E7-18539. 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 adopt a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This proposed AD would require repetitive detailed inspections for cracking of the left side and right side frame and reinforcement angles at fuselage station (FS) 640 between stringer 9 and stringer 12, and corrective actions if necessary. This proposed AD results from reports that cracks have been discovered on the frame and reinforcement angles at FS 640. We are proposing this AD to detect and correct cracking of the frame, which could lead to failure of the fuselage structure and possible loss of the airplane.

DATES:

We must receive comments on this proposed AD by October 22, 2007.

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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., 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:

Pong K. Lee, 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 “FAA-2007-29257; Directorate Identifier 2007-NM-144-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 Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located on the ground level of the West 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

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. TCCA advises that cracks have been discovered on the frame and reinforcement angles at fuselage station (FS) 640 on a number of CRJ (Canadair Regional Jet) airplanes. This condition, if not corrected, could result in failure of the fuselage structure and possible loss of the airplane.

Relevant Service Information

Bombardier has issued Alert Service Bulletin 601R-53-061, Revision E, dated December 7, 2006. The alert service bulletin describes procedures for doing repetitive detailed visual inspections for cracking of the frame at fuselage station (FS) 640 between stringer 9 and stringer 12 (Part A of the Accomplishment Instructions) and, if necessary, corrective actions as follows:

• Repair as described in Part A of the Accomplishment Instructions;
• Install a modification, including related investigative and corrective actions; or
• Contact Bombardier for repair instructions.

The related investigative and corrective actions of the modification (Part C of the Accomplishment Instructions) include cutting out a section of the flange frame at FS640 then doing a liquid penetrant or eddy current inspection for cracking of the skin doubler, and contacting Bombardier for repair instructions. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. TCCA mandated the service information and issued Canadian airworthiness directive CF-2003-12, dated May 7, 2003, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

These airplanes are manufactured in Canada and are 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 we need to issue an AD for airplanes of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and Bombardier Alert Service Bulletin/Canadian Airworthiness Directive.”

Differences Between the Proposed AD and Bombardier Alert Service Bulletin/Canadian Airworthiness Directive

The Canadian airworthiness directive specifies that Bombardier Alert Service Bulletin 601R-53-061, Revision B, dated February 20, 2003, or later revisions, must be used to do all described inspections and actions. However, we have determined that Revision E, dated December 7, 2006, of the alert service bulletin no longer contains certain actions described by Revision B. Therefore, this proposed AD would require doing all actions in accordance with Alert Service Bulletin 601R-53-061, Revision E, dated December 7, 2006. This difference has been coordinated with TCCA.

In this proposed AD, the “detailed visual inspection” specified in the Bombardier alert service bulletin and Canadian airworthiness directive is referred to as a “detailed inspection.” We have included the definition for a detailed inspection in a note in the proposed AD.

The Bombardier alert service bulletin and Canadian airworthiness directive specify to contact Bombardier for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions using a method approved by the FAA or TCCA (or its delegated agent). In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair approved by the FAA or TCCA (or its delegated agent) would be acceptable for compliance with this proposed AD.

Although the Accomplishment Instructions of the alert service bulletin describe procedures for submitting certain information to the manufacturer, this proposed AD would not require that action.

Interim Action

We consider this proposed AD interim action. If final action is later identified, we might consider further rulemaking then.

Costs of Compliance

This proposed AD would affect about 739 airplanes of U.S. registry. The proposed inspection would take about 2 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $118,240, or $160 per airplane, per inspection cycle.

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 adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly Canadair): Docket No. FAA-2007-29257; Directorate Identifier 2007-NM-144-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by November 5, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, certificated in any category; as identified in Bombardier Alert Service Bulletin 601R-53-061, Revision E, dated December 7, 2006.

Unsafe Condition

(d) This AD results from reports that cracks have been discovered on the frame and reinforcement angles at fuselage station (FS) 640. Failure of this frame could degrade the structural integrity of the airplane. We are issuing this AD to detect and correct cracking of the frame, which could lead to failure of the fuselage structure and possible loss of the airplane.

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 Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Bombardier Alert Service Bulletin 601R-53-061, Revision E, dated December 7, 2006.

Detailed Inspection

(g) Before the accumulation of 8,600 total flight cycles or within 1,100 flight cycles after the effective date of this AD, whichever occurs later: Perform a detailed inspection to detect cracking of the left side and right side frames and reinforcement angles at FS640 between stringer 9 and stringer 12, in accordance with Part A of the Accomplishment Instructions of the service bulletin.

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 mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Repetitive Inspection and Corrective Action

(h) If no crack is found during the inspection required by paragraph (g) of this AD: Repeat the detailed inspection thereafter at intervals not to exceed 1,100 flight cycles, until the frame modification described in paragraph (i)(2) of this AD has been done.

(i) If any crack is found during the inspection required by paragraph (g) of this AD: Before further flight, repair the crack in accordance with paragraph (i)(1), (i)(2), or (i)(3) of this AD, as applicable.

(1) For any crack found in the frame at the stringer 9 cut-out only, repair in accordance with Part A of the Accomplishment Instructions of the service bulletin.

(2) For any crack found in the frame reinforcement doubler only: Do the frame modification (including related investigative and corrective actions) described in Part C of the Accomplishment Instructions of the service bulletin, except where the alert service bulletin specifies to contact the manufacturer for repair instructions, repair the crack using a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent); then do the detailed inspection required by paragraph (j) of this AD.

(3) For any crack found in areas of the inspection zone described in paragraph (g) of this AD other than those described in paragraphs (i)(1) and (i)(2) of this AD: Repair the crack using a method approved by either the Manager, New York ACO, FAA; or TCCA (or its delegated agent).

Repetitive Inspection After Frame Modification

(j) Within 12,000 flight cycles after doing the modification described in paragraph (i)(2) of this AD, do the detailed inspection required by paragraph (g) of this AD. Repeat the detailed inspection thereafter at intervals not to exceed 1,100 flight cycles.

No Reporting Requirement

(k) Although the alert service bulletin referred to in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(l)(1) The Manager, New York 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) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Related Information

(m) Canadian airworthiness directive CF-2003-12, dated May 7, 2003, also addresses the subject of this AD.

Issued in Renton, Washington, on September 12, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.