SEA98IA044 · Mooney M20K
Mooney M20K · Incident: loss of engine power en route
From Sacramento Executive Airport (SAC) to King County International Airport - Boeing Field (BFI)
Event
- NTSB case
- SEA98IA044
- 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
- Incident
- 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
Mooney M20K
- 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
- N3556H
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Sacramento Executive Airport (SAC), Sacramento, CATo King County International Airport - Boeing Field (BFI), Seattle, WA
- 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 · 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
- Loss of engine power
- 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
- Fuel starvation
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Fluid, fuel › Starvation
- Fuel system, tank › Contamination, water
- Pilot in command › Aircraft preflight, inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the aircraft was parked outdoors during the winter months, and it was not flown much. He flew the airplane 3 days prior to the accident flight. During that preflight he reported, 'a puddle of water (smell & taste tested) under the aircraft low point - unusual because the tarmac was dry.' He 'drained the fuel lines using the gascolator without testing, but tested all four tanks.' He stated that the right tanks tested fine but he found 'an estimated total of a gallon of water from the two left tanks.' The flight with a fuel stop was uneventful. On the day of the accident, he pre-flighted the aircraft and 'drained about 1/2 cup of water from the left side'. The first leg of the trip was flown at 12,000 feet MSL, and he refueled. The aircraft then departed, and the flight was cleared to climb to flight level 240. He reported the outside air temperature as -27 degrees Celsius. Shortly thereafter, he noticed a little engine roughness. He executed a number of trouble shooting procedures attempting to correct the problem without success. Approximately 5-7 miles from the airport the engine ceased developing power. He then executed a forced landing under dark night conditions to an unlighted landing site. He stated that 'in the end, I just descended into total blackness.' Examination of the airplane after the accident by an FAA Inspector revealed several ounces of water drained from the left wing tank. No anomalies were noted that would have precluded operation.
Probable cause
The pilot's inadequate preflight which failed to detect water contaminated fuel that subsequently led to fuel icing at altitude, blockage of fuel lines which resulted in fuel starvation. A related factor was the dark night conditions.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA98IA044
- Event ID
- 20001211X09777
- Case number
- SEA98IA044
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1998-03-12.
- API snapshot SHA-256: 69883ceb456caae8f326e3d73f95c405e7490b5a0aa3b8d4941ea8f852cd4f7c; retrieved 2026-09-22T17:59:07.621Z.