Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This proposed AD was prompted by chafing on high pressure fuel lines due to improper installation of an expandable pin on the lower cowl assembly. This proposed AD would require installing spring clips and repositioning the lanyard attachment points at the forward end and the forward firefloor of the lower cowl. We are proposing this AD to prevent chafing of the high pressure fuel lines, which if not corrected, could cause fuel leakage in a fire zone.