# NTSB WPR20FA077: Stinson V77, N50249, Auburn, CA, January 24, 2020

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Class 3 · Field · Final report
- Date: January 24, 2020, 09:56 local (17:56 UTC)
- Place: Auburn, CA · Wooded terrain near hilltop
- Coordinates: 38.959445, -121.06583 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.9594&lon=-121.0658&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: Fatal
- Injuries: 2 fatal, 1 serious
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Admnistration
- NTSB case key (mKey): 100856
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20FA077
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100856/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100856
- Page: https://openairdocs.org/ntsb/WPR20FA077

## Probable cause

A total loss of engine power due to a combination of mechanical engine anomalies. Contributing to the accident was inadequate maintenance that failed to identify the engine anomalies.

## Findings

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

- [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=8631802), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Engine (reciprocating): recip eng wiring](https://openairdocs.org/ntsb-findings/01058597): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-findings/01058597/cases.md?model=8631802), [All aircraft, 8 cases](https://openairdocs.org/ntsb-findings/01058597/cases.md)
- [Ignition system: spark plugs/igniters](https://openairdocs.org/ntsb-findings/01057421): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-findings/01057421/cases.md?model=8631802), [All aircraft, 38 cases](https://openairdocs.org/ntsb-findings/01057421/cases.md)
- [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=8631802), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md)
- [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel; cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=8631802), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/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 (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=8631802), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Enroute: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Stinson VULTEE V-77, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=8631802), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot departed on a local flight with two passengers. Several witnesses reported that they heard the airplane’s engine backfiring and sputtering and subsequently heard the engine quit. The surviving passenger, who was seated in the front right seat, stated that the engine lost power and there was nowhere to land. The airplane subsequently impacted heavily wooded terrain about 1 mile from the departure airport. Postaccident examination of the engine revealed that the No. 7 cylinder intake valve was stuck open. The No. 2 cylinder front spark plug was defective, and the Nos. 2- and 4-cylinders’ ignition wires were frayed, worn, and displayed arcing, which likely led to erratic operation or a lack of ignition in these two cylinders. The culmination of these issues most likely led to the engine running rough, backfiring, and subsequently losing total power. An annual inspection was accomplished on the airframe and engine about 2 months before the accident. General maintenance practices and the inspection should have identified the anomalies that were found during the postaccident engine examination.

## Aircraft

- Registration: [N50249](https://openairdocs.org/deregistered/N50249-2020-10-31), registration cancelled 2020-10-31, S/N 77-458 (OpenAirDocs)
- Reported make and model: Stinson V77 (No Series)
- Registry model: [Stinson VULTEE V-77](https://openairdocs.org/model/stinson-vultee-v-77) (registry code 8631802) (OpenAirDocs)
- Category: Airplane
- Serial number: 77-458
- Engines: Pratt & Whitney 985 450 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 1, 2019
- Departed: AUN, Auburn, CA
- Destination: AUN, Auburn, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; injuries: fatal; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; toxicology performed; flight hours: 650 total
- Pilot-rated passenger; injuries: fatal; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: rear; toxicology performed; flight hours: 1,532 total
- Pilot-rated passenger; age 30; injuries: serious; private; airplane ratings: single-engine land; medical: class 2; seat: right; flight hours: 250 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 57 °F, dew point 50 °F
- Altimeter: 30.19 inHg
- Observed at: KAUN, 1 nm away

## 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 20200124001799A](https://openairdocs.org/incident/20200124001799A), Jan 24, 2020: Stinson VULTEE V-77, Auburn, CA, Substantial damage, 2 fatal. Flight originated from kaun at 0945 01/24/2020 departed from rwy 7 and turned crosswind. Aircraft then departed to the north. After flying for a few minutes,…

## Docket (13 files)

The files NTSB released with the investigation on May 4, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100856. 7.3 MB in all.

- Record of email (item 1, PDF, 2 pages, 144 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232673&FileExtension=pdf&FileName=Record%20of%20Email%20%20WPR20FA077%20Final-Rel.pdf
- Record of conversation (item 2, PDF, 4 pages, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232179&FileExtension=pdf&FileName=WPR20FA077%20Record%20of%20Conversation%20Final%201-Rel.pdf
- Witness reports (item 3, PDF, 2 pages, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13233023&FileExtension=pdf&FileName=Witness%20Reports_Redacted-Rel.pdf
- Flight route diagrams (item 4, PDF, 1 page, 691 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232920&FileExtension=pdf&FileName=Flight%20Route-Rel.pdf
- On site examination summary (item 5, PDF, 5 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13249545&FileExtension=pdf&FileName=WPR20FA077%20On%20Site%20Examination-Rel.pdf
- Engine examination summary (item 6, PDF, 5 pages, 802 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13249049&FileExtension=pdf&FileName=WPR20FA077%20Engine%20Examination%201-Rel.pdf
- Aircraft annual logbook excerpt (item 7, PDF, 1 page, 575 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232370&FileExtension=pdf&FileName=Aircraft%20Annual%20Final_Redacted-Rel.pdf
- Engine logbook excerpts (item 8, PDF, 3 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13721738&FileExtension=pdf&FileName=Engine%20Logbook%20Final_Redacted-Rel.pdf
- Engine manual excerpt (item 9, PDF, 1 page, 592 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232896&FileExtension=pdf&FileName=P%26W%20R-985%20Maintenance%20Manual%20Excerpt-Rel.pdf
- Flight route data (item 10, PDF, 8 pages, 135 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232380&FileExtension=pdf&FileName=WPR20FA0077%20Flight%20Route%20Data-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 11, PDF, 1 page, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232683&FileExtension=pdf&FileName=_2021%20Retention-Release-of-Wreckage-Form%20WPR20FA077%20Final_Redacted-Rel.pdf
- Toxicological report pilot (item 12, PDF, 1 page, 643 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232189&FileExtension=pdf&FileName=2020_016_001%20Pilot_Redacted-Rel.pdf
- Toxicological report passenger (item 13, PDF, 2 pages, 299 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13232886&FileExtension=pdf&FileName=2020_016_002%20Pilot%20Rate%20Passenger%20(Rear%20Seat)%202_Redacted-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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