AD 96-23102

[Federal Register Volume 61, Number 177 (Wednesday, September 11, 1996)] [Proposed Rules] [Pages 47829-47831] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 96-23102]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-164-AD] RIN 2120-AA64

Airworthiness Directives; Airbus Industrie Model A320 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, that currently requires repetitive visual inspections and end-float checks of the ram air turbine (RAT), and replacement of the RAT, if necessary. This new action would require installation of a modified RAT, which would constitute terminating action for the currently required inspections. This proposal is prompted by the development of a modification of the RAT that positively addresses the unsafe condition. The actions specified by the proposed AD are intended to prevent the RAT from breaking away from it support leg, which could damage the airplane structure and systems, and could injure ground personnel.

DATES: Comments must be received by October 21, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-164-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. FOR FURTHER INFORMATION CONTACT: Chuck Huber, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

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1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2589; fax (206) 227-1149. SUPPLEMENTARY INFORMATION: Comments Invited Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 96-NM-164-AD.'' The postcard will be date stamped and returned to the commenter. Availability of NPRMs Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-164-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On January 4, 1994, the FAA issued AD 94-01-11, amendment 39-8793 (59 FR 5462, February 1, 1994), applicable to Airbus Model A320 series airplanes equipped with certain ram air turbines (RAT). That AD requires repetitive detailed visual inspections and end-float checks of the RAT to detect various discrepancies, and replacement of the RAT with a new RAT, if necessary. That action was prompted by at least two reports indicating that, during on-ground functional testing of the RAT installed on these airplanes, the RAT propeller assembly separated from the support leg. In one case, the turbine was fully detached from the leg and traveled 4 meters forwards. In the other case, the turbine had moved 18 mm from the leg, but was not detached. Investigation of these failures revealed that the detachment was due to the failure of the ball bearings associated with the propeller assembly; the ball bearings failed as a result of excessive overloading and overtemperature. The requirements of AD 94-01-11 are intended to prevent the RAT from breaking away from its support leg, which could damage the airplane structure and systems, and could injure ground personnel.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the Direction Generale de l'Aviation Civile (DGAC), which the airworthiness authority for France, has advised the FAA that manufacturer has developed a modified RAT assembly that positively addresses the previous problems experienced with the RAT on the Airbus Model A320 series airplanes.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A320-29-1065, dated February 28, 1995, which describes procedures for installing a new modified RAT, identified as Modification 24701. The modified RAT includes an improved ball bearing that is not susceptible to the overloading and overtemperature problems experienced previously. The DGAC classified this service bulletin as mandatory and issued French airworthiness directive (CN) 93-057-041(B)R1, dated June 7, 1995, in order to assure the continued airworthiness of these airplanes in France.

FAA's Conclusions

This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would supersede AD 94-01-11. It would continue to require repetitive visual inspections and end-float checks of the RAT, and replacement of the RAT, if necessary. It also would require the installation of the new modified RAT (Modification 24701) as terminating action for the repetitive inspections. The modification would be required to be accomplished in accordance with the service bulletin described previously. This proposed action also would limit the applicability of the AD to only airplanes on which Modification 24701 has not been installed. This modification was installed prior to delivery on airplanes having manufacturer's serial number (MSN) 455, 471, 531, and subsequent.

Cost Impact

There are approximately 94 Airbus Model A320 series airplanes of U.S. registry that would be affected by this proposed AD. The inspections/checks that are currently required by AD 94-01-11 take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the current inspection/check requirement is estimated to be $5,640, or $60 per airplane, per inspection/check. The terminating modification that is proposed in this AD action would take approximately 74 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact on U.S. operators of the proposed modification requirement of this AD is estimated to be $417,360, or $4,440 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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For the reasons discussed above, I certify that this proposed regulation (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); and (3) if promulgated, 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 draft regulatory 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, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-8793 (59 FR 4562, February 1, 1994), and by adding a new airworthiness directive (AD), to read as follows:

Airbus Industrie: Docket 96-NM-164-AD. Supersedes AD 94-01-11, amendment 39-8793.

Applicability: Model A320-111, -211, -212, -214, -231, and -232 series airplanes; on which Airbus Industrie Modification 24701 (as described in Airbus Service Bulletin A320-29-1065, dated February 28, 1995) has not been installed; 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 (e) 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 the RAT from breaking away from its support leg, which could damage the airplane structure and systems, and could injure ground personnel, accomplish the following: (a) Perform a detailed visual inspection and an end-float check of the RAT between turbine and leg, in accordance with Airbus Industrie Service Bulletin A320-29-1061, dated April 13, 1993, at the earliest of the times specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD: (1) Within the next 450 flight hours after March 3, 1994 (the effective date of AD 94-01-11, amendment 39-8793); or (2) Before and after the first functional ground check of the RAT that is performed after March 3, 1994; or (3) After the first in-flight deployment of the RAT that occurs after March 3, 1994. (b) If no discrepancy is detected, repeat the detailed visual inspection and the end-float check after each functional ground check of the RAT, and after each in-flight deployment of the RAT.

Note 2: Airbus Industrie Service Bulletin A320-29-1061, dated April 13, 1993, references Dowty Aerospace Service Bulletin 600-29- 171, dated January 4, 1993, which provides specific descriptions of the discrepancies in paragraph 2 of that service bulletin. Note 3: The discrepancies that are addressed in this AD can only occur during use of the RAT, and not during stowage of the RAT; therefore, it is not necessary to perform the repetitive inspections and end-float checks before each functional ground check of the RAT if the RAT has not been used since the preceding inspection.

(c) If any discrepancy is detected as a result of any detailed visual inspection required by this AD, prior to further flight, accomplish the requirements of either paragraph (c)(1) or (c)(2) of this AD. (1) Replace the RAT in accordance with Airbus Industrie Service Bulletin A320-29-1061, dated April 13, 1993; and after replacement, repeat the detailed visual inspection and the end-float check required by paragraph (a) of this AD. Thereafter, repeat the detailed visual inspection and the end-float check after each functional ground check of the RAT, and after each in-flight deployment of the RAT. Or (2) Install a new modified RAT (Modification 24701) in accordance with Airbus Service Bulletin A320-29-1065, dated February 28, 1995. Installation of this modification constitutes terminating action for the repetitive visual inspections and end-float checks required by this AD. (d) Within 2 years after the effective date of this AD, install a new modified RAT (Modification 24701) in accordance with Airbus Service Bulletin A320-29-1065, dated February 28, 1995. Installation of this modification constitutes terminating action for the repetitive visual inspections and end-float checks required by this AD. (e) 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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.

Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(f) 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.

Issued in Renton, Washington, on September 4, 1996. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-23102 Filed 9-10-96; 8:45 am] BILLING CODE 4910-13-U