ERA17LA275 · Piper J3C 65
Berkshire Aviation Enterprises Piper J3C 65 · Accident: powerplant system/component malfunction/failure en route
From Walter J. Koladza Airport (GBR) to Walter J. Koladza Airport (GBR)
Event
- NTSB case
- ERA17LA275
- 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
Piper J3C 65
- Aircraft type
- Piper J3
- 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
- N98550
- Operator
- Berkshire Aviation Enterprises
- Onboard fatalities
- Unknown
- Route
- From Walter J. Koladza Airport (GBR), Great Barrington, MATo Walter J. Koladza Airport (GBR), Great Barrington, MA
- Aircraft age
- About 71 years (built 1946)
- 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
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- 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
- Aircraft › Aircraft power plant
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During cruise flight, the airplane experienced a total loss of engine power, and the flight instructor performed a forced landing into trees. The engine crankshaft was replaced about 4 years and about 317 hours of operation before the accident. Teardown examination of the engine revealed that the crankshaft gear screws were fractured, and the crankshaft gear was separated from the crankshaft. Fretting was observed near two of the four crankshaft screw holes and corresponded to two elongated screw holes on the crankshaft gear. The crankshaft and crankshaft gear did not contain a dowel pin as specified in the most current versions of the manufacturer's illustrated parts catalog and overhaul manual, which were published more than 2 years before the crankshaft replacement. Additionally, the crankshaft gear did not contain a dowel pin hole, which was consistent with a crankshaft gear for an older, different model engine. Both publications contained numerous instructions and references to use a crankshaft gear with a dowel pin hole and to align the gear to the crankshaft with a dowel pin, which would pilot the crankshaft gear on the crankshaft. Thus, it is likely that when the crankshaft was replaced, maintenance personnel did not use the most recent manuals and installed a crankshaft gear for a different engine, which led to the crankshaft gear's failure and the subsequent loss of all engine power.
Probable cause
An improper replacement of the crankshaft by maintenance personnel, which resulted in a failure of the crankshaft gear and total loss of engine power.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA17LA275
- Event ID
- 20170813X83417
- Case number
- ERA17LA275
- 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: 2e446fd1ad15acea275be34da80a5dcb3801b1c729c56ddf7159c15886564d8d; retrieved 2026-09-16T05:42:01.402Z.