SEA95FA214 · Agusta A109A II
Hospital Air Transport Agusta A109A II · Accident: in flight collision with terrain/water en route
From King County International Airport - Boeing Field (BFI) to WA
Event
- NTSB case
- SEA95FA214
- 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
- 3 · 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
- Unknown
Agusta A109A II
- Aircraft type
- Agusta A109
- 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
- N1WC
- Operator
- Hospital Air Transport
- Onboard fatalities
- Unknown
- Route
- From King County International Airport - Boeing Field (BFI), Seattle, WATo WA
- 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/clearance, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter pilot took off at night on a positioning flight for an emergency medical service (EMS) operation. There were reports of a low overcast layer varying from 1,000 feet above ground level to the surface. The majority of the witnesses reported that the helicopter was flying low as it traveled over the ground and continued over water toward a nearby island. Subsequently, the helicopter collided with the water and sank. Several of the witnesses reported that the engine sounded normal until the helicopter crashed. Some witnesses reported a 'popping' sound or a 'laboring' sound from the engines; however, after the engines were recovered at a later date, no evidence of a preimpact mechanical failure or malfunction was found. Local residents reported that the water condition at the time of the accident was 'calm' or 'glassy.' Several small pieces of the fuselage and main rotor blades were found floating on the surface of the water. Examination revealed that 3 of the main rotor blades had separated approximately three feet out from the attach points. The fourth blade separated approximately seven feet out from the attach point; however, the blade was bent and cracked chordwise approximately three feet out from the attach point. Using side scan sonar, wreckage was found over a distance of approximately 600 feet. The landing gear was found in the extended position, and the engine power levers were found in the flight position. Also, torsional evidence was found on the tail rotor driveshaft.
Probable cause
the pilot failed to maintain sufficient altitude/clearance above the surface of water, while flying over calm water conditions at night. Factors relating to the accident were: darkness, low ceiling, fog, glassy (calm) water conditions, and the lack of visual cues for visual perception of altitude.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA95FA214
- Event ID
- 20001207X04591
- Case number
- SEA95FA214
- 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. 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: 3a382cffb59233ad38e5e078d8898bf841f39f5bc8c141253087b6017efe6dfa; retrieved 2026-09-20T23:37:30.287Z.