E6-1685. Airworthiness Directives; Aerospatiale Model ATR42 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 all Aerospatiale Model ATR42 airplanes. This proposed AD would require one-time inspections to detect discrepancies (e.g., cracking, loose/sheared fasteners, distortion) of the upper skin and rib feet of the outer wing boxes, and repair if necessary. This proposed AD results from a report of cracking on the upper skin and ribs of the outer wing box on an in-service airplane. We are proposing this AD to detect and correct these discrepancies, which could result in reduced structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by March 10, 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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 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-2006-23816; Directorate Identifier 2005-NM-247-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

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on all Aerospatiale Model ATR42 airplanes. The DGAC advises that cracking has been found on the upper skin and ribs of the outer wing box on an in-service airplane. This condition, if not corrected, could result in reduced structural integrity of the airplane.

Relevant Service Information

Aerospatiale has issued Avions de Transport Regional Service Bulletin ATR42-57-0064, dated December 16, 2004. The service bulletin describes procedures for doing an external detailed visual inspection for discrepancies of the upper skin panels of the outer wing box on the left and right wing, from rib 24 to rib 29. Discrepancies include cracking of the skin, cracked sealant, loose/sheared fasteners, and distortion. The service bulletin also describes procedures for doing an internal inspection following the external inspection. The internal inspection is to look for discrepancies of the rib feet from rib 24 to rib 29 and is conducted using one of two inspection methods: A borescopic inspection through access doors, or a detailed visual inspection after removing the leading edge of the wing. The service bulletin also describes procedures for sending inspection results to the manufacturer, and repairing any discrepancies using an “approved solution.” Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The DGAC mandated the service information and issued French airworthiness directive F-2004-191, dated December 22, 2004, to ensure the continued airworthiness of these airplanes in France.

FAA's Determination and Requirements of the Proposed AD

This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. We have examined the DGAC'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 in “Differences Between the Proposed AD, the Service Bulletin, and the French Airworthiness Directive.”

Differences Between the Proposed AD, the Service Bulletin, and the French Airworthiness Directive

The French airworthiness directive and the service bulletin specify to contact the manufacturer for an approved solution for repairing discrepancies found during the internal inspection; and do not specify that repairs are required if discrepancies are found during the external inspection. This proposed AD would require repairing those conditions using a method that we or the DGAC (or its delegated agent) approve. 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 we or the DGAC approve would be acceptable for compliance with this proposed AD.

The French airworthiness directive and the service bulletin specify to submit certain information to the manufacturer, this proposed AD does not include that requirement.

Clarification of Inspection Language

The French airworthiness directive and the service bulletin specify doing a detailed visual inspection for discrepancies. In this proposed AD we refer to this inspection as a “detailed inspection.” Note 1 of this proposed AD defines a detailed inspection.

Costs of Compliance

This proposed AD would affect about 14 airplanes of U.S. registry. The proposed actions would take about 6 work hours per airplane if the internal borescopic inspection method is chosen, and about 44 work hours per airplane if the internal detailed inspection method (with the leading edge removed) is chosen. Both estimates include the time necessary for the external detailed inspection. The average labor rate is $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is between $5,460 and $40,040, or either $390 or $2,860 per airplane.

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):

Aerospatiale: Docket No. FAA-2006-23816; Directorate Identifier 2005-NM-247-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by March 10, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Aerospatiale Model ATR42-200, -300, -320, and -500 airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from a report of cracking on the upper skin and ribs of the outer wing box on an in-service airplane. We are issuing this AD to detect and correct discrepancies (e.g., cracking, loose/sheared fasteners, distortion) of the upper skin and rib feet of the outer wing boxes, which could result in reduced structural integrity 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.

External Inspection and Repair

(f) Before the accumulation of 4,000 total flight cycles, or within 3 months after the effective date of this AD, whichever is later: Do an external detailed inspection for discrepancies of the upper skin panels of the outer wing box on the left and right wing, from rib 24 to rib 29. Do the inspection in accordance with Part A of the Accomplishment Instructions of Avions de Transport Regional Service Bulletin ATR42-57-0064, dated December 16, 2004.

(1) If any discrepancy is found: Before further flight, do the actions in paragraphs (f)(1)(i) and (f)(1)(ii) of this AD.

(i) Repair using a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the Direction Geénérale de l'Aviation Civile (DGAC) (or its delegated agent).

(ii) Do the internal inspection in accordance with paragraph (g) of this AD.

(2) If no discrepancy is found: Within 4 months after doing the external detailed inspection, do the internal inspection in accordance with paragraph (g) 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 mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Internal Inspection and Repair

(g) At the applicable time specified in paragraph (f)(1)(ii) or (f)(2) of this AD: Inspect for discrepancies of the rib feet from rib 24 to rib 29 using one of the inspection methods specified in paragraph (g)(1) or (g)(2) of this AD. Do the inspection in accordance with Part B of the Accomplishment Instructions of Avions de Transport Regional Service Bulletin ATR42-57-0064, dated December 16, 2004. If any discrepancy is found during any inspection required by this paragraph: Before further flight, repair using a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the DGAC (or its delegated agent).

(1) A borescopic inspection through access doors.

(2) A detailed inspection after removing the leading edge of the wing.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, 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

(i) French airworthiness directive F-2004-191, dated December 22, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on January 30, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.