Airworthiness Directive · Amendment 39-18368 · Doors
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001 and subsequent.
We are adopting a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400 series airplanes. This AD was prompted by a report of several cracks found on the forward passenger airstair door step assembly. This AD requires an inspection to determine the serial number of the airstair door step assembly, and if necessary, an electronic tap test, reidentification of the airstair door step assembly, and replacement of the airstair door step assembly. We are issuing this AD to detect and correct cracks in the forward passenger airstair door step assembly; such cracking could propagate and result in the structural failure of the steps and impede the evacuation of passengers in the event of an emergency egress situation.
For airplanes having serial numbers 4001 through 4393: Within 320 days after the effective date of this AD, do an inspection to determine the serial number of the airstair door step assembly, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014, including Appendix A, and with the attached Short Brothers Service Bulletin D8400-52-0011, Revision C, dated February 26, 2014.
(1) If the serial number of the airstair door step assembly cannot be found, or if the serial number is illegible: Before further flight, do an electronic tap test to determine the existence of epoxy compound, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014, including Appendix A, and with the attached Short Brothers Service Bulletin D8400-52-0011, Revision C, dated February 26, 2014.
(i) If the existence of epoxy compound is confirmed, before further flight, reidentify the airstair door step assembly, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014, including Appendix A, and with the attached Short Brothers Service Bulletin D8400-52-0011, Revision C, dated February 26, 2014.
(ii) If the existence of epoxy compound is not confirmed: Within 6,000 flight hours after the effective date of this AD, replace the airstair door step assembly, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014, including Appendix A, and with the attached Short Brothers Service Bulletin D8400-52-0011, Revision C, dated February 26, 2014.
(2) If the serial number of the airstair door step assembly is in the affected range specified in paragraph 1.A., “Effectivity,” of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014: Within 6,000 flight hours after the effective date of this AD, replace the airstair door step assembly, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-52-77, Revision C, dated June 5, 2014, including Appendix A, and with the attached Short Brothers Service Bulletin D8400-52-0011, Revision C, dated February 26, 2014.
