# NTSB CEN21LA078: Vans RV4, N423WH, Sadler, TX, December 7, 2020

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 3 · Limited · Final report
- Date: December 7, 2020, 15:28 local (21:28 UTC)
- Place: Sadler, TX
- Coordinates: 33.68201, -96.844602
- Nearby events: https://openairdocs.org/map.md?lat=33.6820&lon=-96.8446&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Defining event: [Takeoff-rejected takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: Australian Transport Safety Bureau, FAA NTX FSDO
- NTSB case key (mKey): 102386
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA078
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102386/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102386
- Page: https://openairdocs.org/ntsb/CEN21LA078

## Probable cause

The partial loss of engine power for reasons that could not be determined based on the available evidence.

## Findings

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

- [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined; cases with it: [Hall Wendell VANS RV-4, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=05604MP), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md)

## Sequence of events

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

- [Takeoff-rejected takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Hall Wendell VANS RV-4, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05604MP), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Landing-landing roll: Landing area overshoot](https://openairdocs.org/ntsb-events/380); cases with it: [Hall Wendell VANS RV-4, 1 case](https://openairdocs.org/ntsb-events/380/sequence.md?model=05604MP), [All aircraft, 400 cases](https://openairdocs.org/ntsb-events/380/sequence.md)
- [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Hall Wendell VANS RV-4, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=05604MP), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot was practicing low approaches at a private grass airstrip and elected to land. He determined he would land too far down the runway and initiated a go-around. The engine initially responded, but the engine power then reduced to idle. He “pumped the throttle” two or three times, and the engine did not respond. He subsequently landed on the runway. The airplane overran the end of the runway and nosed over, which resulted in substantial damage to the rudder, elevator, and left wing. Postaccident engine runs were conducted with the engine attached to the airframe. The engine started and attempts were made to increase engine rpm. The engine would sputter and lose power momentarily each time the throttle was advanced. During one engine run, the engine stopped when the throttle was advanced. During the final engine run, the engine would not shut down normally using the throttle and mixture control, but it shut down when the ignition was turned off. The engine, airframe, and throttle body unit were examined, and no preimpact anomalies were noted. Functional testing of the throttle body unit could not be completed due to a lack of access to appropriate test equipment. The reason for the partial loss of engine power could not be determined based on the available evidence.

## Factual narrative

On December 7, 2020, at 1528 central standard time, a Vans RV-4 airplane, N423WH, was substantially damaged when it was involved in an accident near Sadler, Texas. The pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot told investigators he had been practicing low approaches at a private grass airstrip and elected to land. He determined he would land too far down the runway and initiated a go-around. The engine initially responded, but the engine power then reduced to idle. He “pumped the throttle” two or three times, and the engine did not respond. He subsequently landed on the runway. The airplane overran the end of the runway and nosed over, which resulted in substantial damage to the rudder, elevator, and left wing. Postaccident engine runs were conducted with the engine attached to the airframe. The engine started on the third attempt and was allowed to idle for about 2.5 minutes. The engine remained at about 1,050 rpm during that time. Several attempts were subsequently made to increase engine rpm. The engine would sputter and lose power momentarily each time the throttle was advanced. During one engine run, the engine stopped following an attempt to advance the throttle. The engine started again on the fourth attempt. The sputtering and loss of power repeated during each attempt to advance the throttle above idle. The engine was allowed to idle and attempts to shut down the engine normally using the throttle and mixture controls were unsuccessful. The engine shut down when the ignition was turned off. The engine was equipped with a Rotech Mk.II 48-4/5 throttle body injector (TBI) unit. Examination revealed both the throttle and mixture controls were secured properly to the TBI unit. The TBI was removed from the engine and examined. No anomalies were noted during examination of the TBI that would have precluded normal operations. Functional testing of the TBI could not be completed due to a lack of access to appropriate test equipment.

## Aircraft

- Registration: [N423WH](https://openairdocs.org/deregistered/N423WH-2021-05-08), registration cancelled 2021-05-08, S/N 3349, built 1997 (OpenAirDocs)
- Reported make and model: VANS RV4
- Registry model: [Hall Wendell VANS RV-4](https://openairdocs.org/model/hall-wendell-vans-rv-4) (registry code 05604MP) (OpenAirDocs)
- Registry engine: [Lycoming I0360 SER A&C](https://openairdocs.org/engine/lycoming-i0360-ser-a-c) (registry code 41511, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 3349
- Year built: 1997
- Airframe hours: 1231
- Engines: Lycoming Penn Yan IO-360-EXP 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, January 22, 2019, 16 hours before
- Departed: KSWI, Sherman, TX
- Destination: Same as departure
- Airport: 15TX, Flying J Airport, runway 18, 790 × 75 ft, grass/turf
- Equipment: Electronic multifunction display, Auto-pilot, ADS-B, Electronic primary flight display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 74; injuries: minor; airline transport, flight instructor, flight engineer; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; last flight review July 11, 2020; seat: front; restraint: 5-point; flight hours: 14,750 total, 2.9 in this make and model, 9,900 as pilot in command, 2.9 in the last 90 days, 2.9 in the last 30 days, 2.9 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point 34 °F
- Altimeter: 29.51 inHg
- Observed at: KGLE, 20 nm away
- METAR: 3:53 PM	63 °F	34 °F	34 %	WNW	7 mph	0 mph	29.51 in	3:53 PM	63 °F	34 °F	34 %	WNW	7 mph	0 mph	29.51 in	0.0 in	Fair

## 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 20201207022159A](https://openairdocs.org/incident/20201207022159A), Dec 7, 2020: Hall Wendell VANS RV-4, Sadler, TX, Substantial damage. Pilot was performing touch-and-goes on his home strip. After advancing the throttle, the engine spooled up, then dropped to idle. The pilot was unable to stop…

## Docket (4 files)

The files NTSB released with the investigation on July 13, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102386. 5.3 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 4.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13579696&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf
- Engine run notes (item 2, PDF, 1 page, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13725466&FileExtension=pdf&FileName=Memorandum%20of%20Record%20-%20Engine%20Run-Rel.pdf
- Tbi examination notes (item 3, PDF, 2 pages, 118 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13723048&FileExtension=pdf&FileName=Memorandum%20of%20Record%20-%20TBI%20Exam-Rel.pdf
- Photos (item 4, PDF, 4 pages, 4 photos, 819 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13583853&FileExtension=pdf&FileName=Photo%20Array%20-%20CEN21LA078-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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