AD 98-24-29

This amendment adopts a new airworthiness directive (AD) that applies to all Aerostar Aircraft Corporation (Aerostar) PA-60-600 and PA-60-700 series airplanes. This AD requires repetitively inspecting the forward face of each wing s 55-percent upper spar cap for cracks above the main landing gear fitting in the top of the wheel well, and replacing or repairing any cracked upper spar cap. Reports of spanwise cracks in the area above the main landing gear attachment on two of the affected airplanes prompted this action. The actions specified by this AD are intended to detect and correct fatigue cracking of the wing upper spar cap, which could result in structural failure of the wing spar to the point of failure with consequent loss of control of the airplane.

Final rule.

98-24-29 AEROSTAR AIRCRAFT CORPORATION: Amendment 39-10916; Docket No. 97-CE-139-AD.

Applicability: All serial numbers of the following airplane models, certificated in any category:

PA-60-600 (Aerostar 600)
PA-60-601 (Aerostar 601)
PA-60-601P (Aerostar 601P)
PA-60-602P (Aerostar 602P)
PA-60-700P (Aerostar 700P)

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 request should include specific proposed actions to address it.

Compliance: Required as indicated in the body of this AD, unless already accomplished.

To detect and correct fatigue cracking of the wing upper spar cap, which could result in structural failure of the wing spar to the point of failure with consequent loss of control of the airplane, accomplish the following:

(a) 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, inspect the forward face of each wing's 55-percent upper spar cap for cracks above the main landing gear fitting in the top of the wheel well. Accomplish this inspection in accordance with the INSTRUCTIONS section of Aerostar Service Bulletin SB600-132, dated September 3, 1997. The initial inspection must be accomplished using dye penetrant methods and all subsequent inspections must be, at the very least, visual inspections.

(b) If any crack(s) is/are found during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD (below):

(1) Replace the upper spar cap in accordance with the applicable maintenance manual, and continue to repetitively inspect as required by paragraph (a) of this AD; or

(2) Obtain a repair scheme from the manufacturer through the FAA, Small Airplane Directorate, at the address specified in paragraph (d) of this AD; incorporate this scheme; and continue to repetitively inspect as required by paragraph (a) of this AD, unless specified differently in the instructions to the repair scheme.

(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, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW, Renton, Washington 98055-4056. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

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

(e) The inspections required by this AD shall be done in accordance with Aerostar Service Bulletin SB600-132, dated September 3, 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 the Aerostar Aircraft Corporation, 10555 Airport Drive, Coeur d'Alene Airport, Hayden Lake, Idaho 83835-9742. 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.

(f) This amendment becomes effective on January 8, 1999.

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 all Aerostar PA-60-600 and PA-60-700 series airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on August 21, 1998 (63 FR 44818). The NPRM proposed to require repetitively inspecting the forward face of each wing s 55-percent upper spar cap for cracks above the main landing gear fitting in the top of the wheel well, and replacing or repairing any cracked upper spar cap.

Accomplishment of the proposed inspections as specified in the NPRM would be required in accordance with Aerostar Service Bulletin SB600-132, dated September 3, 1997. Accomplishment of the proposed repair (if necessary) would be required in accordance with an FAA-approved repair scheme. Accomplishment of the proposed replacement (if necessary) would be required in accordance with the applicable maintenance manual.

The NPRM was the result of reports of spanwise cracks in the area above the main landing gear attachment on two of the affected airplanes.

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 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.

Cost Impact
The FAA estimates that 600 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. Based on these figures, the total cost impact of the initial inspection specified in this AD on U.S. operators is estimated to be $72,000, or $120 per airplane.

These figures only take into account the costs of the initial inspection and do not take into account the costs of repetitive inspections and the costs associated with any repair that will be necessary if cracks are found. The FAA has no way of determining the number of repetitive inspections an owner/operator will incur over the life of the airplane, or the number of airplanes that will need replacement or repair.

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 FederalAviation 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 a new airworthiness directive (AD) to read as follows: