AD 2000-05-23

This amendment adopts a new airworthiness directive (AD) that applies to all Ayres Corporation (Ayres) S2R series airplanes that are equipped with at least one main landing gear fuselage attach bolt with a grease fitting installed through the shank. This AD requires replacing the main landing gear fuselage attach bolts that are drilled with a grease fitting with undrilled (no grease access) attach bolts. This AD is the result of a report of cracks found in all four main landing gear fuselage attach bolts on one of the affected airplanes. The actions specified by this AD are intended to prevent collapse of the main landing gear caused by cracked main landing gear fuselage attach bolts, which could result in main landing gear collapse with possible wing fuel tank rupture and consequent fire

Final rule

2000-05-23 AYRES CORPORATION: Amendment 39-11633; Docket No. 99-CE-57-AD.
Applicability: The following airplane models, all serial numbers, certificated in any category, that have at least one main landing gear fuselage attach bolt (that is drilled with a grease fitting), part number 21418T001 or 21418T005 (or FAA-approved equivalent part number):

Models
S-2R, S2R-G1, S2R-G5, S2R-G6, S2R-G10, S2R-R3S, S2R-T11, S2R-T15, S2R-T34, S2R-T45, S2R-T65, S2R-R1340, S2R-R1820, S2RHG-T34, and S2RHG-T65.

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 prevent collapse of the main landing gear caused by cracked main landing gear fuselage attach bolts, which could result in main landing gear collapse with possible wing fuel tank rupture and consequent fire, accomplish the following:

(a) Within the next 100 hours time-in-service (TIS) after the effective date of this AD, replace each main landing gear fuselage attach bolt that is drilled with a grease fitting with an undrilled (no grease access) attach bolt, part number AN10-33 or NAS6610-42D (or FAA-approved equivalent part number). Accomplish this replacement in accordance with both Ayres Service Bulletin No. SB-AG-42, dated June 16, 1999, and the applicable maintenance manual.

(b) As of the effective date of this AD, no person may install, on any affected airplane, a main landing gear fuselage attach bolt (that is drilled with a grease fitting), part number 21418T001 or 21418T005 (or FAA-approved equivalent part number).

(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 compliance times that provides an equivalent level of safety may be approved by the Manager, Atlanta Aircraft Certification Office (ACO), One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO.

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

(e) The replacements required by this AD shall be done in accordance with Ayres Service Bulletin No. SB-AG-42, dated June 16, 1999. 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 Ayres Corporation, P.O. Box 3090, One Ayres Way, Albany, Georgia 31706-3090. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, 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 May 5, 2000.

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 Ayres S2R series airplanes of the same type design, that are equipped with at least one main landing gear fuselage attach bolt with a grease fitting installed through the shank, was published in the Federal Register as a notice of proposed rulemaking (NPRM) on November 24, 1999 (64 FR 66116). The NPRM proposed to require replacing the main landing gear fuselage attach bolts that are drilled with a grease fitting with undrilled (no grease access) attach bolts. Accomplishment of the proposed action as specified in the NPRM would be required in accordance with both Ayres Service Bulletin No. SB-AG-42, dated June 16, 1999, and the applicable maintenance manual.

The NPRM was the result of a report of cracks found in all four main landing gear fuselage attach bolts on one 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.

Differences Between the Service Bulletin and this AD
Ayres Service Bulletin No. SB-AG-42, dated June 16, 1999, specifies repetitive inspections and repetitive replacements of the main landing gear fuselage attach bolts. The FAA does not have justification to mandate the repetitive inspections and repetitive replacements.

Based on all available information, the FAA has determined that initially replacing the main landing gear fuselage attach bolts with attach bolts of improved design will correct the unsafe condition on the affected airplanes.

Cost Impact
The FAA estimates that 1,000 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 4 workhours per airplane to accomplish the replacement, and that the average labor rate is approximately $60 an hour. Parts cost approximately $88 per airplane (4 bolts per airplane at $22 each). Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $328,000, or $328 per airplane.

Regulatory Impact
The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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 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: