# NTSB ERA23LA173: Beech P35, N9777Y, Perry, FL, March 5, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: March 5, 2023, 16:45 local (21:45 UTC)
- Place: Perry, FL · Open farmland.
- Coordinates: 29.91105, -83.63894 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.9110&lon=-83.6389&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- ADs cited in the narratives: [AD 96-12-22](https://openairdocs.org/ad/96-12-22) (OpenAirDocs)
- NTSB case key (mKey): 106979
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA23LA173
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106979/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106979
- Page: https://openairdocs.org/ntsb/ERA23LA173

## 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.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Beech P35, 2 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=1151530), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md)
- [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech P35, 1 case](https://openairdocs.org/ntsb-findings/02061520/cases.md?model=1151530), [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Beech P35, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=1151530), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md)
- [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Beech P35, 3 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151530), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)

## Analysis

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.

## Factual narrative

On March 5, 2023, about 1645 eastern daylight time, a Beech P35 airplane, N9777Y, was substantially damaged when it was involved in an accident near Perry, Florida. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was on a cross-country flight from Peter O Knight Airport (TPF), Tampa, Florida, to Apalachicola Regional Airport (AAF), Apalachicola, Florida. 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 Perry-Foley Airport (FPY), Perry, Florida, 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. He lowered flaps to full and lowered the landing gear. The airplane touched down on sandy soil. The nose landing gear dug in and separated. The airplane came to rest upright and the pilot egressed the cockpit and was met by first responders. An initial examination of the wreckage by a Federal Aviation Administration inspector revealed that the lower, forward fuselage had structural damage. The pilot initially reported that the air hose to the oil-air separator failed, and the separator’s canister was split open and empty of oil. The engine crankcase did not contain any oil and the engine was seized. Oil covered the lower fuselage surfaces. Further examination of the engine by an airframe and powerplant mechanic revealed that the oil filter adapter was separated at the engine case. There was residual oil covering 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 on December 9, 2022. At the time of the accident, about 29 hours had accrued on the engine since the last annual inspection. The logbook entries noted that Airworthiness Directive (AD) 96-12-22 had been complied with. The AD addressed security of the connection (jam nut) between the oil filter adapter and the engine case, including checking for proper torque. An article from AOPA [Aircraft Owners and Pilots Association] Pilot Magazine, dated May 5, 2005, addressed the oil filter adapter AD. The article stated that, “If the proper torque isn’t applied to the jam nut, the weight of the oil-filled filter combined with normal vibrations will soon cause thread damage to the adapter. In a few cases maintenance practices have been so mindless that the threads got in bad enough shape that the adapter was blown completely out of the engine.”

## Aircraft

- Registration: [N9777Y](https://openairdocs.org/aircraft/N9777Y), registered now, S/N D-7160, built 1963 (OpenAirDocs)
- Reported make and model: BEECH P35
- Registry model: [Beech P35](https://openairdocs.org/model/beech-p35) (registry code 1151530) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: D-7160
- Year built: 1963
- Airframe hours: 5364
- Engines: CONT MOTOR I0-470 SERIES 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 9, 2022, 29 hours before
- Departed: TPF, Tampa, FL
- Destination: AAF, Apalachicola, FL
- Airport: None
- Equipment: Electronic flight bag or handheld device, ADS-B, Satellite tracking device

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review February 14, 2023; seat: left; restraint: lap only; flight hours: 70 total, 16 in this make and model, 31 as pilot in command, 30 in the last 90 days, 3 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 9 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point 63 °F
- Altimeter: 30.08 inHg
- Observed at: KAAF, 73 nm away
- METAR: METAR KAAF 052053Z AUTO 13009KT 10SM CLR 24/17 A3008 RMK AO2 SLP186 T02440172 56008 $

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20230305009489A](https://openairdocs.org/incident/20230305009489A), Mar 5, 2023: Beech P35, Perry, FL, Substantial damage. [privacy data omitted] BE35, reported engine issues and Made an emergency landing in a field 10 miles South of fpy (Perry-Foley, FL).

## Docket (11 files)

The files NTSB released with the investigation on June 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106979. 20.5 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15661445&FileExtension=pdf&FileName=1%206120.1%20Pilot_Operator%20Aircraft%20Accident_Incident%20Report_Redacted-Rel.pdf
- Pilot's written statement to FAA (item 2, PDF, 2 pages, 919 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15662205&FileExtension=pdf&FileName=2%20Pilot%20Written%20Statement%20to%20FAA%20(2)_Redacted-Rel.pdf
- NTSB memorandum for record - mechanic statement (item 3, PDF, 1 page, 95 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15662086&FileExtension=pdf&FileName=3%20NTSB%20MOR%20Mechanic%20Statement_Redacted-Rel.pdf
- Excerpt - aircraft logbook (item 4, PDF, 1 page, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15662456&FileExtension=pdf&FileName=4%20Mx%20Log%20Airframe_Redacted-Rel.pdf
- Excerpt - engine logbook (item 5, PDF, 1 page, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15661983&FileExtension=pdf&FileName=5%20Mx%20Log%20Engine_Redacted-Rel.pdf
- Memorandum for record - aircraft time since last inspection discrepancy (item 6, PDF, 2 pages, 899 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17164931&FileExtension=pdf&FileName=NTSB%20MOR%20Aircraft%20Time%20Since%20Inspection%20Discrepancy_Redacted-Rel.pdf
- Photo array (item 7, PDF, 4 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15662322&FileExtension=pdf&FileName=5a%20Photo%20Array-Rel.pdf
- Video provided by A&P mechanic showing oil filter adapter separation - 1 (item 8, MOV, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15665185&FileExtension=MOV&FileName=7%20Video_1-Rel.MOV
- Video provided by A&P mechanic showing oil filter adapter separation - 2 (item 9, MOV, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15664778&FileExtension=MOV&FileName=8%20Video%202-Rel.MOV
- Airworthiness directive 96-12-22 (item 10, PDF, 4 pages, 239 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15661993&FileExtension=pdf&FileName=6%20FAA%20AD%2096-12-22-Rel.pdf
- Aopa pilot article (item 11, PDF, 5 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15663813&FileExtension=pdf&FileName=AOPA%20Pilot%20Article-Rel.pdf

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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