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 all Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This proposal would require repetitive inspections of the check valves and air supply ducts of the rear bulkhead for damage, and related corrective actions. This proposal also would require eventual rework or replacement of the air supply ducts, which would terminate the repetitive inspections for the air supply ducts only. This action is necessary to prevent disconnection of an air supply duct, which, if combined with failure of a bulkhead check valve, could result in rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by July 2, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-158-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-158-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, New York Aircraft Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New York; or at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Dan Parillo, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, suite 410, New York 11590; telephone (516) 228-7305; fax (516) 794-5531.

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-158-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-158-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 all Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. TCCA advises that the flanges on the air supply ducts of the rear bulkhead were bonded to the duct using a manufacturing procedure that did not meet design specifications. Investigation revealed that such bonding could lose 80 percent of its shear strength at elevated temperatures. If the bonding loses shear strength, it could result in premature cracking and consequent failure (detachment of the flappers) of the bulkhead check valve. Disconnection of an air supply duct, if combined with failure of a bulkhead check valve, could result in rapid depressurization of the airplane.

Explanation of Relevant Service Information

Bombardier has issued Alert Service Bulletin A601R-21-053, Revision “A”, dated January 28, 2003, which describes procedures for repetitive inspections of the air supply ducts of the rear bulkhead for damage. Bombardier has also issued Alert Service Bulletin A601R-21-054, dated November 8, 2001, which describes procedures for repetitive inspections of the check valves of the rear bulkhead for damage. Both service bulletins describe procedures for related corrective actions if any damage is found. Service Bulletin A601R-21-054 recommends that Service Bulletin A601R-21-053, Revision “A”, be done at the same time.

Service Bulletin A601R-21-053, Revision “A”, describes procedures for the following: A visual inspection of the left- and right-hand air supply ducts for damage (tearing, delamination, or cracking). If any damage is found, the corrective action involves replacement of the affected duct with a new duct before further flight, which eliminates the need for the repetitive inspections for that duct only. If no damage is found, the inspection is repeated. The service bulletin also describes procedures for eventual rework or replacement of the air supply ducts, which eliminates the need for the repetitive inspections of the air supply ducts.

Service Bulletin A601R-21-054 describes procedures for the following: A visual inspection of the bulkhead check valves (including the guide clamps) for damage (cracking or breakage), and a leak test of the air conditioning system. If any damage is found, the corrective action involves replacement of the affected bulkhead check valve with a new valve before further flight. If no damage is found, the inspection is repeated.

Accomplishment of the actions specified in the service information is intended to adequately address the identified unsafe condition. TCCA classified this service information as mandatory and issued Canadian airworthiness directive CF-2003-05, dated February 4, 2003, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

This airplane model is manufactured in Canada and is 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 information described previously, except as discussed below.

Differences Among Canadian Airworthiness Directive, Service Information, and This Proposed AD

The applicability in the Canadian airworthiness directive specifies Bombardier Model CL-600-2B19 airplanes, serial numbers 7003 through 7477; however, the proposed AD would be applicable to all Bombardier Model CL-600-2B19 airplanes. TCCA has informed us that the Canadian airworthiness directive is in error, and should have specified all Bombardier Model CL-600-2B19 airplanes.

The Canadian airworthiness directive requires amending the Transport Canada approved maintenance schedule within 30 days after the effective date of the Canadian airworthiness directive, by incorporating Inspection Task No. 21-51-21-07, and incorporating the task interval for the bulkhead check valves, as specified in Part 1, Section 2, of Revision 7 of the Maintenance Review Board Report, dated April 11, 2001. However, this proposed AD does not contain such a requirement, but would mandate the equivalent maintenance tasks specified in Service Bulletin A601R-21-054, in lieu of amending the maintenance schedule. We have determined that these tasks address the unsafe condition in the same manner as would amending the maintenance schedule.

The Canadian airworthiness directive does not specifically cite a repetitive inspection interval for the check valves; Inspection Task No. 21-51-21-07, cited in the Canadian airworthiness directive, does require repetitive inspections. This proposed AD would require repeating the inspections of the check valves at intervals not to exceed 4,000 flight hours, which is in line with the Canadian requirements. The inspections will continue until a terminating action is developed, approved, and available.

The Canadian airworthiness directive and Service Bulletin A601R-21-054 recommend sending all damaged check valves to the manufacturer for analysis; however, this AD does not include that requirement.

The service bulletins referenced in this proposed AD specify to submit certain information to the manufacturer, but this proposed AD does not include such a requirement.

Clarification of Type of Inspection

The Canadian airworthiness directive and the referenced service bulletins specify that operators do a visual inspection of the check valves and air supply ducts of the rear bulkhead. We have determined that the inspection procedures should be described as a “detailed inspection.” Note 1 has been included in this proposed AD to define this type of inspection.

Interim Action

This proposed AD is considered to be interim action. Analysis of the check valves is being done by the manufacturer to obtain better insight into the nature, cause, and extent of the damage, 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 280 airplanes of U.S. registry would be affected by this proposed AD.

It would take about 2 work hours per airplane to accomplish the proposed inspection of the check valves, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $36,400, or $130 per airplane, per inspection cycle.

It would take about 4 work hours per airplane to accomplish the proposed inspection of the air supply duct, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $72,800, or $260 per airplane, per inspection cycle.

It would take about 4 work hours per airplane to accomplish the proposed replacement of the check valves, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the cost impact of the proposed replacement on U.S. operators is estimated to be $72,800, or $260 per airplane.

It would take about 3 work hours per airplane to accomplish the proposed rework of the air supply ducts, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the cost impact of the proposed rework on U.S. operators is estimated to be $54,600, or $195 per airplane.

It would take about 2 work hours per airplane to accomplish the proposed replacement of the air supply ducts, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the cost impact of the proposed replacement on U.S. operators is estimated to be $36,400, or $130 per airplane.

The cost impact figures discussed above are 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.