AD 2017-23-04

This AD is effective December 20, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of December 20, 2017.

For service information identified in this final rule, contact Airbus SAS, Airworthiness Office—EAW, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email account.airworth-eas@airbus.com; Internet http://www.airbus.com. You may view this referenced service information at the FAA, Transport Standards Branch, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0710.

Dan Rodina, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; telephone 425-227-2125; fax 425-227-1149.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus Model A300 B4-600R series airplanes; Model A300 B4-603, B4-620, and B4-622 airplanes; Model A300 C4-605R Variant F airplanes; and Model A300 F4-605R airplanes. The NPRM published in the Federal Register on July 27, 2017 (82 FR 34885) (“the NPRM”). The NPRM was prompted by a determination that the top stringer joints at rib 18 are an area of uniform stress distribution, which indicates that cracks may develop in adjacent stringers at the same time. The NPRM proposed to require an inspection of the upper wing skin and top stringer joints, and modification of the stringer joint couplings if necessary. We are issuing this AD to detect and correct damage (including cracking) at the stringer joints, which could reduce the structural integrity of the wing.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2017-0023, dated February 10, 2017 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for certain Airbus Model A300 B4-600R series airplanes; Model A300 B4-603, B4-620, and B4-622 airplanes; Model A300 C4-605R Variant F airplanes; and Model A300 F4-605R airplanes. The MCAI states:

In response to the FAA Part 26 rule change concerning Widespread Fatigue Damage (WFD), all wing structural items of the A300-600 design deemed potentially susceptible to WFD were assessed. The top stringer joints at Rib 18 were highlighted as an area of uniform stress distribution, indicating that cracks may develop in adjacent stringers at the same time which is known as Multi Element Damage (MED). Each affected stringer joint consists of three main load transferring parts: An overlapping flange, two straps attached through the stringer web and a strap on the top flange. All the components of the joint are attached with fasteners. The fastener holes were the subject of a MED WFD analysis, which showed that cracking could occur from a number of the holes in the joint on stringers 11, 12, 13, 14, 15, 16, 17, and 18.

This condition, if not detected and corrected, could reduce the structural integrity of the wing.

Prompted by the conclusion of the WFD analysis, Airbus issued Service Bulletin (SB) A300-57-6118 to provide modification instructions. The modification will both re-life via oversizing and inspect via non-destructive test a defined number of stringer joint fastener holes at Rib 18. This modification will delay the onset of cracking at the stringer joint, providing it is completed at the specified time and will delay the requirement for subsequent inspection.

For the reasons described above, this [EASA] AD requires a detailed visual inspection (DVI) [for damage, including cracking] of the upper wing skin and the top stringer joints at Rib 18, [and corrective action if necessary] and modification of the stringer joint couplings at Rib 18, on both wings [as applicable].

The modification includes a related investigative action, i.e., a special detailed (roto-probe) inspection for damage, including cracking, of the fastener holes in the upper wing skin, and corrective action if necessary. Corrective actions include repairing any damage.

You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0710.

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment.

FedEx supported the intent of the NPRM, but requested that we update the parts cost in the Costs of Compliance section of the proposed AD to reflect the cost of two parts kits. FedEx noted that the proposed AD listed the parts cost for only one kit. FedEx pointed out that operators may need to modify both wings and could therefore need two parts kits per airplane.

We agree with the commenter's request. We have revised the Costs of Compliance section of this final rule to reflect two parts kits, each costing $4,770.

Airbus requested that we correct a reference to “Airbus Model A300 C4-605 Variant F” airplanes in paragraph (g)(2) of the proposed AD. The correct model name is “A300 C4-605R Variant F” airplanes.

We agree with the commenter's request. We have corrected the typographical error in this AD.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Airbus has issued Service Bulletin A300-57-6118, Revision 01, dated January 31, 2017. This service information describes procedures for an inspection of the upper wing skin and top stringer joints at rib 18, and modification of the stringer joint couplings. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

We estimate that this AD affects 65 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

We have received no definitive data that will allow us to provide cost estimates for certain on-condition actions specified in this AD.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

We determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that this AD:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);

3. Will not affect intrastate aviation in Alaska; and

4. 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):