Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model BD-100-1A10 (Challenger 300) airplanes. This proposed AD was prompted by multiple reports of chafing found on an electrical wiring harness in the aft equipment bay, caused by contact between the wiring harness and a neighboring hydraulic line. This proposed AD would require an inspection, repair if necessary, and modification of the wiring harness installation to ensure that the wiring harness routing is correct and a minimum clearance between the wire and the hydraulic line is maintained. We are proposing this AD to detect and correct chafing on an electrical wiring harness, which could cause an electrical short circuit or lead to a malfunction of the flight control system, the engine indication system, or the hydraulic power control system, and adversely affect the continued safe operation and landing of the airplane.