01-7174. Airworthiness Directives; Bombardier Model CL-600-2B19 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 series airplanes, that would have required repetitive eddy current inspections for cracking of the main landing gear (MLG) main fittings, and replacement with a new or serviceable MLG, if necessary. This new action revises the proposed rule by continuing to require the repetitive eddy current inspections of the MLG; and adds requirements to service the MLG shock struts, inspect the MLG shock struts for nitrogen pressure, visible chrome dimension, and oil leakage, and perform corrective actions, if necessary. The actions specified by this new proposed AD are intended to prevent failure of the MLG main fitting, which could result in collapse of the MLG upon landing. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by April 17, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-68-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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. 2000-NM-68-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 for Windows 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, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:

Serge Napoleon, Aerospace Engineer, ANE-171, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; 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 2000-NM-68-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. 2000-NM-68-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Bombardier Model CL-600-B219 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on August 23, 2000 (65 FR 51259). That NPRM would have required repetitive eddy current inspections for cracking of the main landing gear (MLG) main fittings, and corrective action, if necessary. Such cracking of the MLG, if not corrected, could result in collapse of the MLG upon landing.

Since the Issuance of Previous Proposal

Further investigation into the premature failure of the MLG main fitting has revealed that, under certain conditions, an improperly serviced shock strut could lead to the premature failure of the MLG main fitting.

Issuance of New Service Information

Since the issuance of the previous proposal, Bombardier issued Alert Service Bulletin (ASB) A601R-32-079, Revision D, dated December 1, 2000, that describes procedures for repetitive eddy current inspections to detect cracking of the MLG, and replacement of any cracked fitting with a new or serviceable fitting. Revision D of the ASB also describes procedures for servicing the MLG shock struts, and repetitive inspections to determine the nitrogen pressure, visible chrome dimension, and any oil leakage. The ASB also describes corrective procedures for servicing the MLG, if necessary. The Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, issued Canadian airworthiness directive CF-1999-32R1, dated January 22, 2001, in order to assure the continued airworthiness of these airplanes in Canada.

Differences Between Service Information and this Proposed Rule

Operators should note that, although Revision D of Bombardier ASB A601R-32-079 also includes procedures for performing a visual inspection to detect cracking of the MLG, this proposed rule would not require that inspection. The FAA finds that a visual inspection in this area of the landing gear would not be reliable or effective in determining the existence of a crack at that location. This finding also is consistent with the findings of the TCCA.

Comments Received to Proposed Rule

Due consideration has been given to the comments received in response to the proposed rule.

One commenter, the manufacturer, requests that the FAA revise the NPRM to add new inspections of the MLG shock struts in accordance with Revision D of ASB A601R-32-079. The manufacturer states that results of an investigation indicate that, under certain conditions, an improperly serviced shock strut may be the probable cause of premature failure of the MLG main fitting. (The cause of cracking of the MLG fittings that were specified in the preamble of the NPRM was not known at that time.) Therefore, the manufacturer requests that the inspections of the shock struts, in accordance with the new service bulletin revision, be required.

The FAA agrees with the commenter for the reasons specified. We have added new paragraphs, (c) and (d), to this supplemental NPRM, which would require the previously described inspections of the fitting, and corrective actions, if necessary, per Revision D of the ASB.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Conclusion

Since this change expands the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Cost Impact

There are approximately 339 Bombardier Model CL-600-2B19 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 236 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 3 work hours per airplane to accomplish an eddy current inspection, and the servicing actions, and inspections specified in paragraphs (a), (b), and (c) of this AD. We estimate that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $42,480, or $180 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 2000-NM-68-AD.

Applicability: Model CL-600-2B19 series airplanes, certificated in any category, serial numbers 7003 and subsequent.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (g) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the main fitting of the main landing gear (MLG), which could result in collapse of the MLG upon landing, accomplish the following:

Inspection and Replacement

(a) Prior to the accumulation of 1,500 total flight cycles, or within 150 flight cycles after the effective date of this AD, whichever occurs later: Perform an eddy current inspection to detect cracking of the MLG main fittings, in accordance with Part B of the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 2000. If any cracking is found, prior to further flight, replace the cracked fitting with a new or serviceable fitting in accordance with the alert service bulletin. Repeat the inspection thereafter at intervals not to exceed 500 flight cycles.

Servicing the Shock Struts

(b) Prior to the accumulation of 1,500 total flight cycles since the date of manufacture, or within 500 flight cycles after the effective date of this AD, whichever occurs later: Perform a servicing (Oil and Nitrogen) of the MLG shock struts (left and right main landing shock struts), in accordance with Part C (for airplanes on the ground) or Part D (for airplanes on jacks) of the Accomplishment Instructions of the Bombardier Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 2000.

Other Inspections

(c) Within 500 flight cycles after completing the actions required by paragraph (b) of this AD: Perform an inspection of the MLG left and right shock struts for nitrogen pressure, visible chrome dimension, and oil leakage, in accordance with Part E of the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 2000. Thereafter, repeat the inspection at intervals not to exceed 500 flight cycles.

Corrective Actions for Certain Inspections

(d) If the chrome extension dimension of the shock strut pressure reading is outside the limits specified in the Airplane Maintenance Manual, Task 32-11-05-220-801, or any oil leakage is found: Prior to further flight, service the MLG shock strut in accordance with Part C (for airplanes on the ground) or Part D (for airplanes on jacks) of the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 2000.

Extension of the Repetitive Interval

(e) After the effective date of this AD: After a total of five consecutive inspections of the MLG shock struts that verify that the shock struts are serviced properly, and a total of five consecutive eddy current inspections of the MLG main fitting has been accomplished that verify there is no cracking of the main fitting, in accordance with Bombardier Alert Service Bulletin A601R-32-079, Revision D, dated December 1, 2000, the repetitive interval for the eddy current inspections required by paragraph (a) of this AD may be extended from every 500 flight cycles to every 1,000 flight cycles.

Reporting Requirement

(f) Within 30 days after each inspection and servicing required by paragraphs (a), (b), and (c) of this AD, report all findings, positive or negative, to: Bombardier Aerospace, Regional Aircraft, CRJ Action Desk, fax number 514-855-8501. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance

(g) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

Special Flight Permits

(h) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Note 3:

The subject of this AD is addressed in Canadian airworthiness directive CF-1999-32R1, dated January 22, 2001.

Issued in Renton, Washington, on March 15, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.