# NTSB ERA23LA345: Waco UPF-7, N39721, Warrenton, VA, August 20, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: August 20, 2023, 19:30 local (23:30 UTC)
- Place: Warrenton, VA
- Coordinates: 38.550401, -77.715824 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.5504&lon=-77.7158&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 192912
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA23LA345
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192912/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192912
- Page: https://openairdocs.org/ntsb/ERA23LA345

## Probable cause

A ground loop during landing resulting from a partial separation of the right main landing gear strut during takeoff.

## Findings

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

- [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Waco UPF-7, 4 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=9601302), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md)
- [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Waco UPF-7, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=9601302), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md)

## Sequence of events

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

- [Takeoff: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Waco UPF-7, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=9601302), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md)
- [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Waco UPF-7, 2 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=9601302), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md)

## Analysis

According to the pilot, after takeoff in the vintage tailwheel-equipped biplane, he was notified via radio that the right main landing gear was partially separated from the airframe. The pilot, returned to the airport and during landing, he continued to fly the airplane down the runway with the right main landing gear in the air until the airplane decelerated and settled onto the turf runway. Once the airplane slowed, it “ground loop[ed]” and came to rest on the nose, which resulted in substantial damage to the left wing. Postaccident examination revealed that the inner strut had separated from the outer strut but remained partially attached.

## Aircraft

- Registration: [N39721](https://openairdocs.org/aircraft/N39721), registered now, S/N 5854, built 1942 (OpenAirDocs)
- Reported make and model: WACO UPF-7
- Registry model: [Waco UPF-7](https://openairdocs.org/model/waco-upf-7) (registry code 9601302) (OpenAirDocs)
- Registry engine: [Continental W670 series](https://openairdocs.org/engine/continental-w670-series) (registry code 17018, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 5854
- Year built: 1942
- Engines: Continental R-670-6A 220 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 1, 2023
- Destination: Same as departure
- Airport: 3VA3, Flying Circus Aerodrome, runway 22, 2,500 × 200 ft, grass/turf
- Equipment: ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; injuries: none; commercial; airplane ratings: single-engine sea, single-engine land; medical: unknown, unknown

## Weather

- Conditions: Visual (VMC), Day
- Wind: 170° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 59 °F
- Altimeter: 30.09 inHg
- Observed at: HWY, 2 nm away
- METAR: KHWY 202335Z AUTO 17003KT 10SM CLR 29/15 A3009 RMK AO2 T02910145


## 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 20230820014519A](https://openairdocs.org/incident/20230820014519A), Aug 20, 2023: Waco UPF-7, Warrenton, VA, Substantial damage. On 8/20/2023 around 7:30 pm [privacy data omitted] was conducting an air tour ride. After take off the ground crews noticed the right gear was hanging out of…

## Other investigations on N39721 (1)

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.

- [NTSB MIA89IA080](https://openairdocs.org/ntsb/MIA89IA080), Feb 6, 1989: Waco UPF-7 (N39721), Marathon, FL, incident, minor damage. Probable cause: FUEL STARVATION DUE TO A CORRODED CARBURETOR.

## Docket (3 files)

The files NTSB released with the investigation on November 16, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192912. 50.3 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 7 pages, 49.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16293131&FileExtension=pdf&FileName=6120%20LA345_Redacted-Rel.pdf
- Memorandum for record - FAA inspector (item 2, PDF, 1 page, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16293506&FileExtension=pdf&FileName=Memo%20-%20FAA%20Inspector%20LA345-Rel.pdf
- Investigative photographs (item 3, PDF, 3 pages, 857 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16293526&FileExtension=pdf&FileName=Photos%20LA345-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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