# NTSB CEN23LA081: Pitts Model 12, N512P, Conroe, TX, January 14, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: January 14, 2023, 14:25 local (20:25 UTC) - Place: Conroe, TX · Intersection of League Line Road and Longmire Road, Montgomery Texas. - Coordinates: 30.306237, -95.462724 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.3062&lon=-95.4627&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 106584 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA081 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106584/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106584 - Page: https://openairdocs.org/ntsb/CEN23LA081 ## Probable cause The failure of the engine-driven fuel pump, which resulted in a total loss of engine power. Contributing to the failure of the fuel pump was an unknown non-ferrous metallic debris that was noted throughout the airplane’s fuel system. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuel system](https://openairdocs.org/ntsb-findings/01022800): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-findings/01022800/cases.md?model=05632JR), [All aircraft, 181 cases](https://openairdocs.org/ntsb-findings/01022800/cases.md) - [Engine fuel and control: fuel pump](https://openairdocs.org/ntsb-findings/01057314): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-findings/01057314/cases.md?model=05632JR), [All aircraft, 34 cases](https://openairdocs.org/ntsb-findings/01057314/cases.md) - [Fluids: fuel](https://openairdocs.org/ntsb-findings/01071010): Aircraft › Fluids/misc hardware · Fluid condition (probable cause); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-findings/01071010/cases.md?model=05632JR), [All aircraft, 1,695 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=05632JR), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Maneuvering: Fuel starvation](https://openairdocs.org/ntsb-events/191); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-events/191/sequence.md?model=05632JR), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Marc Jones PITTS MODEL 12, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05632JR), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot and passenger were conducting a local flight to practice maneuvers and landings. About 3 to 4 minutes after takeoff, and 2,000 ft above ground level, the pilot noticed a master warning light on instrument panel but did not notice any anomalies or problems. The pilot elected to return to the airport, and about 1 minute later the engine sustained a series of power loss fluctuations. The pilot attempted to troubleshoot the problem but was unsuccessful and the engine lost total power. Unable to reach the airport or a field due to a high descent rate, the pilot performed a forced landing to a nearby roadway. During the landing, the airplane impacted a powerline and terrain before coming to rest inverted. The airplane sustained substantial damage to the wings, fuselage, and empennage. Postaccident examination of the airplane revealed non-ferrous metallic debris throughout the entire fuel system; the source of the debris was unable to be determined. Due to a leak noted during a functional test, the engine-driven fuel pump was disassembled. Scratches and scoring marks were noted on the pressure relief valve seat, which allowed fuel into the air side cavity of the fuel pump. It is likely the fuel pump air cavity filled with fuel, which equalized the pump pressure and restricted fuel flow to the engine. The restricted fuel flow resulted in a total loss of engine power. ## Factual narrative On January 14, 2023, about 1425 central standard time, a Pitts Model 12 airplane, N512P, sustained substantial damage when it was involved in an accident near Conroe, Texas. The pilot sustained minor injuries and the passenger sustained serious injuries. The airplane was operated as a Code of Federal Regulations Part 91 personal flight. According to the pilot, he and the passenger were conducting a local flight to practice maneuvers and landings and the airplane contained about 40 gallons of fuel in the main fuel tank. About 3 to 4 minutes after takeoff, and at an altitude of 2,000 ft above ground level, the pilot noticed that a master warning light on the instrument panel illuminated but did not notice any anomalies or problems. The warning light then turned off, all indications were normal, and the engine was operating without issue. The pilot elected to return to the airport. The pilot stated that, about 1 minute later, the engine sustained a series of power fluctuations; “like someone was turning the [magnetos] off and on.” When the pilot turned on the fuel boost pump, the engine produced a burst of power, and then lost power. The pilot switched from the main fuel tank to the auxiliary tank with no change noted to engine power, then switched back to the main fuel tank. Unable to reach the airport or a field due to a high descent rate, the pilot performed a forced landing to a nearby roadway. During the landing, the airplane impacted a powerline and terrain before coming to rest inverted. The airplane sustained substantial damage to the wings, fuselage, and empennage (see Figure 1). Figure 1. Accident airplane as it came to rest (Source: Federal Aviation Administration) The airplane is equipped with a main fuel tank in the forward fuselage and a wing tank in the upper wing with a total capacity of 54 gallons. An aluminum header or inverted tank with a pickup (flop) tube is located beneath the main tank and provides the fuel supply for inverted flight. Postaccident examination of the airplane and engine revealed small particles of non-ferrous metal debris were noted throughout the airplane’s fuel system when fuel system components and fuel lines were removed. The airframe’s inverted fuel tank pickup tube was removed, and an o-ring at the end of the tube was not present. No evidence of the o-ring was noted in the fuel tank or fuel system. The engine was removed for a functional test in a test cell. The engine fuel pump was removed, flushed, and functionally bench tested before the functional engine test due to the presence of metal debris in the fuel system. During the functional test, a leak was noted at the pump’s rear pressure relief valve and rear diaphragm. Although the leak was present, the fuel pump flows were normal at idle and cruise power settings. The fuel pump was reinstalled on the engine for the engine functional test. During the engine prime procedure, the engine fuel pump leaked from the rear pressure relief valve and diaphragm,as observed during the bench test. Due to the potential fire and safety concerns, the pump was removed and replaced with a slave pump. The accident fuel pump was disassembled; scratches and scoring marks were noted on the pressure relief valve seat, which allowed fuel into the air side cavity of the fuel pump (see Figure 2). The diaphragm was pliable and undamaged. Blue stains, consistent with aviation fuel, were noted on the external pump housing. Figure 2. Engine fuel pump pressure relief valve with diaphragm After the fuel pump was replaced, the engine started on the test cell without issue. Around 800 rpms, a vertical vibration was observed with the engine and test cell stand. The functional test was terminated at that time due to the abnormal vibrations. ## Aircraft - Registration: [N512P](https://openairdocs.org/aircraft/N512P), registered now, S/N 291, built 2013 (OpenAirDocs) - Reported make and model: PITTS MODEL 12 - Registry model: [Marc Jones PITTS MODEL 12](https://openairdocs.org/model/marc-jones-pitts-model-12) (registry code 05632JR) (OpenAirDocs) - Registry engine: [Vedeneyev M14P](https://openairdocs.org/engine/vedeneyev-m14p) (registry code 63601, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 291 - Year built: 2013 - Airframe hours: 146.5 - Engines: Vedeneyev M-14P 421 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, November 27, 2022 - Airport: None - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: minor; flight engineer, flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review August 11, 2022; seat: rear; restraint: 5-point; flight hours: 34,000 total, 230 in this make and model, 32,000 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 32 °F - Altimeter: 30.22 inHg - Observed at: KCXO, 4 nm away - METAR: METAR KCXO 142053Z 15009KT 10SM CLR 17/00 A3022 RMK AO2 SLP231 T01720000 56039= ## 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 20230114002459A](https://openairdocs.org/incident/20230114002459A), Jan 14, 2023: Marc Jones PITTS MODEL 12, Montgomery, TX, Substantial damage. Pitts model 12, registration number[privacy data omitted] departed Conroe North Houston Airport (kcxo) and proceeded west. After 10 minutes into the flight at… ## Docket (5 files) The files NTSB released with the investigation on March 28, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106584. 5.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16031939&FileExtension=pdf&FileName=Doggett-6120_Redacted-Rel.pdf - Engine test summary (item 2, PDF, 5 pages, 616 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16032789&FileExtension=pdf&FileName=Engine%20Test%20Summary-Rel.pdf - Excerpt of airframe and engine logbooks (item 3, PDF, 2 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16032178&FileExtension=pdf&FileName=Excerpt%20of%20Airframe%20and%20Engine%20Logbook_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 4, PDF, 1 page, 237 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16032126&FileExtension=pdf&FileName=Signed%20Wreckage%20Release%20-%20N512P_Redacted-Rel.pdf - Investigation photograph (item 5, PDF, 2 pages, 989 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16032048&FileExtension=pdf&FileName=Photo%20Array-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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.