AD 98-09-22

This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR42-200, -300, and -320 series airplanes, that requires an inspection to detect fatigue cracking of the windshield frame structure, and modification of the windshield frame structure. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent reduced structural integrity of the airplane resulting from fatigue cracking of the windshield frame structure.

Final rule.

98-09-22 AEROSPATIALE: Amendment 39-10503. Docket 97-NM-303-AD.

Applicability: Model ATR42-200, -300, and -320 series airplanes, on which Aerospatiale Modification 01392 has not been installed, certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 reduced structural integrity of the airplane resulting from fatigue cracking of the windshield frame structure, accomplish the following:

(a) Prior to the accumulation of 24,000 total flight cycles, or within 60 days after the effective date of this AD, whichever occurs later: Inspect to detect cracking of the windshield frame structure in accordance with Operation Description (B - Inspection) of the Accomplishment Instructions of Aerospatiale Service Bulletin ATR42-53-0093, Revision 1, or ATR42-53-0094, Revision 2, both dated February 19, 1996.

(1) If the inspection reveals no crack, or reveals cracking that does not exceed the specifications listed in Figure 6, Sheet 1, of Service Bulletin ATR42-53-0093, Revision 1, dated February 19, 1996: Prior to further flight, modify the windshield frame structure in accordance with either service bulletin.

(2) If the inspection reveals any crack that exceeds the specifications in Figure 6, Sheet 1, of Service Bulletin ATR42-53-0093, Revision 1, dated February 19, 1996, but does not exceed the cut-out areas specified in Figure 7, Sheet 1, of Service Bulletin ATR42-53-0094, Revision 2, dated February 19, 1996: Prior to further flight, modify the windshield frame structure in accordance with Service Bulletin 42-53-0094, Revision 2, dated February 19, 1996.

(3) If the inspection reveals any crack that exceeds the cut-out areas specified in Figure 7, Sheet 1, of Service Bulletin ATR42-53-0094, Revision 2, dated February 19, 1996: Prior to further flight, modify the windshield frame structure in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate.

NOTE 2: Accomplishment of the modifications specified in ATR Service Bulletin ATR42-53-0093, Revision 1, or ATR42-53-0094, Revision 2, both dated February 19, 1996, is not equivalent to accomplishment of Aerospatiale Modification 01392. Therefore the ATR42 Time Limits Document inspection items with "PRE MOD 1392" effectivity are still applicable for airplanes modified by either of the previously described service bulletins.

(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 3: 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 the following Aerospatiale Service Bulletins, which contain the specified effective pages:

Service Bulletin
Referenced and Date
Page Number
Shown on Page
Revision Level
Shown on Page
Date
Shown on Page
ATR42-53-0093,
Revision 1,
February 19, 1996
1-4, 13

5-12, 14-41
1

Original
February 19, 1996

April 26, 1995
ATR42-53-0094,
Revision 2,
February 19, 1996
1, 2, 8, 9, 16, 18,
39, 40, 48, 53, 54

3, 4, 7, 10-15,
17, 19-24, 26, 27,
29-32, 34-38, 47,
55, 56

5, 6, 25, 28, 33,
41-46, 49-52
2

1

Original
February 19, 1996

May 29, 1995

April 24, 1995

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 4: The subject of this AD is addressed in French airworthiness directive 95-126-061(B), dated June 21, 1995.

(e) This amendment becomes effective on June 3, 1998.

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 ATR42-200, -300, and -320 series airplanes was published in the Federal Register on February 19, 1998 (63 FR 8373). That action proposed to require an inspection to detect fatigue cracking of the windshield frame structure, and modification of the windshield frame structure.

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.

The commenter supports the proposed rule.

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 as proposed.

Cost Impact
The FAA estimates that 106 airplanes of U.S. registry will be affected by this AD.

It will take approximately 19 work hours per airplane to accomplish the required inspection, at an average labor rate of $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 $120,840, or $1,140 per airplane.

It will take approximately 191 work hours per airplane to accomplish the required modification specified in Aerospatiale Service Bulletin ATR42-53-0093, Revision 1, dated February 19, 1996, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of this modification on U.S. operators is estimated to be $11,460 per airplane.

It will take approximately 281 work hours per airplane to accomplish the required modification specified in Aerospatiale Service Bulletin ATR42-53-0094, Revision 2, dated February 19, 1996, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of this modification on U.S. operators is estimated to be $16,860 per airplane.

The cost impact figures discussed above are 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 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: