# NTSB CEN24LA286: Piper PA46, N4646G, Radisson, WI, July 28, 2024

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: July 28, 2024, 11:30 local (16:30 UTC)
- Place: Radisson, WI · Estimated: Open field near the intersection of Brisko Road and Weirgor Road.
- Coordinates: 45.733001, -91.261949 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.7330&lon=-91.2619&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: FAA Minneapolis FSDO, Continental Aerospace Technologies
- NTSB case key (mKey): 194788
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN24LA286
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194788/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194788
- Page: https://openairdocs.org/ntsb/CEN24LA286

## Probable cause

The non-certificated mechanic’s failure to properly tighten and torque the fuel system pressure test port cap, which resulted in a total loss of engine power, and a subsequent forced landing.

## 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 · Failure (probable cause); cases with it: [Piper PA-46-310P, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7104605), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piper PA-46-310P, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=7104605), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md)
- [Experience/qualifications: qualification/certification](https://openairdocs.org/ntsb-findings/02031010): Personnel issues › Experience/knowledge · Maintenance personnel; cases with it: [Piper PA-46-310P, 2 cases](https://openairdocs.org/ntsb-findings/02031010/cases.md?model=7104605), [All aircraft, 280 cases](https://openairdocs.org/ntsb-findings/02031010/cases.md)
- [Engine fuel and control](https://openairdocs.org/ntsb-findings/01057300): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-46-310P, 1 case](https://openairdocs.org/ntsb-findings/01057300/cases.md?model=7104605), [All aircraft, 49 cases](https://openairdocs.org/ntsb-findings/01057300/cases.md)
- [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Piper PA-46-310P, 2 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=7104605), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md)

## Sequence of events

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

- [Prior to flight: Security/criminal event](https://openairdocs.org/ntsb-events/350); cases with it: [Piper PA-46-310P, 1 case](https://openairdocs.org/ntsb-events/350/sequence.md?model=7104605), [All aircraft, 27 cases](https://openairdocs.org/ntsb-events/350/sequence.md)
- [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Piper PA-46-310P, 3 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=7104605), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md)
- [Enroute-descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-46-310P, 11 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7104605), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Piper PA-46-310P, 4 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=7104605), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md)
- [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-46-310P, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7104605), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Piper PA-46-310P, 2 cases](https://openairdocs.org/ntsb-events/490/sequence.md?model=7104605), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md)
- [Post-impact: Evacuation](https://openairdocs.org/ntsb-events/460); cases with it: [Piper PA-46-310P, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=7104605), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md)

## Analysis

The engine sustained a total loss of power when nearing the destination airport during a cross-country flight. The pilot performed a forced landing to a rural grass field and the airplane landed hard, coming to rest upright. The pilot was able to egress from the airplane without further incident. The airplane sustained substantial damage to the fuselage and the empennage. An on-site examination of the engine found that a cap was missing from the fuel pressure test port near the front top area of the engine. The test port is where a gauge would connect during maintenance work to test the fuel pressure. The test port and the aluminum housing that the port connects to both had blue staining. The exposed threading that the cap screws onto was found intact and the missing cap was not located. A review of the engine monitor performance data showed performance consistent with a total loss of engine power. The fuel flow rate had increased up to the maximum reading, about 80 gallons per hour, at the time the total loss of engine power occurred. A review of the most recent airplane maintenance records showed than an annual inspection was performed on the airframe, engine, and propeller about six weeks before the accident. The records reflected work completed on the fuel injection system, including the installation of new fuel injectors. According to the engine manufacturer, a fuel system operational check is required if fuel injectors are replaced. Test equipment is connected to the fuel pressure test port and a test is performed. Once the test work is completed, a cap is required to be tightened and torqued on the test port. The individual who performed the most recent annual inspections on the airplane did not hold an airframe and powerplant certificate, nor did he hold inspection authorization. The non-certificated mechanic signed off the annual inspections and returned the airplane to service using the airframe and powerplant mechanic certificate number of his deceased father, who held inspection authorization. The test port had blue staining present, and the exposed threading was found intact. The aluminum housing that the port connects to also had blue staining present. The blue staining was likely from a 100 low-lead fuel leak while in-flight. It is likely the loss of fuel and fuel system pressure caused a total loss of engine power. Based on the available evidence, it is likely that the non-certificated mechanic forgot to properly tighten and torque the fuel pressure test port cap, which resulted in a total loss of engine power. The non-certificated mechanic fraudulently represented himself as a certificated mechanic with inspection authorization and the appropriate knowledge, training, and experience by signing off the annual inspections and returning the airplane to service.

## Factual narrative

On July 28, 2024, about 1130 central daylight time, a Piper PA-46-310P airplane, N4646G, sustained substantial damage when it was involved in an accident near Radisson, Wisconsin. The commercial pilot sustained no injury. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal cross-country flight. The airplane departed from the Lake in the Hills Airport (3CK), Lake in the Hills, Illinois, about 0930. Before departure from 3CK, the pilot reported the airplane had 85 gallons of 100 low-lead fuel onboard. The airplane, operating on an instrument flight rules flight plan, traveled to the northwest, toward the destination of the Sawyer County Airport (HYR), Hayward, Wisconsin. About 25 miles southeast of HYR, the reciprocating engine sustained a total loss of power, and the pilot declared an emergency to air traffic control. The pilot performed a forced landing to a rural grass field containing trees. The airplane came to rest upright, and the pilot was able to egress from the airplane without further incident. The airplane sustained substantial damage to the fuselage and the empennage. An on-site examination of the engine by the FAA found that a cap was missing from the fuel pressure test port (a 90° brass elbow port) near the front top of the engine. The test port had blue staining present, and the exposed threading was found intact. The test port is where a gauge would connect during maintenance work to test the fuel pressure. The aluminum housing that the port connects to also had blue staining present. The missing cap was not recovered. A J.P. Instruments Engine Data Monitor 900 unit was removed from the airframe and the engine performance data was downloaded and reviewed. The engine performance data showed that the fuel flow rate had increased up to the maximum reading, about 80 gallons per hour, at the time the total loss of engine power occurred. Per the engine manufacturer the fuel system is a closed system. With the test port cap off, it becomes an open system, as shown with the blue staining in the two areas. As fuel is lost, fuel pressure is lost, and the engine then quits. A review of the most recent airplane maintenance records showed than an annual inspection was performed on the airframe, engine, and propeller on June 14, 2024, about 6 weeks before the accident. The records reflected work completed on the fuel injection system, including the installation of new fuel injectors. The entries for the annual inspections stated that the airplane was found in to be in an airworthy condition and the airplane was returned to service. According to the Continental Motors Standard Practice Maintenance Manual M-0, a fuel system operational check is required if fuel injectors are replaced. Test equipment is connected to the fuel pressure test port and a test is performed. Once the test work is completed, a cap (Continental Motors part number 639494) is required to be tightened and torqued on the test port. ContinentalMotors Standard Practice Maintenance Manual M-0 includes a warning that states: Failure to connect and torque fuel system fittings to the proper specification will result in a fuel leak and potential fire hazard. The individual who performed the most recent annual inspections on the airplane did not hold an airframe and powerplant certificate, nor did he hold inspection authorization. The non-certificated mechanic signed off the annual inspections and returned the airplane to service using the airframe and powerplant mechanic certificate number of his deceased father, who held inspection authorization. The father passed away on June 25, 2007.

## Aircraft

- Registration: [N4646G](https://openairdocs.org/deregistered/N4646G-2026-05-02), registration cancelled 2026-05-02, S/N 46-8508101, built 1985 (OpenAirDocs)
- Reported make and model: PIPER PA46 (310P)
- Registry model: [Piper PA-46-310P](https://openairdocs.org/model/piper-pa-46-310p) (registry code 7104605) (OpenAirDocs)
- Registry engine: [Continental TSIO-520-BE](https://openairdocs.org/engine/continental-tsio-520-be) (registry code 17277, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 46-8508101
- Year built: 1985
- Airframe hours: 5194.6
- Engines: Continental Motors TSIO-550C 350 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Piper Malibu N4646g LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 15, 2024, 20 hours before
- Departed: 3CK, Lake in the Hills, IL
- Destination: HYR, Hayward, WI
- Flight plan: IFR
- Equipment: Stall warning system, Onboard weather, Electronic primary flight display, ADS-B, Auto-pilot, Data recorder, Electronic flight bag or handheld device

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 58; injuries: none; private, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 18, 2024; seat: left; restraint: 3-point; flight hours: 2,400 total, 300 in this make and model, 23 in the last 90 days, 18 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 170° at 11 knots, gusting 14
- Temperature: 77 °F, dew point 68 °F
- Altimeter: 29.94 inHg
- Observed at: KRCX, 18 nm away
- METAR: KRCX 281615Z AUTO 17011G14KT SCT018 25/20 A2994 RMK AO2 T02520199 PWINO

## 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 20240728011999A](https://openairdocs.org/incident/20240728011999A), Jul 28, 2024: Piper PA-46-310P, Exeland, WI, Substantial damage. After a cross country flight, the PIC was instructed by ATC to descend from 6000 feet to 4000 feet. The PIC reduced power and descended. When the target…

## Docket (12 files)

The files NTSB released with the investigation on April 2, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194788. 43.2 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214301&FileExtension=pdf&FileName=NTSB%20Form%206120_1_Redacted-Rel.pdf
- Accident photographs (item 2, PDF, 6 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214291&FileExtension=pdf&FileName=Accident%20Photographs-Rel.pdf
- Pilot information (item 3, PDF, 3 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214208&FileExtension=pdf&FileName=Pilot%20Information_Redacted-Rel.pdf
- Most recent airplane maintenance records (item 4, PDF, 3 pages, 7.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18215386&FileExtension=pdf&FileName=Most%20Recent%20Airplane%20Maintenance%20Records_Redacted-Rel.pdf
- Federal aviation administration - N4646G examination report (item 5, PDF, 2 pages, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214198&FileExtension=pdf&FileName=FAA%20N4646G%20Examination%20Report_Redacted-Rel.pdf
- Continental aerospace technologies - standard practice maintenance manual excerpts (item 6, PDF, 9 pages, 25.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214823&FileExtension=pdf&FileName=Continental%20Aerospace%20Technologies%20-%20Standard%20Practice%20Maintenance%20Manual%20Excerpts-Rel.pdf
- Engine data monitor - specialist's factual report (item 7, PDF, 10 pages, 5 photos, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17972399&FileExtension=pdf&FileName=Enigne%20Data%20Monitor%20-%20Specialist%27s%20Factual%20Report-Rel.pdf
- Attachment 1 to engine data monitor - specialist's factual report (item 8, CSV, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17971994&FileExtension=csv&FileName=Attachment%201-Rel.csv
- Eugene edward haumschild - information (item 9, PDF, 3 pages, 687 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18216655&FileExtension=pdf&FileName=Eugene%20Edward%20Haumschild%20-%20Information-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 10, PDF, 2 pages, 157 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18215179&FileExtension=pdf&FileName=N4646G%20NTSB%20Wreckage%20Release%20Form_Redacted-Rel.pdf
- Evidence control form (item 11, PDF, 1 page, 141 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18215223&FileExtension=pdf&FileName=N4646G%20Evidence-Control-Form-Rel.pdf
- NTSB party member form - Continental aerospace technologies (item 12, PDF, 1 page, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18214940&FileExtension=pdf&FileName=NTSB%20Party%20Member%20Form%20CAT_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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