# NTSB WPR23LA239: Piper PA-24-250, N6430P, Alturas, CA, June 25, 2023 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: June 25, 2023, 09:00 local (16:00 UTC) - Place: Alturas, CA · airport environment - Coordinates: 41.482861, -120.56541 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.4829&lon=-120.5654&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 192448 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA239 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192448/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192448 - Page: https://openairdocs.org/ntsb/WPR23LA239 ## Probable cause A loss of engine power due to the failure of the right magneto distributor gear and the pilot’s decision to conduct a test flight with known mechanical issues. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-24-250, 7 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7102404), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Ignition system: magneto/distributor](https://openairdocs.org/ntsb-findings/01057414): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Piper PA-24-250, 2 cases](https://openairdocs.org/ntsb-findings/01057414/cases.md?model=7102404), [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/01057414/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-24-250, 23 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7102404), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-24-250, 23 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102404), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Piper PA-24-250, 6 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=7102404), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot reported that, shortly after takeoff, the airplane’s engine began to run rough, so he returned to the airport, landed uneventfully, parked the airplane, and deplaned his passengers to conduct another preflight inspection. The pilot sampled the fuel, checked for loose spark plugs, and checked the magnetos. The pilot then decided to do an engine run-up and test flight before departing the area with the passengers. After takeoff, about 100 ft above ground level (agl), the engine began to shake violently, and he initiated a turn back to the airport. The engine lost total power, and the airplane landed hard and came to rest upright in the grass adjacent to the runway, resulting in substantial damage to fuselage, both wings, and the right horizontal stabilizer. Postaccident examination of the engine established mechanical and valvetrain continuity. When the propeller was rotated, the No. 5 ignition harness top lead did not spark. The right magneto was removed and functionally tested with an intermittent spark. The left magneto was also removed, and spark was obtained on all posts during the functional check. Further testing revealed that the intermittent spark from the right magneto could not be duplicated. Disassembly of right magneto revealed about 1/4 of the teeth were separated from the distributor gear, which would likely result in a partial loss of engine power and a rough running engine. No additional evidence of any preexisting mechanical malfunctions that would have precluded normal operation were observed with either magneto. ## Factual narrative On June 25, 2023, at 0900, Pacific daylight time, a Piper PA-24-250, N6430P, was substantially damaged when it was involved in an accident near Alturas, California. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, after departure from Alturas Municipal Airport (AAT), with two passengers onboard, the engine began to miss and run rough. He returned to the airport, landed uneventfully, parked, and exited the airplane. He stated that he performed a full preflight inspection of the airplane, which included sampling fuel from all four fuel tanks and checking for “loose spark plugs, mags, [etc].” All engine components “looked good.” The pilot stated that he wanted to do an engine run up and test flight without his passengers before continuing the flight to their intended destination. The pilot stated that the pre-takeoff engine run up was normal, and he departed from runway 21. After climbing “a couple hundred feet,” the engine began to violently shake. The pilot initiated a left turn back to the airport and the engine lost all power. The airplane descended, landed hard, and came to rest upright in the grass adjacent to the runway. The on-site examination revealed that the airplane remained upright and intact with substantial damage to the fuselage, both wings and the right horizontal stabilizer. Postaccident examination of the airframe revealed no preimpact mechanical malfunctions that would have precluded normal operation. Postaccident examination of the engine revealed several pin holes in the exhaust tube surrounding the exhaust gas temperature (EGT) probe hole. Mechanical and valvetrain continuity was established via manual rotation of the propeller. However, when the propeller was rotated, spark from the ignition harness No. 5 top lead was not present. Both magnetos were intact and secure at their respective mounting pads. The right magneto was removed and a functional test garnered intermittent spark. The left magneto was also removed and functionally checked with no discrepancies. Both magnetos were shipped to Continental Aerospace Technologies with no discrepancies noted during a bench test. The right magneto was disassembled and about 1/4 of the distributor gear teeth were found separated from the distributor gear. No evidence of any additional mechanical anomalies was observed with either magneto. No maintenance records for the magnetos, engine or airframe were made available during the investigation. ## Aircraft - Registration: [N6430P](https://openairdocs.org/aircraft/N6430P), registered now, S/N 24-1540, built 1959 (OpenAirDocs) - Reported make and model: PIPER PA-24-250 - Registry model: [Piper PA-24-250](https://openairdocs.org/model/piper-pa-24-250) (registry code 7102404) (OpenAirDocs) - Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 24-1540 - Year built: 1959 - Airframe hours: 3724 - Engines: Lycoming O-540-A1C5 250 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 16, 2022 - Destination: Same as departure - Airport: AAT, Alturas Muni, runway 21, 2,506 × 60 ft, asphalt - Equipment: Stall warning system, Electronic primary flight display, Auto-pilot, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: minor; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: basicmed; last flight review October 22, 2021; seat: left; restraint: lap only; flight hours: 390 total, 168 in this make and model, 318 as pilot in command, 5 in the last 90 days, 4 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 48 °F - Altimeter: 30.13 inHg - Observed at: KAAT - METAR: KAAT 251555Z AUTO 00000KT 10SM CLR 13/09 A3013 RMK AO2 SLP179 T01280094 ## 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 20230625013129A](https://openairdocs.org/incident/20230625013129A), Jun 25, 2023: Piper PA-24-250, Alturas, CA, Destroyed. Pilot's written statement: "IFR flight plan on file kaat. Sky was clear. I planned on getting seattle center once airborne. Got weather on ATIS. Did normal… ## Docket (6 files) The files NTSB released with the investigation on July 8, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192448. 13.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 7.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15788910&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photos (item 2, PDF, 6 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18839628&FileExtension=pdf&FileName=WPR23LA239%20Photos-Rel.pdf - Engine exam report (item 3, PDF, 12 pages, 2.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18846233&FileExtension=pdf&FileName=Engine%20Examination%20Report-Rel.pdf - Magneto exam summary (item 4, PDF, 5 pages, 575 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18845991&FileExtension=pdf&FileName=Magento%20Exam%20Summary%20-WPR23LA239-Rel.pdf - Magneto examination (NTSB) (item 5, PDF, 2 pages, 2 photos, 408 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18869903&FileExtension=pdf&FileName=mag%20exam-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (airplane) (item 6, PDF, 2 pages, 160 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18808565&FileExtension=pdf&FileName=WPR23LA239%20Retention-Release-of-Wreckage-Form%20-%20SIGNED_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. --- 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.