Probable cause
A partial loss of engine power due to the rear cylinder's spark plug coming out of the cylinder head.
NTSB analysis
According to the sport pilot, during cruise flight in his experimental light sport airplane he noted that the two-cylinder engine's cylinder head and exhaust gas temperature gauges decreased in temperature. Thereafter, the number 1 cylinder (rear) stopped producing power, and engine power was partially lost. The pilot made a forced landing on upsloping, rough terrain. During landing, the airplane's forward fuselage buckled. The pilot said that examination of the engine revealed that the spark plug had come out of the engine's rear cylinder head. The pilot had changed the spark plugs about 2.5 hours prior to the mishap.
Text from the NTSB. Open the NTSB docket for WPR09CA091 for the full record.
Event
- Date
- Jan 18, 2009
- Type
- Accident
- Place
- Santa Ynez, California
- Nearest airport
- Santa Ynez (IZA)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
EARTHSTAR
- N-number
- N532JS
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.