AD 99-04-24

This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR72 series airplanes, that requires a one-time inspection to detect damage of certain anchor nuts located on the upper surface of the wings, and replacement of the anchor nuts with new or serviceable nuts, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of anchor nuts on the upper surface of the wings, which could result in reduced structural integrity of the airplane.

Final rule

99-04-24 AEROSPATIALE: Amendment 39-11049. Docket 98-NM-118-AD.

Applicability: Model ATR72-102, -201, -202, and -212 series airplanes; as listed in Avions de Transport Regional Service Bulletin ATR72-57-1019, dated July 7, 1997; 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 failure of anchor nuts on the upper surface of the wings, which could result in reduced structural integrity of the airplane, accomplish the following:

(a) Within 6 months after the effective date of this AD, inspect the anchor nuts, having part number (P/N) NAS1473A5, located on the upper surface of the wing to detect damage, in accordance with Avions de Transport Regional Service Bulletin ATR72-57-1019, dated July 7, 1997, or Revision 1, dated May 12, 1998.

(1) If no damage is detected, no further action is required by this AD.

(2) If any damage is detected, and the damage is within the allowable limits specified in the Accomplishment Instructions of the service bulletin, prior to the accumulation of an additional 4,000 flight cycles following the inspection, replace the damaged nut having P/N NAS1473A5 with a new or serviceable nut, in accordance with the AccomplishmentInstructions of the service bulletin.

(3) If any damage is detected, and the damage is outside the allowable limits specified in the Accomplishment Instructions of the service bulletin, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Direction G n rale de l'Aviation Civile (or its delegated agent).

(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. Operators shall submit their requests 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 actions shall be done in accordance with Avions de Transport Regional Service Bulletin ATR72-57-1019, dated July 7, 1997, or Avions de Transport Regional Service Bulletin ATR72-57-1019, Revision 1, dated May 12, 1998, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date Shown
on Page
1-7, 10, 12, 13, 17
1
May 12, 1998
8, 9, 11, 14-16
Original
July 7, 1997

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 97-264- 034(B), dated September 24, 1997.

(e) This amendment becomes effective on March 30 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Aerospatiale Model ATR72 series airplanes was published in the Federal Register on June 4, 1998 (63 FR 30425). That action proposed to require a one-time inspection of certain anchor nuts located on the upper surface of the wings to detect damage, and replacement of the anchor nuts with new or serviceable nuts, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received.

Request to Reference Latest Service Bulletin
The commenter requests that the proposed AD be revised to reference Avions de Transport Regional Service Bulletin ATR72-57-1019, Revision 1, dated May 12, 1998, as an additional source of service information for accomplishment of the actions specified inthe proposal. The commenter states that Revision 1 is essentially identical to the original issue, which was cited as the appropriate source of service information for accomplishment of the actions specified in the proposed AD, and merely adds additional explanations and editorial corrections that do not affect the airplanes already inspected and repaired in accordance with the original service bulletin.

The FAA concurs with the commenter s request to reference the latest service bulletin. The FAA has reviewed Revision 1 of the service bulletin and finds it is an acceptable method of compliance for accomplishment of the actions required by this AD. The final rule has been revised accordingly.

Conclusion
After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 39 airplanes of U.S. registry will be affected by this AD, that it will take approximately 8 work hours per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $18,720, or $480 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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 delegatedto 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: