Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain The Cessna Aircraft Company (Cessna) Models 401, 401A, 401B, 402, 402A, 402B, 402C, 404, 411, 411A, 414, 414A, 421, 421A, 421B, 421C, 425, and 441 airplanes equipped with certain avionics bus circuit breaker switches. This proposed AD would require you to inspect the avionics bus circuit breaker switch to determine the date code and replace any without a date code. This proposed AD would also impose a 1,000-hour safe life limit on avionics bus circuit breaker switches with a date code earlier than 0434. This proposed AD results from reports of smoke and a burning smell in the cockpit. We are issuing this proposed AD to prevent failure of the avionics bus circuit breaker switch, which could result in smoke and a burning smell in the cockpit. This failure could lead to reduced ability to control the airplane.