RULES and REGULATIONS

DEPARTMENT OF TRANSPORTATIONc 14 CFR Part 39 [Docket No. 90 -NM - 217 - AD; Amdt. 39 - 7032; AD 91 - 13 - 01] Airworthiness Directives; Airbus Industrie Model A310 - 200 Series Airplanes Monday, June 10, 1991 AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This amendment adopts a ne w airworthiness directive (AD), applicable to certain Airbus Industrie Model A310 - 200 series airplanes, which requires repetitive visual inspections to detect cracks in a certain frame reinforcement angle runout; and repair, if necessary. This amendment also provides for terminating action for the repetitive inspections. This amendment is prom pted by full scale fatigue testing by the manufacturer whi ch revealed cracks in Frame 46 between Stringer 21 and Stringer 22. This condition, if not corrected, could result in reduced structural integrity of the fuselage. EFFECTIVE DATE: July 15, 1991. ADDRESSES: The applicable service information may be obtained from Airbus Industrie, Airbus Support Division, Avenue Didier Daurat, 31700 Blagnac, France. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW. , Renton, Washington. FOR FURTHER INFORMATION CONTACT: Mr. Greg Holt, Standardization Branch, ANM - 113; telephone (206) 227 - 2140. Mailing address: FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S W., Renton, Washington 98055 - 4056. SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations to include a new airworthiness directive, applicable to certain Airbus Industrie Model A310 - 200 series airplanes, which requires repetitive visual inspections to detect cracks in a certain frame reinforcement angle runout; repair, if nece ssary; and reinforcement of the angle runout; was published in the Federal Register on Decem ber 20, 1990 (55 FR 52177) . Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. One commenter noted that the applicability statement of the AD should apply to Model A310 - 200 series airplanes with serial num

bers 162 through 357, inclusive, since the first manufacturer's serial number was 162. The FAA concurs. The applicability statement has been changed accordingly. Two commenters objected to mandating the modification addressed in Airbus Industrie Service Bulletin A310 - 53 - 2019, and suggested that the proposed requirement to install the modification be deleted. The commenters stated that the inspections specified in Service Bulletin A310 - 53 - 2054 are adequate to ensure the continue d structural airworthiness of the airplanes. Furthermore, the commenters stated that cracking had occurred only during fatigue testingand has not occurred on in - service airplanes. The commenters further noted that milling required to accomplish the

mo dification has a very high risk factor; and that there would be a high probability that the reinforcement angle runout wo uld be damaged and wo uld require extensive repair or replacement. One of these co mmenters, Airbus Industrie, stated that, in view of the ease of inspecting this area, any damage that might occur would be easily detected. The FAA concurs. Upon further review of the proposed inspection criteria and interval, the FAA has determined that the structural integrity of the airplane can be assured with the continued inspection of the frame rein forcement angle runout because (1) the inspections are easily performed, (2) the area is easily accessible, and (3) the required inspections will likely detect damage in a timely manner, before failure could occur. Therefore, the final rule has been revised to delete the modification requirement. The final rule continues to provide for the optional modification of the reinforcement angle runout by tapering the angle and reducing the thickness; once this is acco m plished, the required repetitive inspections may be terminated. The economic analysis paragraph below has been revised to reflect only the cost for the repetitive inspections. Since the proposed mandatory modification requirement has been deleted from the final rule, related parts cost have also been deleted from the economic analysis. The economic analysis paragraph has also been revised to increase the specified hourly labor rate from $40 per manhour (as was cited in the preamble to the Notice) to $55 per manhour. The FAA has determined that it is nece ssary to increase this rate used in calculating the cost impact associated with AD activity to account for various infl ationary costs in the airline industry. Paragraph C. of the final rule has been revised to specify the current procedure for submitting requests for approval of alternative methods compliance. After careful review

o f the available data, including the comment noted above, the FAA has determined that air saf ety and the public interest require the adoption of the rule with the changes noted above. These changes will ne ither significantly increase the economic burden on affected operators nor increase the scope of the final rule. It is estimated that 7 airplanes of U.S. registry will be affected by this AD, that it will take approximately 22 manhours per airplane to accom plish the required actions, and that the average labor cost will be $55 per manhour. Based on these f

igures, the total cost impact of the AD on U.S. operators is estimated to be $8,470. 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 p ower 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 prep aration of a Federalism Asses s ment. For the reasons discussed above, I certify that this action: (1) Is not a “major rule” under Executive Order 12291; (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 final evaluation has been prepared for this action and is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. Adoption of the Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 of the Federal Aviation Regulations as follows:PART 39

— [AMENDED]1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 1354(a), 1421 and 1423 ; 49 U.S.C. 1 06(g) (Revised Pub. L. 97 -449, Jan uary 12, 1983); and 14 CFR 11.89. § 39.13 [Amended] 14 CFR § 39.13 2. Section 39.13 is amended by adding the following ne w airworthiness directive: 91 - 13 - 01. Airbus Industrie: Amendment 39 - 7032. Docket No. 90 -NM - 217 -AD. Applicability: Model A310 - 200 series airplanes, Serial Numbers 162 through 357, certificated in any category. Com pliance: Required as indicated, unless previously accomplished. To prevent reduced structural integrity of the fuselage, accomplish the following: A. Prior to the accumulation of 12,000 landings, or within 2,000 landings after the effective date of this AD, whic hever occurs later, and thereafter at intervals not to exceed 3,000 landings, perform a visual inspection of Frame 46 at the level of the frame reinforcement angle runout between Stringer 21 and Stringer 22 (left and right), in accordance with Airbus Industrie Service Bulletin A310 - 53 - 2054, Revision 2, dated May 22, 1990. If cracks are found, prior to further flight, repair in accordance with the service bulletin. B. Modification of the reinforcement angle runout by tapering the angle and reducing the thickness, in accordance with Airbus Industrie Service Bulletin A310 - 53 - 2019, Revision 2, dated May 22, 1990, constitutes terminating action for the repetitive inspections required by paragraph A. of this AD. C. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM - 113, FAA, Transport Airplane Directorate. Note: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or co mment and then send it to the Manager, Standardization Branch, ANM - 113. D. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. All persons affected by

this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Airbus Industrie, Airbus Support Division, Avenue Didier Daurat, 31700 Blagnac, France. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington.This amendment (39 - 7032 , AD 91 - 13 - 01 ) becomes effective July 15, 1991.

Issued in Renton, Washington, on May 30, 1991. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 91 - 13647 Filed 6 - 7 - 91; 8:45 am] 56 FR 26602 - 01