BFO94LA010 · Gulfstream American AA-5B
Gulfstream American AA-5B · Accident: partial loss of engine power (mechanical failure) en route
From Minute Man Air Field (6B6) to an unrecorded destination
Event
- NTSB case
- BFO94LA010
- 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
- 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
- Visual Meteorological Cond
Gulfstream American AA-5B
- Aircraft type
- Gulfstream American AA-5
- Category
- Airplane
- 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
- N28215
- Operator
- James Connelly
- Onboard fatalities
- Unknown
- Route
- From Minute Man Air Field (6B6), Stow, MATo 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
- 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
- Partial loss of engine power (mechanical failure)
- 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
- Engine assembly, valve, exhaust › Fatigue
Approximate · Estimated position: the centre of Sterling, MA, the place the record names. Not the accident site.
NTSB narrative
THE PILOT REPORTED THAT THE AIRPLANE WAS AT 2000 FEET MSL WHEN A SEVERE VIBRATION DEVELOPED ON THE AIRPLANE. HE STATED THAT THE AIRPLANE WAS DESCENDING AT 200 FEET PER MINUTE WITH THE THROTTLE FULL FORWARD, AND 1700 RPM ON HIS GAGE. HE STATED THAT THE NEAREST AIRPORT WAS ABOUT 6 MILES AWAY, SO HE RADIOED THE AIRPORT OF HIS SITUATION AND ENTERED THE TRAFFIC PATTERN ON THE BASE LEG. HE STATED THAT HE WAS HIGH ON THE APPROACH, BUT HE RECALLED FROM HIS TRAINING THAT IT WAS BETTER TO BE HIGH AND FAST THAN LOW AND SLOW. THE AIRPLANE TOUCHED DOWN ABOUT HALF WAY DOWN THE 3100 FOOT LONG RUNWAY AND EXITED INTO A SIX FOOT CULVERT WHERE IT NOSED OVER. AN EXAMINATION OF THE ENGINE BY THE FAA REVEALED A LEAK WHEN A COMPRESSION TEST WAS COMPLETED. THE CYLINDER WAS REMOVED AND SENT TO THE NTSB LAB IN WASHINGTON, DC. A METALLURGICAL EXAMINATION REVEALED THE EXHAUST VALVE SEPARATED AS A RESULT OF FATIGUE CRACKING THAT INITIATED IN THE RADIUS BETWEEN THE STEM AND THE HEAD OF THE VALVE.
Probable cause
SEPARATION OF THE NUMBER ONE EXHAUST VALVE DUE TO FATIGUE CRACKING WHICH RESULTED IN LOSS OF ENGINE POWER. OTHER RELATED FACTORS WERE MISJUDGMENT OF ALTITUDE AND AIRSPEED BY THE PILOT RESULTING IN ON GROUND COLLISION WITH THE TERRAIN AND SUBSEQUENT NOSE OVER.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record BFO94LA010
- Event ID
- 20001211X13703
- Case number
- BFO94LA010
- 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: c9074d4f3906e1ae7dd105ed5b2ca83b2de2280300e50b29858b7fabf54413d7; retrieved 2026-09-21T22:45:38.233Z.