Airworthiness Directive · Amendment 39-15936 · Flight controls
Bombardier Model DHC-8-400 Series Airplanes
Superseded. A later AD replaced this one: AD 2010-01-06. Comply with the one in force.
This AD applies to Bombardier Model DHC-8-400, DHC-8-401, and DHC-8-402 airplanes, certificated in any category, serial numbers 4135 through 4149 inclusive.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
Unless already done, do the following actions.
(1) Within 30 days after the effective date of this AD, inspect the serial number of each of the six installed elevator PCUs having P/N 390600-1007. If one or more of the six installed elevator PCUs, P/N 390600-1007, have any of the PCU serial numbers 238, 698, 783 through 788 inclusive, 790, 793, 795, 802, 806, 807, 810, 820 through 823 inclusive, 826 through 828 inclusive, 831, 835, 838, 840, 886 through 889 inclusive, or 898 through 955 inclusive; without a suffix “A” after the serial number: Within 30 days after the effective date of this AD, perform a check for the correct operation of all installed elevator PCUs in accordance with the procedures detailed in Appendix A, B, or C of Bombardier Q400 All Operator Message 217B, dated April 26, 2007. Repeat the check thereafter before the first flight of each day until the replacement specified in paragraph (f)(3) of this AD is done. The checks in Appendix A and B of Bombardier Q400 All Operator Message 217B, dated April 26, 2007, must be performed by the flight crew, while the check specified in Appendix C of the all operators message must be performed by certificated maintenance personnel.
Note 1: Suffix “A” after the serial number indicates that the PCU has already passed a magnetic particle inspection and is cleared for continued use.
(2) If incorrect operation of any elevator PCU is found during any check required by paragraph (f)(1) of this AD, before further flight, replace the elevator PCU with a PCU, P/N 390600-1007, having a serial number not specified in paragraph (f)(1) of this AD; or with a PCU, P/N 390600-1007, having the suffix “A” after the serial number; in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-32, Revision A, dated January 18, 2008.
(3) Replacing all PCUs, P/N 390600-1007, having a serial number specified in paragraph (f)(1) of this AD, and not having suffix “A” after the serial number, with a PCU, P/N 390600-1007, having a serial number not specified in paragraph (f)(1) of this AD; or with a PCU, P/N 390600-1007, having the suffix “A” after the serial number; in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-32, Revision A, dated January 18, 2008; terminates the requirements of paragraph (f)(1) of this AD.
(4) Actions accomplished before the effective date of this AD according to Bombardier Service Bulletin 84-27-32, dated May 1, 2007, are considered acceptable for compliance with the corresponding action specified in this AD.
Note 2: This AD differs from the MCAI and/or service information as follows: Unlike the Canadian airworthiness directive CF-2009-16, dated April 20, 2009, this AD does not require the eventual replacement of all elevator PCUs identified in paragraph (f)(1) of this AD. The planned compliance times for those actions would allow enough time to provide notice and opportunity for prior public comment on the merits of those actions. Therefore, we are considering further rulemaking to address this issue.
