the left vertical stabilizer, damaging the tail boom, main rotor blades, and the left vertical stabilizer. On November 30, 1990, the helicopter manufacturer issued service bulletin SB-MBB-BK-30-103, which called for a triangle section to be cut out of the stabilizer fin assembly, in an area where a potential strike from a main rotor blade could occur, and replaced with a foam core insert. The operator did not apply the service bulletin to the accident helicopter. The winds reported by the pilot at the time of the engine start were from 340 degrees at 14 knots, gusting to 24 knots.
Probable cause
The inadvertent encounter with a downdraft during engine start, which flexed the main rotor blades and subsequently damaged the tail boom assembly. A factor related to the accident was the failure of the operator to comply with a service bulletin.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC03LA033
- Event ID
- 20030102X00001
- Case number
- NYC03LA033
- 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: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: d3f5fcb927349f5534bb443435cf140b1c06651ac7864fcfcedb1a215b1d52ae; retrieved 2026-09-22T09:46:44.262Z.