# NTSB WPR23LA134: Harris Robert W Zenith CH 801, N639BH, Brigham City, UT, March 11, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: March 11, 2023, 11:30 local (18:30 UTC)
- Place: Brigham City, UT · On airport
- Coordinates: 41.554306, -112.06225
- Nearby events: https://openairdocs.org/map.md?lat=41.5543&lon=-112.0623&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 106921
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA134
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106921/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106921
- Page: https://openairdocs.org/ntsb/WPR23LA134

## Probable cause

The pilot’s improper flare, which resulted in a hard landing following a reported loss of engine thrust for undetermined reasons.

## Findings

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

- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Harris Robert W ZENITH CH 801, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=05621TL), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot; cases with it: [Harris Robert W ZENITH CH 801, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05621TL), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Performance/control parameters: landing flare](https://openairdocs.org/ntsb-findings/01062041): Aircraft › Aircraft oper/perf/capability · Not attained/maintained; cases with it: [Harris Robert W ZENITH CH 801, 1 case](https://openairdocs.org/ntsb-findings/01062041/cases.md?model=05621TL), [All aircraft, 1,285 cases](https://openairdocs.org/ntsb-findings/01062041/cases.md)

## Sequence of events

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

- [Takeoff: Unknown or undetermined](https://openairdocs.org/ntsb-events/000); cases with it: [Harris Robert W ZENITH CH 801, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=05621TL), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md)
- [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Harris Robert W ZENITH CH 801, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=05621TL), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md)

## Analysis

The pilot reported that the airplane sustained a loss of engine thrust during the initial takeoff climb, but the engine continued to run. The pilot elected to land on the remaining runway; however, during the landing flare, the airplane landed hard on its nose and the nose landing gear collapsed. Additionally, the pilot stated that he defueled about 40 gallons of fuel from the airplane after the accident. A visual inspection of the fuel system was conducted, and continuity was established from the main fuel tanks throughout the system; however, fuel was not observed within the fuel system. A postaccident engine ground run was accomplished, and the engine performed at various power settings. Due to a damaged propeller, the propeller governor was removed and functionally tested; it performed within manufacturer's specifications. Postaccident examination of the airplane’s engine revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Examination of the propeller governor indicated no visible signs of damage and the governor control lever moved freely from stop to stop. The propeller governor was functionally tested and performed within the manufacturer's specifications. While it’s likely that the loss of engine thrust may have been fuel related, it could not be substantiated due to the available evidence.

## Factual narrative

On March 11, 2023, about 1130 mountain daylight time, an experimental amateur-built Zenith CH 801, N638BH, was substantially damaged when it was involved in an accident near Brigham City, Utah. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Brigham City Regional Airport (BMC) and while ascending, about 200 to 300 ft above ground level, the airplane sustained a loss of thrust, but the engine continued to run. Unable to maintain altitude, the pilot elected to land on the remaining runway. Subsequently, the airplane landed hard, and the nose landing gear collapsed. The pilot stated that he defueled about 40 gallons of fuel from the airplane after the accident. A pilot-rated passenger in the airplane reported that, during the first lap in the pattern, while on the downwind leg, the engine rpm seemed to fluctuate, as if the engine was surging. Not having been in this type of airplane before, he did not know if the fluctuating rpm was normal. While on final approach to land, the pilot moved the propeller control full forward, landed the airplane, and started to take off again. However, during the initial takeoff climb, the pilot stated he had no power. The passenger looked at the engine rpm and it seemed normal. The pilot then said, ‘we got the power back’. The passenger noticed they had plenty of runway and recommended the pilot land the airplane. During the landing flare, the airplane landed hard. Postaccident examination of the airplane identified structural bending of the aft fuselage. Flight control continuity was established from all primary flight control surfaces to the cockpit controls. Examination of the recovered airframe and engine revealed no preaccident mechanical failures or malfunctions that would have precluded normal operation. A visual inspection was conducted of the fuel system. Continuity was established from the main fuel tanks throughout the system to the carburetor. The airframe fuel strainer was void of fuel. An external fuel source was mounted to the right-wing fuel inlet line to facilitate a test run. The engine started during the initial attempt and ran through various power settings uneventfully for about 5 minutes. Due to the damaged propeller, the throttle was not advanced to the full power position. However, the engine did produce a static rpm of 2,600. The propeller governor was removed for further examination. There were no visible signs of damage and the governor control lever moved freely from stop to stop. The propeller governor was functionally tested and performed within the manufacturer's specifications.

## Aircraft

- Registration: [N639BH](https://openairdocs.org/aircraft/N639BH), registered now, S/N 841534 (OpenAirDocs)
- Reported make and model: HARRIS ROBERT W ZENITH CH 801
- Registry model: [Harris Robert W ZENITH CH 801](https://openairdocs.org/model/harris-robert-w-zenith-ch-801) (registry code 05621TL) (OpenAirDocs)
- Registry engine: [Franklin 6A-350SER](https://openairdocs.org/engine/franklin-6a-350ser) (registry code 27023, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 841534
- Year built: 2006
- Airframe hours: 21
- Engines: Franklin PZLR-6A-350CIR 220 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, September 6, 2022
- Destination: Same as departure
- Airport: BMC, Brigham City Rgnl, runway 35, 8,900 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 65; injuries: none; private; airplane ratings: single-engine land; medical: basicmed, with waivers/limitations; last flight review October 22, 2021; seat: left; flight hours: 505 total, 14 in this make and model, 335 as pilot in command, 9 in the last 90 days, 6 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 36 °F, dew point 23 °F
- Altimeter: 30.01 inHg
- Observed at: KBMC
- METAR: METAR KBMC 111830Z AUTO 34004KT 10SM CLR 02/M05 A3001 RMK AO1 T00151048=

## 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 20230311003749A](https://openairdocs.org/incident/20230311003749A), Mar 11, 2023: Harris Robert W ZENITH CH 801, Brigham City, UT, Substantial damage. The pilot states he took off from Brigham City airport on runway 35 and planned "to do a few touch and go's". Pilot states he went around the pattern one time…

## Docket (8 files)

The files NTSB released with the investigation on June 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106921. 7.3 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16451880&FileExtension=pdf&FileName=NTSB%20form%206120_Redacted-Rel.pdf
- Record of e-mail correspondence (pilot) (item 2, PDF, 1 page, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16538514&FileExtension=pdf&FileName=Record%20of%20e-mail%20correspondence%20(pilot)-Rel.pdf
- Record of phone conversation (passenger) (item 3, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16460915&FileExtension=pdf&FileName=Record%20of%20phone%20conversation%20(Passenger)-Rel.pdf
- Airframe and engine examination (item 4, PDF, 8 pages, 965 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17127966&FileExtension=pdf&FileName=WPR23LA134%20Airframe%20and%20Engine%20Examination-Rel.pdf
- Propeller governor examination (item 5, PDF, 4 pages, 448 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17127518&FileExtension=pdf&FileName=WPR23LA134%20Propeller%20Governor%20Examination-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 6, PDF, 1 page, 540 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16584537&FileExtension=pdf&FileName=WPR23LA134%20Retention%20Release%20of%20Wreckage_Redacted-Rel.pdf
- Evidence control form (item 7, PDF, 2 pages, 174 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16537800&FileExtension=pdf&FileName=WPR23LA134%20Evidence%20Control%20Form_Redacted-Rel.pdf
- Photo array (item 8, PDF, 4 pages, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16460695&FileExtension=pdf&FileName=Photo%20Array_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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