AD 2010-23-08

(a) This airworthiness directive (AD) becomes effective December 14, 2010.

(b) None.

(c) This AD applies to Bombardier, Inc. Model BD-700-1A10 and BD-700-1A11 airplanes, serial numbers 9002 and subsequent; certificated in any category.

(d) Air Transport Association (ATA) of America Code 24: Electrical power.

(e) The mandatory continuing airworthiness information (MCAI) states:

Following five reported cases of balance washer screw failure on similar RATs [ram air turbines]/air driven generators installed on other aircraft types, an investigation by Hamilton Sundstrand determined that a specific batch of the screws had a metallographic non-conformity that increased their susceptibility to brittle fracture. Subsequently, it was established that 187 RATs [Part Number (P/N) GL456-1101-7 and Hamilton Sundstrand P/Ns in the 762826 series] had non-conforming screws installed either during production or possibly during maintenance or repair at Hamilton Sundstrand repair stations.

Failure of a balance washer screw can result in loss of the related balance washer, with consequent turbine imbalance. Such imbalance could potentially result in RAT structural failure (including blade failure), loss of RAT electrical power and structural damage to the aircraft and, if deployment was activated by a dual engine shutdown, could also result in loss of hydraulic power for the flight controls [and consequent reduced ability of the flightcrew to maintain the safe flight and landing of the airplane].

This [Canadian] directive mandates checking of the RAT and replacing the balance washer screws, if required. It also prohibits future installation of unmodified RATs.

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

(g) For airplanes having serial numbers 9002 through 9380 inclusive: At the earliest of the times identified in paragraphs (g)(1), (g)(2), (g)(3) and (g)(4) of this AD, inspect to determine the serial number of the installed ram air turbine (RAT), in accordance with the Accomplishment Instructions of the applicable service bulletin listed in Table 1 of this AD. This inspection may be conducted visually, which requires lowering the RAT. A review of airplane maintenance records is acceptable in lieu of this inspection if the serial number of the RAT can be conclusively determined from that review.

(1) Within 500 flight hours or 24 months after the effective date of this AD, whichever occurs first; or

(2) Prior to the next in-flight or on-ground functional test of the RAT, whichever occurs first after the effective date of this AD; or

(3) Prior to the next in-flight or on-ground operational test of the RAT, whichever occurs first after the effective date of this AD; or

(4) Prior to the next scheduled RAT in-flight deployment.

(h) If the RAT serial number, as determined in paragraph (g) of this AD, is not listed in paragraph 1.A of the applicable service bulletin listed in Table 1 of this AD, no further action is required by this AD, except as required by paragraph (j) of this AD.

(i) If the RAT serial number, determined in paragraph (g) of this AD, is listed in paragraph 1.A. of the applicable service bulletin listed in Table 1 of this AD, before further flight, inspect to determine if the symbol “24-7” is marked on the RAT identification plate, in accordance with the Accomplishment Instructions of the applicable service bulletin listed in Table 1 of this AD. A review of airplane maintenance records is acceptable in lieu of this inspection if the symbol “24-7” mark can be conclusively determined from that review.

(1) If the symbol “24-7” is marked on the RAT identification plate, the balance washer screws have already been replaced and no further action is required by this AD, except as required by paragraph (j) of this AD.

(2) If the symbol “24-7” is not marked on the RAT identification plate, before further flight, replace all balance washer screws with new balance washer screws, part number MS24667-14, and mark the RAT identification plate with the symbol “24-7,” in accordance with the Accomplishment Instructions of the applicable service bulletin listed in Table 1 of this AD.

(j) For all airplanes: As of the effective date of this AD, no person may install on any airplane a replacement or spare RAT (P/N GL456-1101-7; Hamilton Sundstrand P/Ns in the 762826 series) having one of the S/Ns listed in paragraph 1.A. of the applicable service bulletin listed in Table 1 of this AD unless the balance washer screws have already been replaced and the symbol “24-7” is marked on the RAT identification plate.

(k) Actions accomplished before the effective date of this AD, in accordance with the applicable service bulletin listed in Table 2 of this AD, are considered acceptable for compliance with the corresponding action specified in this AD.

Note 1:

This AD differs from the MCAI and/or service information as follows: Although Canadian Airworthiness Directive CF-2010-01, dated January 18, 2010, recommends accomplishing the visual inspection prior to the next scheduled in-flight operational test of the RAT, we have determined that interval would not address the identified unsafe condition soon enough to ensure an adequate level of safety for the affected fleet in light of the degree of urgency associated with the subject unsafe condition. This difference has been coordinated with Transport Canada Civil Aviation (TCCA).

(l) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York, 11590; telephone 516-228-7300; fax 516-794-5531. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

(m) Refer to MCAI TCCA Airworthiness Directive CF-2010-01, dated January 18, 2010; and Bombardier Service Bulletins 700-24-075, Revision 02, dated March 15, 2010, and 700-1A11-24-014, Revision 02, dated March 15, 2010; for related information.

(n) You must use Bombardier Service Bulletins 700-24-075, Revision 02, dated March 15, 2010; or Bombardier Service Bulletin 700-1A11-24-014, Revision 02, dated March 15, 2010; as applicable; to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Bombardier, Inc., 400 Côte-Vertu Road West, Dorval, Québec H4S 1Y9, Canada; telephone 514-855-5000; fax 514-855-7401; e-mail thd.crj@aero.bombardier.com; Internet http://www.bombardier.com.

(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.