Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This proposal would require an inspection of the fuel tube assembly of the auxiliary power unit (APU) for clearance from adjacent components; and inspecting the fuel tube assembly and the bleed air duct shroud for discrepancies (insufficient clearance, nicks, dents, chafing, or other damage); and related investigative and corrective actions if necessary. This proposal also would require relocating certain support clamps on the APU fuel tube assembly. This action is necessary to prevent a fuel leak caused by chafing of the APU fuel tube assembly, which could result in fire in the center wing area. This action is intended to address the identified unsafe condition.