IAD04IA032 · Aviat A-1A
Aviat A-1A · Incident: partial loss of engine power (non-mechanical) en route
From Laconia Municipal Airport (LCI) to an unrecorded destination
Event
- NTSB case
- IAD04IA032
- 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
- Incident
- 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
Aviat A-1A
- Aircraft type
- Aviat A-1
- 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
- N4674L
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Laconia Municipal Airport (LCI), Laconia, NHTo 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 (non-mechanical)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Pilot in command › Carburetor heat, improper use of
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
According to the pilot, while cruising at 700-800 feet agl, the airplane's engine began running roughly, and experienced a loss of power. The pilot enriched the mixture, then applied carburetor heat, which made the engine run rougher, so he removed it. The engine continued to lose power until level flight could no longer be maintained. The pilot opted to land in a farmer's field; however, irrigation equipment was present, so he landed on a beach along a river. The airplane touched down fast, and subsequently floated. Nearing the end of the beach, the pilot attempted to abort the landing. When the pilot advanced the throttle, the engine responded with "about 15 percent power." The wheels of the airplane contacted the water, and the airplane nosed over, and came to rest upside down in the river. Prior to the incident, the pilot had contacted the state division of aeronautics regarding the legality of landing on sandbars in that river. Ambient temperature/dewpoint conditions at the time were favorable for moderate carburetor icing at cruise power, and serious carburetor icing at glide power.
Probable cause
The pilot's improper use of carburetor heat, which resulted in a loss of engine power. A factor was the lack of suitable terrain for the forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record IAD04IA032
- Event ID
- 20040729X01102
- Case number
- IAD04IA032
- 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: 5bbb7488ca1b4c09ca6821ab0b72011c6cbee6cb7283295056732fdcdd8587c2; retrieved 2026-09-22T07:04:49.283Z.