# NTSB WPR21LA205: Boeing A75N1(PT17), N87WF, Ventura, CA, May 23, 2021

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: May 22, 2021, 19:18 local (May 23, 2021, 02:18 UTC)
- Place: Ventura, CA · Field - crops
- Coordinates: 34.283529, -119.31248 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.2835&lon=-119.3125&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- NTSB case key (mKey): 103148
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA205
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103148/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103148
- Page: https://openairdocs.org/ntsb/WPR21LA205

## Probable cause

The partial loss of engine power, during cruise flight, due to the formation of carburetor ice, which resulted in a forced landing to an open field where the airplane nosed over.

## Findings

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

- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Boeing A75N1(PT17), 4 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=1380134), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)
- [Object/animal/substance: ground equipment](https://openairdocs.org/ntsb-findings/03022050): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Boeing A75N1(PT17), 1 case](https://openairdocs.org/ntsb-findings/03022050/cases.md?model=1380134), [All aircraft, 52 cases](https://openairdocs.org/ntsb-findings/03022050/cases.md)
- [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=1380134), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md)

## Sequence of events

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

- [Enroute: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Boeing A75N1(PT17), 9 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1380134), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Boeing A75N1(PT17), 11 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=1380134), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot of the tailwheel equipped airplane reported that, while in cruse flight, about 1,200 to 1,500 ft above ground level (agl), near the Pacific coast, in visible moisture, the engine began to run rough. He applied full throttle and full carburetor heat. The engine initially regained power but again began to lose power at a progressively worsening rate. Concerned that he could not continue to the nearest airport he elected to land on a field. During the landing roll, the main landing gear impacted an irrigation line and the airplane nosed over coming to rest inverted. The rudder was substantially damaged. The pilot reported that there were no mechanical failures or malfunctions that would have precluded normal operation. Examination of the carburetor heat system by an airframe & powerplant mechanic revealed no mechanical anomalies. Weather conditions reported at the time of the accident were conducive for serious carburetor icing at any power setting.

## Aircraft

- Registration: [N87WF](https://openairdocs.org/aircraft/N87WF), registered now, S/N 75-3347 (OpenAirDocs)
- Reported make and model: BOEING A75N1(PT17)
- Registry model: [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17) (registry code 1380134) (OpenAirDocs)
- Category: Airplane
- Serial number: 75-3347
- Year built: 1942
- Airframe hours: 1487
- Engines: Continental R670 220 hp reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 8, 2021, 130 hours before
- Departed: IZA, Santa Ynez, CA
- Destination: SZP, Santa Paula, CA
- Airport: NA
- Equipment: ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; injuries: none; private, commercial, airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: rear; restraint: 4-point; flight hours: 2,850 total, 130 in this make and model, 2,150 as pilot in command, 150 in the last 90 days, 60 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 30° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 43 °F
- Altimeter: 30.05 inHg
- Observed at: KOXR, 7 nm away
- METAR: KOXR 221351Z 03005KT 10SM CLR 11/06 A3005 RMK AO2 SLP176 T01060061

## 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 20210522009909A](https://openairdocs.org/incident/20210522009909A), May 22, 2021: Boeing A75N1(PT17), Ventura, CA, Substantial damage. The pilot began to feel the engine running rough and then applied carburetor heat and full throttle. At that point the engine had lost power, the carburetor…

## Docket (6 files)

The files NTSB released with the investigation on August 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103148. 3.3 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12318790&FileExtension=pdf&FileName=N87WF%206120_Redacted-Rel.pdf
- Record of conversation (pilot) (item 2, PDF, 1 page, 127 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12339882&FileExtension=pdf&FileName=Memo%20for%20Record%20Pilot%20Interview-Rel.pdf
- Memo for record weather report (item 3, PDF, 1 page, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12609799&FileExtension=pdf&FileName=Memo%20for%20Record%20Weather%20Report-Rel.pdf
- Memo for record a & p mechanic (item 4, PDF, 1 page, 119 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12341538&FileExtension=pdf&FileName=Memo%20for%20Record%20A%26P%20Mechanic-Rel.pdf
- Icing probability chart (item 5, PDF, 1 page, 138 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12610100&FileExtension=pdf&FileName=Icing%20Probability%20Chart-Rel.pdf
- Photo (item 6, PDF, 1 page, 697 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12556075&FileExtension=pdf&FileName=Photos%20for%20WPR21LA205-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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