Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-09-42
July 24, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
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.
Cessna service bulletins SEB09-6 and MEB09-3, initial release, dated May 11, 2009, specify the following:
An inspection to determine time-in-service for the switches.
Replacement of switches that
have been in service for four or more years with the month and year of
the installation written on the new replacement switch.
The month and year of the initial installation written on switches that have been in service for less than four years.
Recommendations
The FAA recommends that owners, operators, and maintenance
technicians do the actions of the above-referenced service bulletins
within the next 400 hours of operation, 12 months, or the next annual
inspection, whichever comes first.