Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes, and Model DHC-8-200 and -300 series airplanes. This proposed AD was prompted by a report of heat damage found on a nacelle firewall after an unsuccessful engine ground start and several events of heat damage found on direct current starter/generator terminal block assemblies. This proposed AD would require an inspection for damage on the nacelle firewalls and the terminal block assemblies and to make sure the insulating sleeves are installed and have no damage, and corrective action if necessary. We are proposing this AD to prevent arcing between the firewall and terminal blocks that are missing insulating sleeves on the conductive bushings, which could, in combination with a fuel or hydraulic fluid leak, be an ignition source for a fire.