Cessna Landing Light, Beacon Light, and Taxi Light switches on Cessna 100, 200, and 300 series airplanes SAIB CE-09-42

This Special Airworthiness Information Bulletin (SAIB) is being issued to advise you of an airworthiness concern on mandatory replacement intervals of Cessna Landing Light, Beacon Light, and Taxi Light switches on Cessna 100, 200, and 300 series airplanes specified per Cessna service bulletins MEB09-3 and SEB09-6 dated May 11, 2009.
At this time, this airworthiness concern is not considered an unsafe condition that would warrant an airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR part 39).

Background
Cessna 100, 200, and 300 series airplanes utilize switches in the Landing Light, Beacon Light, and Taxi Light circuits that have been reported failing in the field causing overheating and smoke in the cockpit. There have been reports of burned insulation on the wiring terminals to the switch. On at least one occasion, there was a small fire in the cockpit. The failure in these applications can be attributed to contact erosion leading to irregular arcing and eventual failure of the switch. The contact erosion has been shown to occur after approximately 4,000 cycles of operation.

SAIB Attached