ERA23LA173 · Beech P35
Beech P35 · Accident: loss of engine power (total) en route
From Peter O Knight Airport (TPF) to Apalachicola Regional Airport (AAF)
Event
- NTSB case
- ERA23LA173
- 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
- Event fatalities
- Unknown
- 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
Beech P35
- Aircraft type
- Beechcraft 35
- 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
- N9777Y
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Peter O Knight Airport (TPF), Tampa, FLTo Apalachicola Regional Airport (AAF), Apalachicola, FL
- Aircraft age
- About 60 years (built 1963)
- 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
- 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
- Loss of engine power (total)
- 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
About an hour into the flight, while cruising at 8,500 ft, light smoke entered the cabin momentarily, and the engine oil pressure dropped to zero. The pilot turned toward a nearby airport and shortly thereafter the engine lost power. Unable to glide to the airport, he saw a cleared field and set up for a forced landing. The airplane touched down on sandy soil, the nose gear dug in and separated, and the airframe was substantially damaged. The pilot was not injured. A postaccident examination of the engine revealed that the oil filter adapter separated at the engine case which likely resulted in a depletion of the engine’s oil supply and the subsequent total loss of engine power due to lack of lubrication. Residual oil covered the area around the adapter-to-engine case opening and below. The adapter threads appeared stripped. The adapter was safety wired in position and there was red torque putty applied as well. A review of the maintenance logbooks revealed that an annual inspection of the airframe and engine was completed about 29 hours before the accident. The logbook entries noted that an airworthiness directive that addressed security of the connection between the oil filter adapter and the engine case, including checking for proper torque, had been complied with during the inspection. The separation of the filter and stripping of the adapter threads were likely indicative of the oil filter adapter threads having failed due to improper torquing of the jam nut.
Probable cause
Maintenance personnel’s incorrect torquing of the oil filter adapter jam nut, resulting in the failure of the adapter threads, a complete loss of oil, and subsequent total loss of engine power.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA23LA173
- Event ID
- 20230330106979
- Case number
- ERA23LA173
- 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, cause areas. 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: e5737505e4bafddcad46ad791d5f727506b3b972d3b98e59ec88f60e88aedd4a; retrieved 2026-09-16T17:28:07.037Z.