AD 98-06-08

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A300, A310, and A300-600 series airplanes, that requires inspections to detect defects of the flanges of the bleed air ducts of the auxiliary power unit (APU), and to measure the material thickness of the flanges; and repair, replacement of the duct with a new or serviceable duct, or operation of the airplane with the bleed air system of the APU inoperative, if necessary. For certain airplanes, the amendment also requires an inspection to detect cracks of the flanges, and follow-on actions. This amendment is prompted by issuance of mandatory continued airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent rupturing and cracking of the flanges of the bleed air ducts, which could damage the elevator control system and consequently reduce the controllability of the airplane.

Final rule.

98-06-08 AIRBUS: Amendment 39-10385. Docket 95-NM-278-AD.

Applicability: Model A300, A310, and A300-600 series airplanes on which Airbus Modification 11308 has not been accomplished during manufacture; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (b) 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, unless accomplished previously.

To prevent rupturing and cracking of the flanges of the bleed air ducts of the auxiliary power unit (APU), and cracking of the adjacent duct, which could damage the elevator control system and consequently reduce the controllability of the airplane; accomplish the following:

(a) Prior to the accumulation of 5,000 total flight cycles, or within 500 flight cycles after the effective date of this AD, whichever occurs later: Perform a visual inspection to detect defects (recesses, sharp edges, or scratches) of the inner and outer surfaces of all flanges of the bleed air ducts of the APU between frames 83 and 93 (for Model A300 series airplanes) or between frames 85 and 93 (for Model A310 and A300-600 series airplanes), as applicable; and measure the material thickness of the flanges; in accordance with Airbus Service Bulletin A300-36-0033 (for Model A300 series airplanes), A300-36-6024 (for Model A300-600 series airplanes), or A310-36-2032 (for Model A310 series airplanes), all dated October 17, 1994; as applicable. If any defect is found, prior to further flight, repair the defect in accordance with the applicable service bulletin.

(1) If the material thickness of the flanges is within the limits [Area 1: greater than or equal to 0.56 mm (0.022 inch); Area 2: greater than or equal to 0.48 mm (0.019 inch)] specified in Airbus Service Bulletin A300-36-0033 (for Model A300 series airplanes), A300-36-6024 (for Model A300-600 series airplanes), or A310-36-2032 (for Model A310 series airplanes), all dated October 17, 1994; as applicable: Prior to further flight, perform an inspection using a magnifying glass or appropriate gauge to detect cracks of the inner and outer surfaces of the flanges, in accordance with the applicable service bulletin.

(i) If no crack is found, and the material thickness of all flanges is within the limits [Area 1: greater than or equal to 0.9 mm (0.035 inch)] specified in the applicable service bulletin: No further action is required by this AD.

(ii) If no crack is found, and the material thickness of any flange is outside the limits [Area 1: less than 0.9 mm (0.035 inch)] specified in the applicable service bulletin: Repeat the inspection required by paragraph (a) of this AD at the time specified in the applicable service bulletin.

(iii) If any crack is found: Prior to further flight, accomplish either paragraph (a)(1)(iii)(A) or (a)(1)(iii)(B) of this AD.

(A) Replace the duct with a new or serviceable duct in accordance with the applicable service bulletin. Or

(B) Operate the airplane with the bleed air system of the APU inoperative, in accordance with the provisions and limitations specified in the operator's FAA-approved Master Minimum Equipment List (MMEL).

(2) If the material thickness of any flange is outside the limits [Area 1: less than 0.56 mm (0.022 inch); Area 2: less than 0.48 mm (0.019 inch)] specified in Airbus Service Bulletin A300-36-0033 (for Model A300 series airplanes), A300-36-6024 (for Model A300-600 series airplanes), and A310-36-2032 (for Model A310 series airplanes), all dated October 17, 1994; as applicable: Prior to further flight, accomplish either paragraph (a)(1)(iii)(A) or (a)(1)(iii)(B) of this AD.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 ofthe 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) The actions shall be done in accordance with All Operator Telex (AOT) 36-02, dated August 23, 1995; Airbus Service Bulletin A300-36-0033, dated October 17, 1994; Airbus Service Bulletin A300-36-6024, dated October 17, 1994; and Airbus Service Bulletin A310-36-2032, dated October 17, 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 Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in French airworthiness directive 95-182-184(B), dated September 27, 1995.

(e) This amendment becomes effective on April 17, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Airbus Model A300, A310, and A300-600 series airplanes was published in the Federal Register on January 8, 1998 (63 FR 1070). That action proposed to require inspections to detect defects of the flanges of the bleed air ducts of the auxiliary power unit (APU), and to measure the material thickness of the flanges; and repair, replacement of the duct with a new or serviceable duct, or operation of the airplane with the bleed air system of the APU inoperative, if necessary. For certain airplanes, the action also proposed to require an inspection to detect cracks of the flanges, and follow-on actions.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the costto the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 84 airplanes of U.S. registry will be affected by this AD, that it will take approximately 9 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $45,360, or $540 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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 levelsof 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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 the following new airworthiness directive: