SEA03LA176 · Mooney M20D
Mooney M20D · Accident: partial loss of engine power (mechanical failure) during initial climb
From Ken Jernstedt Airfield (4S2) to Eugene Airport (EUG)
Event
- NTSB case
- SEA03LA176
- 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
Mooney M20D
- Aircraft type
- Mooney M20
- 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
- N6619U
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Ken Jernstedt Airfield (4S2), Hood River, ORTo Eugene Airport (EUG), Eugene, OR
- 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
- Initial climb
- 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
- Partial loss of engine power (mechanical failure)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- 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
- Engine assembly, cylinder › Low compression
- Engine assembly, valve, intake › Leak
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's father (right seat), a commercial pilot with more than 2,000 hours in the accident aircraft, reported that the engine ran smoothly on the ground and an RPM check prior to takeoff yielded 2600 RPM. The takeoff roll on the 3,040-foot long asphalt runway seemed long with less than normal power to the flying pilot (left seat). The aircraft was rotated at 65 knots but settled back to the runway at which time the right seat pilot took control and established a shallow climb rate toward the rising terrain west of the airport. Both pilots felt that an aborted takeoff would result in an overrun into a grassy area containing vehicles and pedestrians. The flying pilot (right seat) then banked to avoid a large tree and the aircraft settled into the treetops eventually coming to rest inverted in a bog. Post-crash examination and test run of the engine revealed that the number one cylinder could develop no more than 25-35 pounds of compression. Further examination revealed the number one cylinder intake seat had dropped down out of its normally seated position at an angle preventing the valve from seating evenly during the compression stroke.
Probable cause
A power loss due to a mis-seated intake valve on the #1 cylinder resulting in leakage during the compression stroke and low compression. Contributing factors were the rising terrain and trees.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA03LA176
- Event ID
- 20030903X01447
- Case number
- SEA03LA176
- 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: db3ce0ff18f6312124a71126e1d3bb6a24a0cdf0259e5a84847642f2eb1a7e33; retrieved 2026-09-21T19:23:10.164Z.