Airworthiness Directives; Bombardier, Inc., Airplanes

We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc., Model BD-100-1A10 airplanes. This proposed AD was prompted by reports of fire incidents of the auxiliary power unit (APU) inlet, which caused tail cone damage after an initial failed APU start followed by two or more in-flight APU start attempts. This proposed AD would require modification of the APU electronic control unit (ECU) wiring harness. We are proposing this AD to address the unsafe condition on these products.