SEA05LA170 · Piper PA-24-250
Piper PA-24-250 · Accident: airframe, component or system failure en route
From Challis Airport (KLLJ) to Mackay Airport (U62)
Event
- NTSB case
- SEA05LA170
- 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
- Unknown
- 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 PA-24-250
- Aircraft type
- Piper PA-24
- 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
- N6677P
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Challis Airport (KLLJ), Challis, IDTo Mackay Airport (U62), MACKAY, ID
- Aircraft age
- Not recorded
- 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 · climb to cruise
- First occurrenceThe 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
- Airframe, component or system failure
- 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
- Fluid, oil › Loss, total
- Lubricating system, oil gasket › Failure
- Lubricating system, oil gasket › Incorrect
- Other maintenance personnel › Maintenance, overhaul, improper
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot reported that shortly after takeoff, the propeller RPM became erratic and uncontrollable and he elected to return to the airport. He reported that during the descent, the airplane developed a rough running engine and eventually lost power resulting in an off airport landing. Preliminary external examination of the assembly revealed a large hole in the engines crankcase, adjacent to the number four cylinder assembly. The number four piston rod was fractured and extensive heat distress, deformation and discoloration was noted to both the number three and number four piston assemblies. A representative from Textron Lycoming reported that this type of damage is indicative of oil depravation. Further examination of the engine assembly revealed that the hydraulic pump adapter pad cover gasket was protruding from between the accessory mounting pad and its associated cover. A section of the gasket separated and was displaced from its installed position. The FAA Airworthiness Inspector overseeing the examination reported that the installed gasket was intended to be used in conjunction with a hydraulic pump, if applicable, however, this particular engine configuration does not utilize a hydraulic pump, and therefore a hydraulic pump adapter pad gasket should have been installed. Personnel at the Challis airport reported that a large puddle of oil was found in the run-up area following the airplane's pre takeoff run-up and departure.
Probable cause
The installation of an improper oil gasket by maintenance personnel, which resulted in a loss of engine oil and subsequent loss of engine power during the emergency descent.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA05LA170
- Event ID
- 20050817X01270
- Case number
- SEA05LA170
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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, coordinates. 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: 98aab41f0e4b38ddafbd41e620d21826d5113116315d286555b9e07d85ddd418; retrieved 2026-09-21T09:04:13.881Z.