E8-25637. Airworthiness Directives; Bombardier Model CL-600-2C10 (Regional Jet Series 700 & 701) Series Airplanes and Model CL-600-2D24 (Regional Jet Series 900) Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

The FAA is revising an existing airworthiness directive (AD) that applies to certain Bombardier Model CL-600-2C10 (Regional Jet series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet series 900) series airplanes. That AD currently requires revising the Airworthiness Limitations section of the Instructions of Continued Airworthiness by incorporating new repetitive inspections and an optional terminating action for the repetitive inspections, and repairing any crack. This new AD clarifies the applicability of the existing AD. This AD results from reports of hydraulic pressure loss in either the number 1 or number 2 hydraulic system due to breakage or leakage of hydraulic lines in the aft equipment bay and reports of cracks on the aft pressure bulkhead web around the feed-through holes. We are issuing this AD to prevent loss of hydraulic pressure, which could result in reduced controllability of the airplane, and to detect and correct cracks on the aft pressure bulkhead web, which could result in reduced structural integrity of the aft pressure bulkhead.

DATES:

This AD is effective December 3, 2008.

On July 27, 2005 (70 FR 35987, June 22, 2005), the Director of the Federal Register approved the incorporation by reference of Bombardier CRJ 700/900 Series Temporary Revision MRM2-129, dated June 1, 2004.

ADDRESSES:

For service information identified in this AD, contact Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone [phone]) is the Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Pong Lee, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

The FAA proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with an airworthiness directive (AD) to revise AD 2005-13-02, amendment 39-14138 (70 FR 35987, June 22, 2005). The existing AD applies to certain Bombardier Model CL-600-2C10 (Regional Jet series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet series 900) series airplanes. The proposed AD was published in the Federal Register on May 19, 2008 (73 FR 28754) to continue to revise the Airworthiness Limitations section of the Instructions of Continued Airworthiness by incorporating new repetitive inspections and an optional terminating action for the repetitive inspections, and repairing any crack. The proposed AD also clarifies the applicability of the existing AD.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Request To Withdraw NPRM

Comair requests that the NPRM be withdrawn. Comair states that the minor editorial correction to the Applicability section of the NPRM should not warrant a revised or new directive, and that the revised AD will not increase the airworthiness of any airplane. Comair also states that a review of the airplane log will indicate which service bulletins have been incorporated by Bombardier, on a limited basis, before delivery to a customer.

We do not agree with Comair to withdraw the NPRM. When a previously issued AD is changed, we issue a correction, revision, or supersedure AD, depending on the nature of the material being changed. In the case of this AD, a revision AD is the appropriate means to clarify the Applicability section of AD 2005-13-02. We have determined that issuance of this AD is necessary because Bombardier does not incorporate service bulletins in production and operators may misinterpret which affected airplanes are subject to the requirements of this AD.

Requests To Revise the Applicability Section

Comair notes that Bombardier Service Bulletin 670BA-29-008 is currently at Revision B, dated August 28, 2007. Paragraph (c) of the NPRM (i.e., Applicability section) refers to the initial issue, dated March 12, 2004; and Revision A, dated May 5, 2004; of that service bulletin.

From this comment, we infer that Comair is requesting that paragraph (c) of the NPRM be revised to also exclude those airplanes on which Revision B of Bombardier Service Bulletin 670BA-29-008 has been incorporated. We agree and revised paragraph (c) of this AD accordingly.

Comair requests that the serial numbers for Model CL-600-2C10 series airplanes identified in Table 1 of the NPRM be limited to serial numbers 10003 through 10156 inclusive. Comair states that comments were submitted to the NPRM for AD 2005-13-02 to limit the serial number range for which that AD should apply. In the preamble of the final rule for AD 2005-13-02, Comair notes that the FAA agreed with that comment but believes that we made a mistake by not revising the serial numbers in Table 1 of that AD (which is retained in the NPRM). Although not addressed in its NPRM comment for AD 2005-13-02, Comair also requests that, for the reason discussed previously, Table 1 of the NPRM be limited to serial numbers 15001 through 15026 inclusive for Model CL-600-2D24 series airplanes. Comair states that it does not make sense to issue an AD against airplane serial numbers for which there is no action required.

We do not agree with Comair's request to revise Table 1 of this AD. As stated in the preamble of AD 2005-13-02, we revised the applicability of that AD to exclude those airplanes on which certain modification summaries and service information had been incorporated. This approach rather than changing the reference to certain serial numbers, accomplishes the same intent. The referenced modification summaries and service information in this AD (i.e., Modification Summaries 670T00494 or 670T11944; Modification Summary 670T11508; and Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004, Revision A, dated May 5, 2004, or Revision B, dated August 28, 2007) identify the serial numbers of those airplanes. Therefore, we find no change to this AD is necessary in this regard.

Request To Revise Costs of Compliance Section

Comair requests that the number of U.S.-registered airplanes specified in the Costs of Compliance section of the NPRM be changed from 116 to 255. Comair states that the Costs of Compliance section takes into account that either only airplanes with serial numbers below 10157 and 15027 are affected by this AD or the number needs to be adjusted to today's U.S. registry level. Comair states that a conversation with a Bombardier Field Service Representative indicates that all affected serial numbers have had the modification summaries and/or service bulletin specified in paragraph (c) of the NPRM incorporated and thus the NPRM does not apply to any U.S registered airplanes.

We agree with Comair to revise the Costs of Compliance section of this AD to reflect the current number of affected airplanes on the U.S. registry (i.e., 324 airplanes). We consulted with Bombardier and confirmed that all affected Bombardier Model CL-600-2C10 (Regional Jet series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet series 900) series airplanes have been modified according to the optional terminating action specified in this AD. Therefore, currently, this AD imposes no additional financial burden on any U.S. operator. We have also revised the Costs of Compliance section of this AD in this regard.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

This AD affects about 324 airplanes of U.S. registry. We have been advised that all affected Bombardier Model CL-600-2C10 (Regional Jet series 700 & 701) series airplanes and Model CL-600-2D24 (Regional Jet series 900) series airplanes on the U.S. Register have been modified according to the optional terminating action specified in this AD. Therefore, currently, this AD imposes no additional financial burden on any U.S. operator.

However, if an unmodified airplane is imported and placed on the U.S. Register in the future, the actions required by this AD would take about 1 work hour per airplane, at an average labor rate of $80 per work hour. Based on these figures, we estimate the cost of this AD to be $80 per airplane.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by removing amendment 39-14138 ( 70 FR 35987, June 22, 2005) and adding the following new airworthiness directive (AD):

2005-13-02 Bombardier, Inc. (Formerly Canadair): Amendment 39-15705. Docket No. FAA-2008-0555; Directorate Identifier 2008-NM-074-AD.

Effective Date

(a) This airworthiness directive (AD) is effective December 3, 2008.

Affected ADs

(b) This AD revises AD 2005-13-02.

Applicability

(c) This AD applies to the airplanes listed in Table 1 of this AD, certificated in any category, excluding those airplanes on which Modification Summary 670T00494 or 670T11944; and Modification Summary 670T11508 or Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004, Revision A, dated May 5, 2004, or Revision B, dated August 28, 2007; has been incorporated.

Table 1—Applicability

Bombardier model	Serial No.
(1) CL-600-2C10 (Regional Jet Series 700 & 701) series airplanes	10003 through 10999 inclusive.
(2) CL-600-2D24 (Regional Jet Series 900) series airplanes	15001 through 15990 inclusive.

Unsafe Condition

(d) This AD resulted from reports of hydraulic pressure loss in either the number 1 or number 2 hydraulic system due to breakage or leakage of hydraulic lines in the aft equipment bay and reports of cracks on the aft pressure bulkhead web around the feed-through holes. We are issuing this AD to prevent loss of hydraulic pressure, which could result in reduced controllability of the airplane, and to detect and correct cracks on the aft pressure bulkhead web, which could result in reduced structural integrity of the aft pressure bulkhead.

Compliance

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

Restatement of Requirements of AD 2005-13-02

Revision of Airworthiness Limitations Section

(f) Within 30 days after July 27, 2005 (the effective date of AD 2005-13-02), revise the Airworthiness Limitations section of the Instructions of Continued Airworthiness by inserting a copy of the new repetitive inspections and an optional terminating action of Bombardier CRJ 700/900 Series Temporary Revision (TR) MRM2-129, dated June 1, 2004, into section 1.4, Part 2 (Airworthiness Limitations), of Bombardier Regional Jet Model CL-600-2C10 and CL-600-2D24 Maintenance Requirements Manual, CSP B-053. Thereafter, except as provided in paragraph (h)(2) or (i) of this AD, no alternative structural inspection intervals may be approved for this aft pressure bulkhead and pylon pressure pan in the vicinity of the hydraulic fittings and the hydraulic tube adapters.

(g) When the information in TR MRM2-129, dated June 1, 2004, is included in the general revisions of the Maintenance Requirement Manual, the general revisions may be inserted into the Airworthiness Limitations section of the Instructions of Continued Airworthiness and this TR may be removed.

Corrective Action

(h) If any crack is found during any inspection done in accordance with Bombardier CRJ 700/900 Series TR MRM2-129, dated June 1, 2004, or the same inspection specified in the general revisions of the Maintenance Requirement Manual, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD.

(1) Before further flight, repair the crack in accordance with a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent).

(2) At the applicable time specified in paragraph (h)(2)(i) or (h)(2)(ii) of this AD, revise the Airworthiness Limitations section of the Instructions of Continued Airworthiness by inserting a copy of the inspection requirements for the repair required by paragraph (h)(1) of this AD into Section 1.4, Part 2 (Airworthiness Limitations), of Bombardier Regional Jet Model CL-600-2C10 and CL-600-2D24 Maintenance Requirements Manual, CSP B-053. Thereafter, except as provided in paragraph (i) of this AD, no alternative structural inspection intervals may be approved for this aft pressure bulkhead and pylon pressure pan in the vicinity of the hydraulic fittings, and the hydraulic tube adapters.

(i) If the repair required by paragraph (h)(1) of this AD is done after the effective date of this AD: Revise the Airworthiness Limitations section within 12 months after the repair.

(ii) If the repair required by paragraph (h)(1) of this AD was accomplished before July 27, 2005: Revise the Airworthiness Limitations section within 12 months after the repair or 30 days after July 27, 2005, whichever occurs later.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, New York ACO, FAA, ATTN: Pong Lee, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone [phone]; fax [phone]; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Related Information

(j) Canadian airworthiness directive CF-2004-14, dated July 20, 2004, also addresses the subject of this AD.

Material Incorporated by Reference

(k) You must use Bombardier CRJ 700/900 Series Temporary Revision MRM2-129, dated June 1, 2004, to perform the actions that are required by this AD, unless the AD specifies otherwise.

(1) On July 27, 2005 (70 FR 35987, June 22, 2005), the Director of the Federal Register approved the incorporation by reference of Bombardier CRJ 700/900 Series Temporary Revision MRM2-129, dated June 1, 2004.

(2) Contact Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada, for a copy of this service information. You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on October 9, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.