AD 96-12-03 R2

This amendment revises Airworthiness Directive (AD) 96-12-03 R1, which applies to Aviat Aircraft, Inc. (Aviat) Models S-1S, S-1T, S-2, S-2A, S-2S, and S-2B airplanes that are equipped with aft lower fuselage wing attach fittings incorporating part number (P/N) 76090, P/N 2-2107-1, or P/N 1-210-102. AD 96-12-03 R1 currently requires repetitively inspecting the aft lower fuselage wing attach fitting on both wings for cracks, and modifying any cracked aft lower fuselage wing attach fitting. Modifying both aft lower fuselage wing attach fittings eliminates the repetitive inspection requirement of AD 96-12-03. Aviat started incorporating modified aft lower fuselage wing attach fittings on newly manufactured airplanes beginning with serial number 5337, instead of 5349 as referenced in the existing AD. This AD retains the repetitive inspection and possible modification requirements of AD 96-12-03 R1, and will change the applicability accordingly. The actions specified by this AD are intended to prevent possible in-flight separation of the wing from the airplane caused by a cracked fuselage wing attach fitting.

Final rule.

96-12-03 R2 AVIAT AIRCRAFT, INC.: Amendment 39-10805; Docket No. 96-CE-23-AD; Revises AD 96-12-03 R1, Amendment 39-10109.

Applicability: The following airplane models and serial numbers, certificated in any category, that are equipped with aft lower fuselage wing attach fittings incorporating part number (P/N) 76090, P/N 2-2107-1, or P/N 1-210-102, and where these aft lower fuselage wing attach fittings on both wings have not been modified in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of one of the following service bulletins (SB):

Service Bulletins

Aviat SB No. 25, dated April 3, 1996, Revised: November 12, 1996, Revised: November 11, 1997;

Aviat SB No. 25, dated April 3, 1996, Revised: November 12, 1996; or

Aviat SB No. 25, dated April 3, 1996.

Airplanes Affected

Models S-1S, S-1T, S-2, S-2A, and S-2S airplanes, all serial numbers.

Model S-2B airplanes, serial numbers 5000 through 5336.

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 (e) 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 in the body of this AD.

To prevent possible in-flight separation of the wing from the airplane caused by a cracked aft lower fuselage wing attach fitting, accomplish the following:

(a) Within 50 hours time-in-service (TIS) after October 3, 1997 (the effective date of AD 96-12-03 R1), unless already accomplished (compliance with either AD 96-12-03 R1 or AD 96-12-03), and thereafter at intervals not to exceed 50 hours TIS, inspect the aft lower fuselage wing attach fitting on both wings for cracks. Accomplish these inspections in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of one of the following SB's:

(1) Aviat SB No. 25, dated April 3, 1996, Revised: November 12, 1996, Revised: November 11, 1997;

(2) Aviat SB No. 25, dated April 3, 1996, Revised: November 12, 1996; or

(3) Aviat SB No. 25, dated April 3, 1996.

(b) If any cracked aft lower fuselage wing attach fitting is found during any inspection required by this AD, prior to further flight, modify the cracked aft lower fuselage wing attach fitting in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of one of the SB's referenced in paragraphs (a)(1), (a)(2), and (a)(3) of this AD. Repetitive inspections are no longer necessary on an aft lower fuselage wing attachment fitting that was found cracked and has the referenced modification incorporated.

(c) Modifying the aft lower fuselage wing attach fitting on both wings in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of one of the SB's referenced in paragraphs (a)(1), (a)(2), and (a)(3) of this AD is considered terminating action for the repetitive inspection requirement of this AD.

(d) 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.

(e) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Denver Aircraft Certification Office (ACO) , 26805 E. 68th Avenue, Room 214, Denver, Colorado 80249.

(1) The request shall be forwarded throughan appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Denver ACO.

(2) Alternative methods of compliance approved in accordance with AD 96-12-03 R1 or AD 96-12-03 are considered approved for this AD.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Denver ACO.

(f) The inspections and modifications required by this AD shall be done in accordance with Aviat Service Bulletin No. 25, dated April 3, 1996; Revised: November 12, 1996; Revised: November 11, 1997, Aviat Service Bulletin No. 25, dated April 3, 1996, Revised: November 12, 1996; or Aviat Service Bulletin No. 25, dated April 3, 1996.

(1) The incorporation by reference of Aviat Service Bulletin No. 25, dated April 3, 1996; Revised: November 12, 1996; Revised: November 11, 1997, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFRpart 51.

(2) The incorporation by reference of Aviat Service Bulletin No. 25, dated April 3, 1996, Revised: November 12, 1996, was previously approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of October 3, 1997 (62 FR 44535, August 22, 1997).

(3) The incorporation by reference of Aviat Service Bulletin No. 25, dated April 3, 1996, was previously approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of June 24, 1996 (61 FR 28730, June 6, 1996).

(4) Copies may be obtained from Aviat Aircraft, Inc., P.O. Box 1240, Afton, Wyoming 83110. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(g) This amendment revises AD 96-12-03 R1, Amendment 39-10109.

(h) This amendment becomes effective on November 20, 1998.

Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to Aviat Models S-1S, S-1T, S-2, S-2A, S-2S, and S-2B airplanes that are equipped with aft lower fuselage wing attach fittings incorporating P/N 76090, P/N 2-2107-1, or P/N 1-210-102, was published in the Federal Register as a notice of proposed rulemaking (NPRM) on June 5, 1998 (63 FR 30658). The NPRM proposed to revise AD 96-12-03 R1, which currently requires the following on Aviat Models S-1S, S-1T, S-2, S-2A, S-2S, and S-2B airplanes that are equipped with aft lower fuselage wing attach fittings incorporating P/N 76090, P/N 2-2107-1, or P/N 1-210-102:

- Repetitively inspecting the aft lower fuselage wing attach fitting on both wings for cracks; and

- Modifying any cracked aft lower fuselage wing attach fitting. Modifying both aft lower fuselage wing attach fittings eliminates the repetitive inspection requirement of AD 96-12-03.

The NPRM also proposed to retain the repetitive inspection and possible modification requirements of AD 96-12-03 R1, and would change the applicability of the Model S-2B airplanes from an ending serial number of 5348 to an ending serial number of 5336. Accomplishment of the proposed action as specified in the NPRM would be in accordance with Aviat Service Bulletin No. 25, dated April 3, 1996; Revised: November 12, 1996; Revised: November 11, 1997.

The NPRM was the result of Aviat reporting to the FAA that the ending serial number for the Model S-2B airplanes is incorrect.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety andthe public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Cost Impact
The FAA estimates that 500 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 2 workhours per airplane to accomplish the initial inspection, and that the average labor rate is approximately $60 an hour. Parts to accomplish the inspections cost approximately $100 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $110,000. These figures do not take into account the cost of repetitive inspections. The FAA has no way of determining how many repetitive inspections each owner/operator may incur over the life of each airplane.

AD 96-12-03 R1 currently requires the same actions on the affected airplanes as this AD. The only difference between this AD and AD 96-12-03 R1 is a change in the ending serial number of the Model S-2B airplanes. Therefore, this AD has no additional cost impact over that already required by AD 96-12-03 R1.

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 economicimpact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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 removing Airworthiness Directive (AD) 96-12-03 R1, Amendment 39-10109 (62 FR 44535, August 22, 1997), and byadding a new AD to read as follows: