ERA09LA399 · Cessna 172N
New England Flight Operations Cessna 172N · Accident: powerplant system/component malfunction/failure en route
From Nashua Airport / Boire Field (ASH) to Martha's Vineyard Airport (MVY)
Event
- NTSB case
- ERA09LA399
- 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
Cessna 172N
- Aircraft type
- Cessna 172
- 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
- N4773G
- Operator
- New England Flight Operations
- Onboard fatalities
- Unknown
- Route
- From Nashua Airport / Boire Field (ASH), Nashua, NHTo Martha's Vineyard Airport (MVY), Vineyard Haven, MA
- 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
- Defining eventThe 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
- Powerplant system/component malfunction/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
- Not determined › Not determined
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the airplane was in cruise flight when the engine developed sporadic engine vibrations. Manipulation of the carburetor heat and mixture controls did not remedy the situation and the engine subsequently developed a severe vibration. The pilot then elected to reduce engine power and perform a precautionary landing to a field. The airplane touched down in a cranberry bog, and sustained substantial firewall and airframe damage. Examination of the wreckage did not reveal any mechanical malfunctions. It was noted that the No. 2 cylinder lower spark plug was fouled and that the compression on the No. 4 cylinder was lower than that of cylinders 1, 2 and 3; however, the reason for the severe engine vibration could not be determined. The airplane had been operated for approximately 74 hours since its most recent 100 hour inspection, which was performed about two months prior to the accident.
Probable cause
An engine vibration as reported by the pilot, for undetermined reasons.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA09LA399
- Event ID
- 20090712X04733
- Case number
- ERA09LA399
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: d055c589a75314a1af4e1c868a75a55b5fe1b9a579b7f17b00b1debe5b9d4c7f; retrieved 2026-09-15T11:47:39.126Z.