E6-10090. Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. The existing AD currently requires repetitive detailed and eddy current inspections of the main fittings of the main landing gears (MLG) to detect discrepancies, and related investigative/corrective actions if necessary. The existing AD also requires servicing the shock strut of the MLGs; inspecting the shock strut of the MLGs for nitrogen pressure, visible chrome dimension, and oil leakage; and servicing any discrepant strut. This proposed AD would require installing a new, improved MLG main fitting, which would terminate the repetitive inspection and servicing requirements of the existing AD. This proposed AD results from stress analyses that showed certain main fittings of the MLGs are susceptible to premature cracking, starting in the radius of the upper lug. We are proposing this AD to detect and correct premature cracking of the main fittings of the MLGs, which could result in failure of the fittings and consequent collapse of the MLGs during landing.

DATES:

We must receive comments on this proposed AD by July 27, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to

http://dms.dot.gov and follow the instructions for sending your comments electronically.

• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Richard Beckwith, 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

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “Docket No. FAA-2006-25192; Directorate Identifier 2006-NM-004-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may 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 DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

On June 30, 2004, we issued AD 2004-14-16, amendment 39-13725 (69 FR 41421, July 9, 2004) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. That AD requires repetitive detailed and eddy current inspections of the main fittings of the main landing gears (MLG) to detect discrepancies, and related investigative/corrective actions if necessary. That AD also requires servicing the shock strut of the MLGs; inspecting the shock strut of the MLGs for nitrogen pressure, visible chrome dimension, and oil leakage; and servicing any discrepant strut. That AD resulted from stress analyses that showed certain main fittings of the MLGs are susceptible to premature cracking, starting in the radius of the upper lug. We issued that AD to detect and correct premature cracking of the main fittings of the MLGs, which could result in failure of the fittings and consequent collapse of the MLGs during landing.

Actions Since Existing AD Was Issued

Since we issued AD 2004-14-16, the manufacturer has designed a new MLG main fitting. Installing this new fitting terminates the inspection requirements currently mandated by AD 2004-14-16.

Other Relevant Rulemaking

On October 22, 2001, we issued AD 2001-22-09, amendment 39-12488 (66 FR 54658, October 30, 2001), for certain Bombardier Model CL-600-2B19 series airplanes. That AD requires repetitive eddy current inspections for cracking of the MLG main fittings, and replacement with a new or serviceable MLG, if necessary. That AD also requires servicing the MLG shock struts; inspecting the MLG shock struts for nitrogen pressure, visible chrome dimension, and oil leakage; and performing corrective actions, if necessary. That AD was prompted by reports of premature failure of the MLG main fitting. We issued that AD to prevent failure of the MLG main fitting, which could result in collapse of the MLG upon landing. AD 2001-22-09 inspects MLG main fittings that are similar to those addressed by this proposed AD. AD 2001-22-09 is relevant to this proposed AD because we are considering superseding AD 2001-22-09 with a new AD that would have the same terminating action as that in this proposed AD.

On September 27, 2004, we issued AD 2004-20-09, amendment 39-13814 (69 FR 59790, October 6, 2004), for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. That AD requires repetitive inspections for cracks, sealant damage, and corrosion of the main fittings of the MLG, and corrective actions if necessary. That AD was prompted by a report of a cracked main fitting of the MLG. We issued that AD to detect and correct fatigue cracking of the main fitting of the MLG and consequent failure of the main fitting, which could result in the collapse of the MLG. AD 2004-20-09 addresses the same unsafe condition on MLG main fittings that have different part numbers. AD 2004-20-09 is relevant to this proposed AD because we are considering superseding AD 2004-20-09 with a new AD that would have the same terminating action as that in this proposed AD.

Relevant Service Information

Bombardier has issued Service Bulletin 601R-32-093, Revision B, dated July 14, 2005. The service bulletin describes procedures for replacing the main fitting of the MLG with a new main fitting having a new part number (P/N).

Bombardier has also issued Alert Service Bulletin 601R-32-088, Revision A, dated June 16, 2005, including Appendices A, B, and C, dated February 20, 2003. The procedures in this service bulletin are essentially the same as those in Bombardier Service Bulletin 601R-32-088, including Appendices A, B, and C, dated February 20, 2003, which was referenced as the appropriate source of service information for doing the actions in AD 2004-14-16. Revision A makes changes that do not affect the technical content of the service bulletin.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, mandated the service information and issued Canadian airworthiness directive CF-2003-09R1, dated September 21, 2005, to ensure the continued airworthiness of these airplanes in Canada.

Bombardier Service Bulletin 601R-32-093 refers to Messier-Dowty Service Bulletin M-DT SB17002-32-25, Revision 1, dated October 17, 2003, as an additional source of service information for replacing the main fittings.

FAA's Determination and Requirements of the Proposed AD

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. We have examined TCCA's findings, evaluated all pertinent information, and determined that AD action is necessary for airplanes of this type design that are certificated for operation in the United States.

This proposed AD would supersede AD 2004-14-16 and retain the requirements of the existing AD. This proposed AD would also require replacing the main fitting of the MLG with a new main fitting having a new P/N. Doing this replacement would terminate the repetitive inspection and servicing requirements of AD 2004-14-16.

Differences Between the Proposed AD and the Canadian Airworthiness Directive

Although the Canadian airworthiness directive specifies to report certain information to the manufacturer, and although that action was included in AD 2004-14-16, this proposed AD would not continue to require those reports. We find that the reports are no longer necessary because the purpose of the reports was to help identify and develop a terminating action for the repetitive inspections. That terminating action has been developed and is the subject of this proposed AD.

Although the applicability of the Canadian airworthiness directive does not specify serial numbers (S/Ns) of the affected airplanes, we have included the affected S/Ns in this proposed AD for clarity.

Changes to Existing AD

This proposed AD would retain certain requirements of AD 2004-14-16. Since AD 2004-14-16 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2004-14-16	Corresponding requirement in this proposed AD
Paragraph (a)	Paragraph (f).
Paragraph (b)	Paragraph (g).
Paragraph (c)	Paragraph (h).
Paragraph (d)	Paragraph (i).
Paragraph (e)	Paragraph (j).

We have also revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved alternative method of compliance (AMOC) on any airplane to which the AMOC applies.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD. There are approximately 278 airplanes of U.S. registry that would be affected by this proposed AD. The average labor rate is $80 per work hour.

Estimated Costs

Action	Work hours	Parts	Cost per airplane	Fleet cost
Inspections (required by AD 2004-14-16)	4	None	$320, per inspection cycle	$88,960, per inspection cycle.
Replacement (new proposed action)	46	$105,732	$109,412	$30,416,436.

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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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 proposed AD and placed it in the AD docket. 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
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 Federal Aviation Administration (FAA) amends § 39.13 by removing amendment 39-13725 (69 FR 41421, July 9, 2004) and adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly Canadair): Docket No. FAA-2006-25192; Directorate Identifier 2006-NM-004-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 27, 2006.

Affected ADs

(b) This AD supersedes AD 2004-14-16.

Applicability

(c) This AD applies to Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, serial numbers 7003 and subsequent; certificated in any category; equipped with main landing gear (MLG) main fittings, part numbers (P/N) 601R85001-81 and 601R85001-82 (Messier Dowty Incorporated P/Ns 17064-105 and 17064-106).

Unsafe Condition

(d) This AD results from stress analyses that showed certain main fittings of the MLGs are susceptible to premature cracking, starting in the radius of the upper lug. We are issuing this AD to detect and correct premature cracking of the main fittings of the MLGs, which could result in failure of the fittings and consequent collapse of the MLGs during landing.

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.

Restatement of the Requirements of AD 2004-14-16

Detailed Inspection of Main Fittings of the MLGs

(f) Before the accumulation of 2,500 total flight cycles on the MLGs, or within 250 flight cycles after August 13, 2004 (the effective date of AD 2004-14-16), whichever occurs later: Do a detailed inspection on the main fittings of the MLGs to detect discrepancies (i.e., linear paint cracks or lack of paint (paint peeling), any other paint damage, adhesion, paint bulging, or corrosion), in accordance with Part A of the Accomplishment Instructions of Bombardier Alert Service Bulletin (ASB) A601R-32-088, dated February 20, 2003; or Bombardier ASB 601R-32-088, Revision A, dated June 16, 2005, including Appendices, A, B, and C, dated February 20, 2003. Repeat the inspection thereafter at intervals not to exceed 100 flight cycles until paragraph (k) of this AD is accomplished.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Related Investigative/Corrective Actions

(g) If any discrepancy is detected during any inspection required by paragraph (f) of this AD, before further flight: Do the related investigative/corrective actions in accordance with Part B or F of the Accomplishment Instructions of Bombardier ASB A601R-32-088, including Appendices A and C, dated February 20, 2003; or Bombardier ASB A601R-32-088, Revision A, dated June 16, 2005, including Appendices A, B, and C, dated February 20, 2003. If an eddy current inspection (a related investigative action specified in Part B) is used to confirm the detailed inspection findings, the next eddy current required by paragraph (h) of this AD must be conducted within 500 flight cycles after the eddy current inspection specified in this paragraph, and thereafter at intervals not to exceed 500 flight cycles until paragraph (k) of this AD is accomplished.

Eddy Current Inspection of Main Fittings of the MLGs

(h) At the time specified in paragraph (f) of this AD, do an eddy current inspection on the main fittings of the MLGs to detect cracks in accordance with Part B of the Accomplishment Instructions of Bombardier ASB A601R-32-088, including Appendix A, dated February 20, 2003; or Bombardier ASB A601R-32-088, Revision A, dated June 16, 2005, including Appendixes, A, B, and C, dated February 20, 2003. Repeat the eddy current inspection thereafter at intervals not to exceed 500 flight cycles, until paragraph (k) of this AD is accomplished. If any crack is found, before further flight, replace the affected main fittings of the MLGs with new or serviceable fittings in accordance with paragraph E.(5) of Part B of the Accomplishment Instructions of the service bulletin or in accordance with paragraph (k) of this AD. If any crack is found after the effective date of this AD, do the replacement in accordance with paragraph (k) of this AD.

Servicing of Shock Struts

(i) Before the accumulation of 2,500 total flight cycles on the MLGs, or within 500 flight cycles after August 13, 2004, whichever occurs later, service the shock strut of the MLGs in accordance with Part C or D, as applicable, of the Accomplishment Instructions of Bombardier ASB A601R-32-088, including Appendix B, dated February 20, 2003; or Bombardier ASB A601R-32-088, Revision A, dated June 16, 2005, including Appendices A, B, and C, dated February 20, 2003.

Shock Strut Inspection

(j) Within 500 flight cycles after completing the servicing required by paragraph (i) of this AD, inspect the shock strut of the MLGs for nitrogen pressure, visible chrome dimension, and oil leakage in accordance with Part E of the Accomplishment Instructions of Bombardier ASB A601R-32-088, including Appendix B, dated February 20, 2003; or Bombardier ASB A601R-32-088, Revision A, dated June 16, 2005, including Appendices A, B, and C, dated February 20, 2003. Repeat the inspection thereafter at intervals not to exceed 500 flight cycles, until paragraph (k) of this AD is accomplished. If the nitrogen pressure and visible chrome dimensions are found outside the limits (the service bulletin refers to the airplane maintenance manual as the source of defined limits) and/or oil leakage is found, before further flight, service the affected shock strut of the MLGs in accordance with Part C or D, as applicable, of the Accomplishment Instructions of the service bulletin.

New Requirements of This AD

Replacement

(k) Within 39 months after the effective date of this AD: Replace the main fittings of the MLGs, P/Ns 601R85001-81 and 601R85001-82 (Messier Dowty Incorporated P/Ns 17064-105 and 17064-106), with new main fittings, P/Ns 601R85001-83 and 601R85001-84 (Messier Dowty Incorporated P/Ns 17064-107 and 17064-108), in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 601R-32-093, Revision B, dated July 14, 2005. Doing this replacement terminates all requirements of paragraphs (f), (g), (h), (i), and (j) of this AD.

Note 2:

Bombardier Service Bulletin 601R-32-093, Revision B, refers to Messier Dowty M-DT Service Bulletin SB17002-32-25, Revision 1, dated October 17, 2003, as an additional source of service information for replacing the main fittings.

Parts Installation

(l) As of the effective date of this AD, no person may install a main fitting of the MLG, P/Ns 601R85001-81 and 601R85001-82 (Messier Dowty Incorporated P/Ns 17064-105 and 17064-106), on any airplane.

No Reporting Required

(m) Although the Accomplishment Instructions of Bombardier ASB A601R-32-088, dated February 20, 2003; and ASB 601R-32-088, Revision A, dated June 16, 2005; specify to report certain information to the manufacturer, this AD does not include that action.

Actions Accomplished in Accordance With Previous Revisions of Service Bulletin

(n) Actions accomplished before the effective date of this AD in accordance with the service bulletins listed in Table 1 of this AD are acceptable for compliance with the actions in paragraph (k) of this AD.

Table 1.—Previous Revisions of Service Bulletin

Bombardier Service Bulletin	Revision level	Date
601R-32-093	Original	October 17, 2003.
601R-32-093	A	September 21, 2004.

Alternative Methods of Compliance (AMOCs)

(o)(1) The Manager, New York Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(p) Canadian airworthiness directive CF-2003-09R1, dated September 21, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on June 5, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.