04-13224. Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This proposal would require a one-time inspection of the shafts of the main landing gear (MLG) side-brace fittings to detect corrosion, and the forward and aft bushings in the left-hand and right-hand MLG side-brace fittings to detect discrepancies. This proposal also would require corrective and related actions if necessary. This action is necessary to prevent fractures of the MLG side-brace fitting shafts, and possible collapse of the MLG. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by July 14, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-11-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-11-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New York.

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:

 

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-11-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-11-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. TCCA advises that there have been reports of fractures of the side-brace fitting shafts of the main landing gear (MLG). The fractures occurred on Bombardier Model CL-604 series airplanes. Investigation revealed that the fractures were caused by corrosion on the forward side of the MLG side-brace fitting shafts. Fractures of the side-brace fitting shafts, if not corrected, could result in collapse of the MLG.

The subject area on the affected Bombardier Model CL-604 series airplanes is almost identical to that on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. Therefore, Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes may be subject to the same unsafe condition revealed on the Bombardier Model CL-604 series airplanes. The Model CL-604 series airplanes are the business version of the Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. The FAA may consider issuing further rulemaking for the affected Model CL-604 series airplanes.

Explanation of Relevant Service Information

Bombardier has issued Service Bulletin 601R-57-036, Revision ‘C’, including Appendix A, dated January 30, 2003, which describes procedures for a visual inspection of the shafts of the side-brace fittings of the MLG for corrosion; and a visual inspection of the forward and aft bushings in the MLG side-brace fittings for discrepancies (gouges, scores, corrosion, or other damage). If corrosion is found on the MLG side-brace fitting shaft, the corrective action is to replace the side-brace fitting shaft with a new or serviceable shaft. The service bulletin specifies that operators should complete a report detailing the extent of the corrosion, and send it to the manufacturer. If the forward and aft bushings in the MLG side-brace have any discrepancy, the corrective action is to contact Bombardier for replacement instructions.

Following the inspection and any necessary corrective actions, the service bulletin describes related actions that include reconnecting the MLG side-brace fitting; installing a new improved nut having a new part number; and performing a functional test of the MLG extension/retraction system.

TCCA classified this service bulletin as mandatory and issued Canadian airworthiness directive CF-2002-41, dated September 20, 2002, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, TCCA has kept us informed of the situation described above. We have examined the findings of TCCA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Differences Among the Proposed AD, the Service Bulletin, and the Canadian Airworthiness Directive

Although the Canadian airworthiness directive and the service bulletin specify that operators may contact Bombardier for certain replacement instructions, this proposed AD would require operators to replace per a method approved by either the FAA or the TCCA (or its delegated agent). In light of the type of replacement that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a replacement approved by either the FAA or the TCCA would be acceptable for compliance with this proposed AD.

The Canadian airworthiness directive mandates, and the Bombardier service bulletin recommends, compliance at the next scheduled “C-check,” but no later than June 30, 2004. Because “C-check” schedules vary among operators, this proposed AD would require compliance within 4,000 flight cycles or 20 months after the effective date of this AD, whichever occurs first. We find that 4,000 flight cycles or 20 months is appropriate for affected airplanes to continue to operate without compromising safety.

Although the Canadian airworthiness directive refers to an inspection of the bore surface of the bushing for roughness, this proposed AD would not include this inspection. This inspection was removed from Revision ‘C’ of Bombardier Service Bulletin 601R-57-036, which is the source of service information for the actions in this proposed AD.

The Canadian airworthiness directive does not include the functional test of the MLG extension/retraction system as part of the corrective actions. However, this test is included in Revision ‘C’ of Bombardier Service Bulletin 601R-57-036. Therefore, this proposed AD would include this test as part of the related actions following any necessary replacement of a side-brace fitting and following the inspections. This test is also included in the Cost Impact estimate of this proposed AD.

These differences have been coordinated with TCCA.

Clarification of Inspection Type

The Canadian airworthiness directive refers to the required inspections as “visual inspections.” In this proposed AD, we refer to these inspections as “general visual inspections.” Note 1 of this proposed AD defines this type of inspection.

Interim Action

This proposed AD is considered to be interim action. The inspection reports that are required by this proposed AD will enable the manufacturer to obtain better insight into the nature, cause, and extent of the corrosion of the shafts of the MLG side-brace fittings, and eventually to develop final action to address the unsafe condition. Once final action has been identified, we may consider further rulemaking.

Cost Impact

We estimate that 462 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 5 work hours per airplane to accomplish the proposed inspections and functional test, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $150,150, or $325 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Bombardier, Inc. (Formerly Canadair): Docket 2003-NM-11-AD.

Applicability: Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, serial numbers 7003 through 7651 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fractures of the main landing gear (MLG) side-brace fitting shafts, and possible collapse of the MLG, accomplish the following:

Inspections, Corrective Actions, and Related Actions

(a) Within 20 months or 4,000 flight cycles after the effective date of this AD, whichever occurs first: Do a general visual inspection of the shafts of the side-brace fittings of the MLG for corrosion, and of the forward and aft bushings in the left-hand and right-hand MLG side-brace fittings for discrepancies (gouges, scores, corrosion, or other damage); and any applicable corrective and related actions. Do all of the actions per the Accomplishment Instructions of Bombardier Service Bulletin 601R-57-036, Revision ‘C’, including Appendix A, dated January 30, 2003. Do any applicable corrective and related actions prior to further flight. Where the service bulletin specifies to contact the manufacturer for certain replacement instructions: Before further flight, replace per a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent).

Note 1:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Reporting

(b) Submit a report of any corrosion of the shafts of the side-brace fittings of the MLG found during the inspections required by paragraph (a) of this AD to the Bombardier Technical Help Desk at fax number [phone]. Submit the report at the applicable time specified in paragraph (b)(1) or (b)(2) of this AD. Submission of the Field-Report Data Sheet in Appendix A of the service bulletin is an acceptable method for complying with this requirement. Include the inspection results (including the percentage of the corrosion), a digital photo of the shafts (if available), the location (zone) in which the corrosion is found, the serial number of the airplane, the name of the inspector, the service bulletin number, and the date of the inspection. Under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If the inspections are done after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspections were done prior to the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Actions Accomplished Per Previous Issue of Service Bulletin

(c) Actions accomplished before the effective date of this AD per Bombardier Service Bulletin 601R-57-036, Revision ‘A’, including Appendix A, dated May 17, 2002; or Revision ‘B’, including Appendix A, dated July 4, 2002; are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, New York ACO, is authorized to approve alternative methods of compliance for this AD.

Note 2:

The subject of this AD is addressed in Canadian airworthiness directive CF-2002-41, dated September 20, 2002.

Issued in Renton, Washington, on June 3, 2004.

Franklin Tiangsing,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.