AD 98-08-08 ACTIVE

This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR42-500 series airplanes. This action requires a one-time inspection to verify the installation of certain stringer clips at the junction of frame 34 and stringer 6, and installation of stringer clips, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent fatigue cracking in the skin of the fuselage, which could result in loss of pressure inside the airplane.

Final rule; request for comments.

98-08-08 AEROSPATIALE: Amendment 39-10457. Docket 98-NM-107-AD.

Applicability: Model ATR42-500 series airplanes, as listed in Aerospatiale Service Bulletin ATR42-53-0103, dated September 23, 1996; certificated in any category.

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 fatigue cracking in the skin of the fuselage, which could result in loss of pressure inside the airplane, accomplish the following:

(a) Within 3,000 flight cycles after the effective date of this AD, perform a one-time visual inspection to verify the installation of stringer clips at the junction of frame 34 and stringer 6, on the left and right side of the airplane.

(1) If the stringer clips have been installed, no further action is required by this AD.

(2) If any stringer clip has not been installed, prior to further flight, install the stringer clip, in accordance with Aerospatiale Service Bulletin ATR42-53-0103, dated September 23, 1996.

(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, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(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.

(d) The installation shall be done in accordance with Aerospatiale Service Bulletin ATR42-53-0103, dated September 23, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in French airworthiness directive 96-132-065(B), dated July 3, 1996.

(e) This amendment becomes effective on April 27, 1998.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Aerospatiale Model ATR42-500 series airplanes. The DGAC advises that the manufacturer has reported that certain stringer clips were not installed during production on several in-service airplanes. The stringer clips are missing at the junction of frame 34 and stringer 6 of the fuselage. Without the installation of these clips, fatigue cracking may occur in the skin of the fuselage. This condition, if not corrected, could result in a loss of pressure inside the airplane.

Explanation of Relevant Service Information
The manufacturer has issued Aerospatiale Service Bulletin ATR42-53-0103, dated September 23, 1996, which describes procedures for installing stringer clips at the junction of frame 34 and stringer 6, on the left and right side of the airplane. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The DGAC classified this service bulletin as mandatory and issued French airworthiness directive 96-132-065(B), dated July 3, 1996, in order to assure the continued airworthiness of these airplanes in France.

FAA's Conclusions
This airplane model is manufactured in France 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, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, 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 the Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent fatigue cracking in the skin of the fuselage, which could result in loss of pressure inside the airplane. This AD requires accomplishment of the actions specified in the service bulletin described previously, except as described below.

Differences Between This AD, Foreign Airworthiness Directive, and Service Bulletin
Operators should note that this AD differs from procedures described in the foreign airworthiness directive and the service bulletin in that it requires a one-time inspection to verify whether installation of the stringer clips at the junction of frame 34 and stringer 6 has been accomplished, and installation of the stringer clips on the condition that the clips are not already installed. The foreign airworthiness directive and the service bulletin specify only that the stringer clips be installed at the junction offrame 34 and stringer 6. The FAA has determined that because the possibility exists that installation of stringer clips at the junction of frame 34 and stringer 6 has already been accomplished, before installing stringer clips, operators should first conduct an inspection of the junction of frame 34 and stringer 6 to ensure that installation of such clips has not already been accomplished.

Cost Impact
None of the airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future.

Should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 6 work hours to accomplish the installation, if necessary, 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 this AD would be $360 per airplane.

Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, prior notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.

Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-107-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by Reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-107-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

The service information referenced in this AD may be obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.