AD 2004-20-09

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This AD requires repetitive inspections for cracks, sealant damage, and corrosion of the main fittings of the main landing gear (MLG), and corrective actions if necessary. This AD is prompted by a report of a cracked main fitting of the MLG. We are issuing this 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.

Final rule; request for comments.

2004-20-09 Bombardier, Inc. (Formerly Canadair): Amendment 39-13814. Docket No. FAA-2004-19229; Directorate Identifier 2004-NM-195-AD.

Effective Date

(a) This AD becomes effective October 21, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, serial numbers 7003 through 7067 inclusive and 7069 through 8999 inclusive, certificated in any category; equipped with main landing gear (MLG) main fittings, part number (P/N) 601R85001-3 or -4 (Messier Dowty P/N 17064-101, -102, - 103, or -104).

Unsafe Condition

(d) This AD was prompted by a report of a cracked main fitting of the MLG. The FAA is issuing this 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.

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.

Service Bulletin

(f) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-32-099, including Appendices A, B, and D, and excluding Appendix C, dated September 15, 2004.

Initial Inspections

(g) Do the actions specified in Table 1 of this AD.

Table 1.--Initial Inspections

Do-
At the latest of-

(i) Before the accumulation of 8,000 total flight cycles since the main fitting of the MLG was new.

(ii) Within 8,000 flight cycles since the last overhaul of the MLG.

(1) A detailed inspection for cracks of the inboard and outboard sides of the main fitting of the MLG between the pintle pin trunnion and the radius of the shock strut lug, in accordance with Part A of the service bulletin.
(iii) Within 50 flight cycles after the effective date of this AD.

(i) Before the accumulation of 8,000 total flight cycles since the main fitting of the MLG was new.

(ii) Within 8,000 flight cycles since the last overhaul of the MLG.

(2) A detailed inspection for sealant damage or corrosion around the forward bushing of the left and right main fittings of the MLG, in accordance with Part B of the service bulletin.
(iii) Within 500 flight cycles after the effective date of this AD.

(i) Before the accumulation of 8,000 total flight cycles since the main fitting of the MLG was new.

(ii) Within 8,000 flight cycles since the last overhaul of the MLG.

(3) An ultrasonic inspection for cracks of the left and right main fittings of the MLG, in accordance with Part C of the service bulletin.
(iii) Within 500 flight cycles after the effective date of this AD.

Note 1: For the purposes of this AD, a detailed inspection is "an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required."

Repetitive Inspections

(h) Repeat the inspections required by paragraph (g) of this AD at the time specified in Table 2 of this AD.

Table 2.--Repetitive Inspection Interval

For the inspection required by-
Repeat at intervals not to exceed-
Until the action required by-

(1) Paragraph (g)(1) of this AD
5 days
Paragraph (g)(3) of the AD is done, un-
less required by paragraph (j) of this
AD.
(2) Paragraph (g)(2) of this AD
500 flight cycles
Paragraph (j)(2) of this AD is done.

(3) Paragraph (g)(3) of this AD
5,000 flight cycles, except as required by paragraph (j)(2) of this AD.
(None).

Corrective Actions

(i) If there is an indication of a crack during any inspection required by paragraph (g)(1), (h)(1), or (j)(1) of this AD, before further flight, do the actions specified in paragraphs (i)(1) or (i)(2) of this AD in accordance with Part A of the service bulletin.

(1) Replace the cracked main fitting of the MLG with a new or serviceable main fitting.

(2) Do an eddy current inspection to verify whether there is a crack. If there is a crack, replace the cracked main fitting of the MLG with a new or serviceable main fitting.

(j) If any sealant damage or corrosion is found during any inspection required by either paragraph (g)(2) or (h)(2) of this AD, do the actions specified in Table 3 of this AD in accordance with Part B of the service bulletin.

Table 3.--Corrective Actions for Sealant Damage or Corrosion

Do the inspection specified in-
Within-
Repeat at intervals not to exceed-
Until the action specified in-

(1) Paragraph (g)(1) of this AD
5 days after doing the inspection required by paragraph (g)(2) or (h)(2) of this AD, as aplicable.
5 days
Paragraph (j)(2) of this AD is
done.

(2) Paragraph (g)(3) of this AD
500 flight cycles after doing the inspection required by paragraph (g)(2) or (h)(2) of this AD, as applicable.
500 flight cycles
(None).

(k) If there is an indication of a crack during any inspection required by paragraph (g)(3), (h)(3), or (j)(2) of this AD, before further flight, replace the cracked main fitting of the MLG with a new or serviceable main fitting in accordance with Part C of the service bulletin.

No Reporting or Returning of Parts

(l) Although the service bulletin referenced in this AD specifies to submit certain information to the airplane manufacturer and to return cracked main fittings to the supplier, this AD does not include those requirements.

Alternative Methods of Compliance (AMOCs)

(m) 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.

Related Information

(n) Canadian airworthiness directive CF-2004-18, dated September 16, 2004, also addresses the subject of this AD.

Material Incorporated by Reference

(o) You must use Bombardier Alert Service Bulletin A601R-32-099, including Appendices A, B, and D, and excluding Appendix C, dated September 15, 2004, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. For copies of the service information, contact Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. You can review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW, room PL-401, Nassif Building, Washington, DC; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to http://www.archives.gov/ federal_register/code_of_ federal_regulations/ibr_locations.html.

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 it has received a report of a cracked main fitting of the main landing gear (MLG) at the section between the forward face of the main fitting on the trunnion side and the area just above the upper attach lug radius of the shock strut. Laboratory examination has found that the fatigue crack was initiated from a corrosion pit located on the chamfer of the inner bore of the pintle pin socket of the main fitting of the MLG. This condition, if not detected and corrected in a timely manner, could cause failure of the main fitting of the MLG, which could result in the collapse of the MLG.

Relevant Service Information

Bombardier has issued Alert Service Bulletin A601R-32-099, including Appendices A through D, dated September 15, 2004. The service bulletin describes the following procedures:

Repetitive detailed inspections for cracks of the inboard and outboard sides of the main fitting of the MLG between the pintle pin trunnion and the radius of the shock strut lug;

Repetitive detailed inspections for sealant damage or corrosion around the forward bushing of the left and right main fittings of the MLG;

Repetitive ultrasonic inspections for cracks of the left and right main fittings of MLG; and

Corrective actions if necessary. The corrective actions include replacing any cracked main fitting of the MLG with a new or serviceable main fitting; doing an eddy current inspection to verify that there is a crack on the fitting if necessary; and repeating certain inspections described previously at reduced intervals; as applicable.

TCCA mandated the service bulletin and issued Canadian airworthiness directive CF-2004-18, dated September 16, 2004, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of This 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, TCAA has kept the FAA informed of the situation described above. We have examined TCCA's findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.

Therefore, we are issuing this 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. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and Referenced Service Bulletin/Canadian Airworthiness Directive."

Differences Between the AD and Referenced Service Bulletin/Canadian Airworthiness Directive

Operators should note that, although the Accomplishment Instructions of the referenced service bulletin describe procedures for reporting crack indications, returning cracked parts to Messier Dowty, and submitting a comment sheet related to service bulletin quality and a sheet recording compliance with the service bulletin, this AD, like Canadian airworthiness directive CF-2004-18, will not require those actions. We do not need this information from operators.

In addition, if there is evidence of sealant damage or corrosion, the referenced service bulletin describes procedures for accomplishing only the ultrasonic inspection at intervals not to exceed 500 flight cycles. This AD, as well as the Canadian airworthiness directive, requires repeating the detailed inspection of the main fitting lateral surface within 5 days following the visual inspection of the sealant, and every 5 days thereafter, in addition to the ultrasonic inspections of the main fittings within 500 flight cycles.

Canadian airworthiness directive CF-2004-18 specifies that the required actions must be done in accordance with Bombardier Alert Service Bulletin A601R-32-099, dated September 15, 2004, or "later revisions approved by the Chief, Continuing Airworthiness, Aircraft Certification, Transport Canada." We cannot use the phrase, "or later FAA-approved revisions," in an AD when referring to the service document because doing so violates Office of the Federal Register (OFR) regulations for approval of materials "incorporated by reference" in rules. In general terms, we are required by these OFR regulations to either publish the service document contents as part of the actual AD language; or submit the service document to the OFR for approval as "referenced" material, in which case we may only refer to such material in the text of an AD. The AD may refer to the service document only if the OFR approved it for "incorporation by reference." To allow operators to use later revisions of the referenced document (issued after publication of the AD), either we must revise the AD to reference specific later revisions, or operators must request approval to use later revisions as an alternative method of compliance with this AD under the provisions of paragraph (m) of this AD.

Interim Action

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

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2004-19229; Directorate Identifier 2004-NM-195-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 AD. Using the search function of our docket 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 thecomment on behalf of an association, business, labor union, etc.). You can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications with you. You can get more information about plain language at http://www/faa.gov/language and http://www.plainlanguage.gov.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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 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 AD. 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, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 FAA amends 39.13 by adding the following new airworthiness directive (AD):