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CEN24LA286 · Piper PA46 310P

28 Jul 2024 · Radisson, WI, United States

Piper PA46 310P · Accident: loss of engine power (total) en route

From Lake in the Hills Airport (3CK) to Sawyer County Airport (HYR)

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Event

NTSB case
CEN24LA286
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Piper PA46 310P

Aircraft type
Piper PA46
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N4646G
Operator
Unknown
Onboard fatalities
Unknown
Route
From Lake in the Hills Airport (3CK), Lake in the Hills, ILTo Sawyer County Airport (HYR), Hayward, WI
Aircraft age
About 39 years (built 1985)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
En route · descent
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Loss of engine power (total)
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft power plant
  • Personnel issues › Action/decision
  • Personnel issues › Task performance

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

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.

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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CEN24LA286
Event ID
20240729194788
Case number
CEN24LA286
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status, cause areas. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: fc3012c546567c02fe4d53c2c454a442b97e3ab70645b694d753122a79b01b04; retrieved 2026-09-16T19:05:45.418Z.