AD 96-24-04

This amendment adopts a new airworthiness directive (AD) that applies to Aerospace Technologies of Australia (ASTA) Nomad Models N22B, N22S, and N24A airplanes. This action requires repetitively inspecting the tailplane stabilizer center section and repairing any cracked tailplane structure. This AD also provides an optional modification as a terminating action, after an inspection in which no cracks are found. A tailplane failure on one of the affected airplanes prompted this action. The actions specified by this AD are intended to prevent cracking in the stabilizer center section, which, if not detected and corrected, could result in tailplane failure and loss of control of the airplane.

Final rule.

96-24-04 AEROSPACE TECHNOLOGIES OF AUSTRALIA (ASTA): Amendment 39-9830; Docket No. 95-CE-75-AD.

Applicability: Nomad Models N22B, N22S, and N24A airplanes (all serial numbers), certificated in any category, that have not incorporated ASTA Modification N663 and N768 in the area of the tailplane stabilizer.

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 (d) 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 requestshould include specific proposed actions to address it.

Compliance: Required within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished, and thereafter at intervals not to exceed 100 hours TIS.

To prevent cracking in the tailplane stabilizer center section, which, if not detected and corrected, could result in tailplane failure and loss of control of the airplane, accomplish the following:

(a) Inspect the tailplane stabilizer center section and center lightening hole for cracks (using both visual and eddy current methods) in accordance with section "C. Description, (1) Part 1 -- Inspection." of Nomad Service Bulletin (SB) ANMD-55-26, Revision 8, dated April 15, 1994.

(b) If cracks are found during any inspection required by this AD, prior to further flight, repair the stabilizer center section in accordance with a repair scheme obtained from the manufacturer through the Manager, Los Angeles Aircraft Certification Office, at the address specified in paragraph (d).

(1) This repair scheme does not eliminate the repetitive inspection requirement.

(2) The repetitive inspection requirement of this AD may be terminated by incorporating both Modification (Mod.) N663 and N768 in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Nomad SB ANMD-55-26, Revision 8, dated April 15, 1994. These modifications may only be incorporated, prior to further flight, after any inspection, provided no cracks are found.

(3) Modifications N663 and N768 may also be incorporated as terminating action to the repetitive inspections of this AD on airplanes that have cracks repaired in the tailplane stabilizer center section provided the modifications are incorporated, prior to further flight, after an inspection where no cracks were found.

NOTE 2: Mod. N663 reworks the horizontal stabilizer to incorporate a strengthened main spar assembly that includes a gust stop spring box and modified mass balance arm. The trim tab hinges are moved 0.17 inches aft and farings are added to the bottom skin of the horizontal stabilizer to permit increased trim tab movement. Mod. N768 incorporates Mod. N663 and replaces the pivot brackets, attachment bolts, and spar web doubler with strengthened components.

(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) 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, Los Angeles Aircraft Certification Office, FAA, 3960 Paramount Blvd., Lakewood, California. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles Aircraft Certification Office.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.

(e) The inspections, modifications, and replacements required by this AD shall be done in accordance with Nomad Service Bulletin ANMD-55-26, Revision 8, dated April 15, 1994. 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 AeroSpace Technologies of Australia, Limited, ASTA DEFENCE, Private Bag No. 4, Beach Road Lara 3212, Victoria, Australia. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief 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.

(f) This amendment becomes effective on January 17, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to ASTA Nomad Models N22B, N22S, and N24A airplanes was published in the Federal Register on March 22, 1996 (61 FR 11784). The action proposed to require inspecting (using both visual and eddy current methods) the tailplane stabilizer center section for cracks, and prior to further flight, repairing any cracked tailplane stabilizer center section for these ASTA airplanes that do not have Modifications N663 and N768 incorporated in the area of the tailplane stabilizer center section. This AD also provides the option of modifying the tailplane stabilizer center section (Mod. N663 and N768) as a terminating action.

Applicable Service Information
Accomplishment of the proposed action would be in accordance with Nomad Service Bulletin ANMD-55-26, Revision 8, dated April 15, 1994.

Comments
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.

FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the 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.

Costs Impact
The FAA estimates that 15 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 15 workhours per airplane to accomplish this action, and that the average labor rate is approximately $60 an hour. The total cost impact of this AD upon U.S. operators of the affected airplanes is estimated to be $13,500 or $900 per airplane. This figure only includes the cost for the initial inspection and does not include replacement costs if the tailplane stabilizer center section is found cracked, nor does it include repetitive inspection costs. Additionally, the FAA has no way of determining how many tailplane stabilizer center sections may be cracked or how many repetitive inspections each owner/operator may incur over the life of the airplane.

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 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 USC 106(g), 40113, 44701.Section 39.13 - [AMENDED]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: