05-12000. 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 adopting a new airworthiness directive (AD) for certain Bombardier Model CL-600-2C10 (Regional Jet series 700 & 701) series airplanes, and Model CL-600-2D24 (Regional Jet series 900) series airplanes. This AD 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 AD is prompted by 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 these 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 becomes effective July 27, 2005.

The incorporation by reference of a certain publication listed in the AD is approved by the Director of the Federal Register as of July 27, 2005.

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.

Docket: The AD docket contains the proposed AD, comments, and any final disposition. You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Washington, DC. This docket number is FAA-2004-19754; the directorate identifier for this docket is 2004-NM-181-AD.

FOR FURTHER INFORMATION CONTACT:

Serge Napoleon, 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:

The FAA proposed to amend 14 CFR part 39 with an AD for 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 action, published in the Federal Register on December 1, 2004 (69 FR 69842), proposed to require 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.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD.

Request To Remove Airplanes From the Applicability

One commenter requests that certain airplane serial numbers be excluded from the applicability specified in paragraph (c) of the proposed AD. The commenter states that the inspection of the hydraulic tube adapters specified in Bombardier CRJ 700/900 Series Temporary Revision (TR) MRM2-129, dated June 1, 2004 (referenced in the proposed AD as the appropriate source of service information), should be applicable to Bombardier Model CL-600-2C10 (Regional Jet Series 700 & 701) series airplanes having serial numbers 10003 through 10099 inclusive, since Modification Summary 670T11944 was introduced in production at serial number 10100. The commenter also states the two remaining inspections of the bulkhead assembly and pylon pressure pan specified in TR MRM2-129 should be applicable to only airplanes having serial numbers 10003 through 10156 inclusive, since Modification Summary 670T11508 was incorporated in production at serial number 10157.

We agree. Bombardier CRJ 700/900 Series MRM2-129, dated June 1, 2004, identifies Modification Summaries 670T00494 or 670T11944; and Modification Summary 670T11508 or Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004, or Revision A, dated May 5, 2004; as terminating modification for the applicable repetitive inspections. Therefore, we have revised the applicability of this AD to “exclud[e] those airplanes on which Modification Summaries 670T00494 or 670T11944; and Modification Summary 670T11508 or Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004, or Revision A, dated May 5, 2004); has been incorporated in production.”

Request To Refer to Latest Revision of Maintenance Requirement Manual

One commenter requests that paragraph (f) of the proposed AD refer to Revision 4, dated September 9, 2004, of the general revisions of the Maintenance Requirement Manual instead of Bombardier CRJ 700/900 Series TR MRM2-129, dated June 1, 2004. The commenter states that TR MRM2-129 was superseded by Revision 4 of the general revisions before publication of the NPRM in the Federal Register.

We contacted the commenter to get clarification about its request. In an e-mail response, the commenter states that its Maintenance Requirement Manual no longer contains TR MRM2-129, because it has been superseded by Revision 4 of the general revisions. The commenter also states that there are differences between the two documents and provides an example of such a difference.

We do not agree with the commenter's request to revise paragraph (f) of the AD. We acknowledge that, once TR MRM2-129 is incorporated into the general revisions of the Maintenance Requirement Manual, it is void and no longer exists. It is impossible for us to ascertain the revision level of the general revisions at which the contents of a TR will be incorporated and to anticipate when that will be done. Therefore, we find it appropriate to refer to TR MRM2-129 in paragraph (f) of the AD. It should be noted that we attempted to address incorporation of the contents of TR MRM2-129 into the general revisions in paragraph (h) of the proposed AD, which states, “When the information in TR MRM2-129, dated June 1, 2004, is included in the general revisions of the Maintenance Requirement Manual, this TR may be removed.” However, we find that clarification is necessary and have revised paragraph (h) to read “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.”

Request To Revise Compliance Time for Paragraph (h)(2) of the NPRM

One commenter requests that a subparagraph be added to paragraph (h) of the proposed AD stating, “Within 30 days after the effective date of this AD for cracks previously repaired revise the Airworthiness Limitations section of the Maintenance Requirement Manual as stated in (h)(2).” The commenter notes that paragraph (h) of the proposed AD does not address airplanes that were previously repaired.

A second commenter requests that paragraph (h)(2) of the proposed AD be extended from “Within 30 days after repairing any crack * * *” to “Within 30 days after receiving any new inspection requirements for repairs * * *.” The commenter states that it has experienced cases where the airplane manufacturer has exceeded 12 months for damage tolerance evaluations of its repairs.

We agree with the first commenter that paragraph (h)(2) of the proposed AD does not address airplanes that have been repaired before the effective date of this AD. The specified compliance time of “within 30 days after repairing any crack in accordance with paragraph (h)(1) of this AD” would ground those airplanes on the effective of this AD. We also agree with the second commenter to extend the compliance time of paragraph (h)(2) of the AD, but do not agree with the commenter's suggested compliance time. We have determined that the new inspection requirements are not always readily available after a repair. We have consulted with TCCA and determined that a 12-month compliance time is an adequate amount of time for operators to incorporate the new inspection criteria. Therefore, we have revised paragraph (h)(2) of the AD by including two new subparagraphs for the revised compliance time. The revised compliance time is as follows:

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

Conclusion

We have carefully reviewed the available data, including the comments that have been submitted, 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 will affect about 116 airplanes of U.S. registry. The required actions will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $7,540, or $65 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. 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

2005-13-02 Bombardier, Inc. (Formerly Canadair): Amendment 39-14138. Docket No. FAA-2004-19754; Directorate Identifier 2004-NM-181-AD.

Effective Date

(a) This AD becomes effective July 27, 2005.

Affected ADs

(b) None.

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 Summaries 670T00494 or 670T11944; and Modification Summary 670T11508 or Bombardier Service Bulletin 670BA-29-008, dated March 12, 2004, or Revision A, dated May 5, 2004; has been incorporated in production.

Table 1.—Applicability

Bombardier model	Serial numbers
(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 was prompted by 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 these 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.

Revision of Airworthiness Limitations Section

(f) Within 30 days after the effective date of this AD, 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 the effective date of this AD: Revise the Airworthiness Limitations section within 12 months after the repair or 30 days after the effective date of this AD, whichever occurs later.

Alternative Methods of Compliance (AMOCs)

(i) The Manager, New York ACO, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

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. The Director of the Federal Register approves the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, contact Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. To view the AD docket, contact the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal _regulations/ibr_locations.html.

Issued in Renton, Washington, on June 10, 2005.

Michael Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.