SEA98LA190 · Cessna 150L
Cessna 150L · Accident: loss of engine power during initial climb
From 65S to an unrecorded destination
Event
- NTSB case
- SEA98LA190
- 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
Cessna 150L
- Aircraft type
- Cessna 150
- 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
- N19427
- Operator
- Jacobson, Sandra, L. · private individual
- Onboard fatalities
- Unknown
- Route
- From 65STo not recorded
- 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
- Loss of engine power
- 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, other › Fatigue
- Engine assembly, other › Scored
- Other maintenance personnel › Maintenance, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During the initial climb following a touch-and-go landing, the engine sputtered twice and the pilot-in-command initiated an emergency landing. The field of choice was obstructed with construction equipment and she chose an alternate field. She retarded the throttle to idle, lowered full flaps, and slipped the aircraft to land as expeditiously as possible; and then steered the aircraft into small trees and brush to avoid going over an embankment. Post-crash examination revealed all 3 bosses of the #3 cylinder broken, thus rendering the intake/exhaust valves permanently closed. Metallurgical examination revealed that the separation of the rocker arm shaft bosses was initiated by fatigue cracking in the boss located adjacent to the exhaust valve. Further examination revealed the presence of heavy tool marks on the bore surface of all three bosses. The heavy manual cutting of the bore surface is not authorized by the engine manufacturer and the surface created by this procedure did not meet the engine manufacturer requirements for surface finish in the bore of the bosses. A review of the aircraft's engine log revealed an overhaul 645.4 hours previous to the accident. The overhaul facility reported that all 4 cylinders were outsourced during the overhaul procedure.
Probable cause
Improper maintenance by an outsourcing facility which resulted in a lack of identification of scoring of the interior of the #3 cylinder rocker shaft bosses. The scoring resulted in a fatigue fracture and subsequent permanent closure of both intake and exhaust valves. Contributing factors were the lack of a suitable landing site and trees.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA98LA190
- Event ID
- 20001211X11180
- Case number
- SEA98LA190
- 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. 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: 378dfe729c754cbe1020f573f8d4645f3135730719f7ec1f6d0d80e54e516f33; retrieved 2026-09-22T16:37:30.034Z.