CEN18LA086 · Swearingen SA227 TT
Airco JN Swearingen SA227 TT · Accident: electrical system malfunction/failure en route
From Jack Brooks Regional Airport (BPT) to Garner Field (UVA)
Event
- NTSB case
- CEN18LA086
- 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
Swearingen SA227 TT
- Aircraft type
- Swearingen SA227
- 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
- N6UP
- Operator
- Airco JN
- Onboard fatalities
- Unknown
- Route
- From Jack Brooks Regional Airport (BPT), Beaumont, TXTo Garner Field (UVA), Uvalde, TX
- Aircraft age
- About 37 years (built 1981)
- 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
- Electrical system 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
- Aircraft › Aircraft systems
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
During a corporate flight, as the pilots climbed the airplane to flight level 180, both electrical generators failed and would not reset. The pilots attempted to troubleshoot the problem but could not regain electrical power. The airplane's battery power was rapidly deteriorating, so the pilots declared an emergency and diverted to the nearest airport. Due to the loss of electrical power, the pilots lost communications and had to manually extend the landing gear. They could not verify, with air traffic control tower personnel, if the landing and nose gear were extended and locked. The pilots made a forced landing with the nose landing gear not fully extended, causing the airplane to skid on the forward fuselage after touchdown and substantially damaging the engines.
Postaccident examination of the airplane revealed the right generator current limiter had failed. A mechanic connected a battery to the airplane, and the left propeller immediately began to rotate. The mechanic determined that there was uncommanded voltage to the left starter, which was caused by a failure of the left starter relay when the engine was started before the flight. During the flight, the right generator was managing all of the airplane's electrical load, the cumulative electrical load exceeded the capacity of the right generator current limiter, and the generator failed. At that point, the airplane's electrical load was only being supplied by battery power, which was quickly depleted. Postaccident examination of the nose landing gear did not identify a mechanical reason to explain why the nose landing gear did not extend during the pilots' emergency landing gear extension procedure.
Probable cause
The failure of the left starter relay during engine start, which resulted in a loss of electrical and battery power during the flight and led to a forced landing with the nose landing gear not fully extended, causing substantial damage to the engines.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN18LA086
- Event ID
- 20180130X90601
- Case number
- CEN18LA086
- 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, 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: aef50434813fa465031ee089ffcc6d7e16319fb063939d9258649b1240ce5fd0; retrieved 2026-09-16T06:24:53.419Z.