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Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

Published Document

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Start Preamble

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 series airplanes. This proposal would require a one-time inspection of the aft edge of the left and right main windshields to determine whether a certain placard is installed, and corrective actions if necessary. This action is necessary to prevent failure of the main windshields due to stress-related cracking, which could cause cabin depressurization and emergency descent, and adversely affect continued safe flight of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by June 19, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-322-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 (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. 2001-NM-322-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, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Serge Napoleon, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 10 Fifth Street, Start Printed Page 35462Third Floor, Valley Stream, New York 11581; telephone (516) 256-7512; fax (516) 568-2716.

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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 2001-NM-322-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. 2001-NM-322-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 series airplanes. TCCA advises that a significant number of cracking incidents have occurred in the inner and middle panes of the main windshields during taxi, takeoff, climb, cruise, and descent of the airplane. In addition, frequent cracking incidents during flight have resulted in emergency descent, which poses an increased risk to passengers and crew members. Findings indicate that most of the windshield failures are due to excessive stress at the lower forward corner of the windshield. Failure of the main windshields due to stress-related cracking, if not corrected, could cause cabin depressurization and emergency descent, and adversely affect continued safe flight of the airplane.

Background Information

Until a new design for the main windshield can be developed by the manufacturer and approved by the FAA, operators have requested procedures for modifying the existing windshields to address the identified unsafe condition and to improve service performance. In response, the manufacturer has conducted tests on windshield units similar to those used on in-service airplanes, and on windshield units fitted with reduced diameter fasteners (hi-lok pins with a reduced diameter shank). Findings indicate that the test units with reduced diameter fasteners did not fracture, unlike the windshield units fitted with the original diameter fasteners. Results of analysis and testing indicate that installation of reduced diameter fasteners in the lower forward corner of the windshield can reduce the stress in that area and increase the service life of the windshield. Findings also indicate that windshields with low flight cycles have a greater risk of windshield failure. As a result, the manufacturer recommends the “expeditious accomplishment” of applicable corrective actions for airplanes subject to this AD and equipped with certain windshield units that have accumulated fewer than 2,500 total flight cycles. This recommendation is based on the manufacturer's statistical analysis of the failure rate of those windshields, and also on the tests conducted on the windshields.

Explanation of Relevant Service Information

Bombardier has issued Service Bulletin 601R-56-004, dated August 16, 2001, which describes procedures for an inspection of the left and right main windshields to determine the part number of the placard installed on the aft edge of the windshields. If a placard having the correct part number is found, no further action is specified. If a placard having the incorrect part number is found, the service bulletin describes procedures for modifying the main windshields. The Bombardier service bulletin references PPG Industries, Inc., Service Bulletin CSB-NP-139321-002, Revision C, dated July 31, 2001, as a secondary source of service information for modifying the main windshields by replacing nine of the hi-lok pins installed in the lower forward corner of the windshields with hi-lok pins having a reduced diameter shank, installing a placard having the correct part number on the inner retainer near the part identification placard located along the aft edge of the window, and replacing any torn or deformed gasket.

TCCA classified the Bombardier service bulletin as mandatory and issued Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001, in order to assure the continued airworthiness of these airplanes in Canada.

FAA's Conclusion

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 the FAA informed of the situation described above. The FAA has 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 Rule

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

Difference Between Proposed Rule and Service Bulletin/Canadian Airworthiness Directive

Operators should note that the Canadian airworthiness directive and Bombardier Service Bulletin specify a compliance time of 12 months for the one-time inspection, and modification if necessary. However, this proposed AD would require a compliance time of 6 months after the effective date of this AD to accomplish the one-time general visual inspection, and any necessary Start Printed Page 35463modification. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the inspection, and modification if necessary. In light of these factors, the FAA finds a compliance time of 6 months after the effective date of this AD to be warranted, in that it represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Interim Action

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

Cost Impact

There are approximately 339 Model CL-600-2B19 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 214 airplanes of U.S. registry would be affected by this proposed AD.

The FAA estimates that it would take approximately 1 work hour per airplane to accomplish the inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed inspection is estimated to be $12,840, or $60 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 proposed 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.

Should an operator be required to accomplish the corrective actions, it would take approximately 1 work hour per airplane to accomplish at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to the operator. Based on these figures, the cost impact of the corrective actions is estimated to be $60 per airplane.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Bombardier, Inc. (Formerly Canadair): Docket 2001-NM-322-AD.

Applicability: Model CL-600-2B19 series airplanes; certificated in any category; serial numbers 7003 and subsequent; equipped with main windshield units, part numbers 601R33033-1, -2, -5, -6, -9, or -10.

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 (b) 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 windshields due to stress-related cracking, which could cause cabin depressurization and emergency descent, and adversely affect continued safe flight of the airplane; accomplish the following:

Inspection and Corrective Action

(a) For airplanes equipped with windshield units that have accumulated fewer than 2,500 total flight cycles as of the effective date of this AD: Within 6 months after the effective date of this AD, accomplish a one-time general visual inspection of the aft edges of the left and right main windshields to determine whether a placard having part number (P/N) CSB-NP-139321-002-1 is installed, per the Accomplishment Instructions of Bombardier Service Bulletin 601R-56-004, dated August 16, 2001.

(1) If a placard having P/N CSB-NP-139321-002-1 is installed, no further action is required by this AD.

(2) If a placard having a part number other than CSB-NP-139321-002-1 is installed, before further flight, accomplish the corrective actions (including modifying the main windshields by replacing nine of the hi-lok pins installed in the lower forward corner of the windshields with hi-lok pins having a reduced diameter shank, installing a placard having the correct part number on the inner retainer near the part identification placard located along the aft edge of the window, and replacing any torn or deformed gasket), per the Accomplishment Instructions of the service bulletin.

Note 2:

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.”

Note 3:

Bombardier Service Bulletin 601R-56-004, dated August 16, 2001, references PPG Industries, Inc., Service Bulletin CSB-NP-139321-002, Revision C, dated July 31, 2001, as an additional source of service information for accomplishment of the modification of the left and right main windshields.

Alternative Methods of Compliance

(b) 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.

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Note 4:

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 Permit

(c) Special flight permits may be issued in accordance with sections 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 5:

The subject of this AD is addressed in Canadian airworthiness directive CF-2001-35R1, dated September 27, 2001.

Start Signature

Issued in Renton, Washington, on May 13, 2002.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 02-12518 Filed 5-17-02; 8:45 am]

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