Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-135BJ, -135ER, -135KE, -135KL, and -135LR Airplanes; and Model EMB-145, 145ER, -145MR, -145LR, -145XR, -145MP, and -145EP Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain EMBRAER airplanes listed above. This AD requires modifying the drain system of the auxiliary power unit (APU) by installing a scavenge pump and, for certain airplanes, replacing the APU exhaust assembly. This AD results from a report of fuel leaking from the APU feeding line and accumulating inside the APU compartment because the drain system is inadequate when the APU is running. We are issuing this AD to prevent fuel accumulation and subsequent flammable fuel vapors in the APU cowling, which, combined with an ignition source, could result in a fire or explosion.