Airworthiness Directives; British Aerospace Model BAe 146-100A, - 200A, and -300A Airplanes and Model Avro 146-RJ70A, -RJ85A, and RJ-100A Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain British Aerospace Model BAe 146-100A, -200A, and -300A airplanes and Model Avro 146-RJ70A, -RJ85A, and RJ-100A airplanes. This action requires inspections to detect cracking and evidence of exhaust leaks in the forward face of the central panel of the forward firewall of the auxiliary power unit (APU) bay, and replacement of the central panel with a new panel, if necessary. This amendment is prompted by a report indicating that cracking due to leakage of hot exhaust gases was found in the forward face of the forward firewall of the APU bay. The actions specified in this AD are intended to prevent such gas leakage and subsequent cracking, which could damage the wiring to the APU fire bottle; this condition could result in failure of the APU fire bottle to discharge in the event of an APU fire.