Probable cause
The loss of engine power during cruise due to the separation of the spark plug because of the loose threads. Contributing to the accident was trees.
NTSB analysis
The pilot reported that during cruise flight, about 700 feet above the ground, the engine lost power. He stated that he attempted to troubleshoot the power loss to no avail. He then selected a landing site, but did not have sufficient altitude and landed the airplane in trees. The airplane came to rest in the tree tops and had sustained substantial damage due to the impact with the trees. Examination of the engine subsequent to the accident revealed that the spark plug had fallen out of its threaded hole. Examination of the threads revealed that they were loose and had been re-cut at some time in the past.
Text from the NTSB. Open the NTSB docket for CHI08CA114 for the full record.
Event
- Date
- Apr 4, 2008
- Type
- Accident
- Place
- Pulaski, Wisconsin
- Highest injury
- Minor
- Minor injuries
- 1
- Weather
- Visual (VMC)
- Light
- Day
QUAD CITY ULTRALIGHT
- N-number
- N423V
- 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.