AD FAA-2018-0547

The FAA is withdrawing a notice of proposed rulemaking (NPRM) that proposed to adopt a new airworthiness directive (AD) that would have applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. The NPRM was prompted by reports of wear on fuel couplings, bonding springs, and sleeves as well as fuel tube end ferrules and fuel component end ferrules. The NPRM would have required repetitive inspections of the existing clamshell coupling bonding wires, fuel couplings, and associated sleeves for certain criteria, and replacement as necessary. The NPRM would also have required repetitive inspections of the fuel tube end ferrules, fuel component end ferrules, and ferrule o-ring flanges for damage and wear, and rework as necessary. Since issuance of the NPRM, the FAA determined that more restrictive airworthiness limitations are also necessary, that an optional terminating modification is appropriate for certain airplanes, and that the NPRM does not adequately address the identified unsafe condition. Accordingly, the NPRM is withdrawn.