Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 757-200 series airplanes. This proposed AD would require modifying the frequency converters located in the closet assembly in the passenger compartment, and making various wiring changes in and between the closet assembly and forward purser work station. This proposed AD also would require modifying the in-flight entertainment system prior to or concurrently with the modification of the frequency converters. This proposed AD is prompted by a certification review that revealed a frequency converter failure mode not identified in the original system design. We are proposing this AD to prevent a short circuit between the frequency converter output and the distribution circuit breakers, which could result in overheating and failure of adjacent wiring and consequent degraded operation of airplane systems.