Airworthiness Directives; Airbus Model A320 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-141-AD]

Airworthiness Directives; Airbus Model A320 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to certain Airbus Model A320 series

airplanes. This proposal would require replacement of the check valves

of the thrust reverser with modified valves on certain airplane

configurations and the replacement of the manual control valves of the

thrust reverser with modified valves on certain other airplane

configurations. This proposal is prompted by recent engineering

analysis, which revealed that if the non-return valve installed on the

hydraulic return line of the thrust reverser were to jam in the closed

position, it could cause pressurization of the Hydraulic Control Unit

(HCU). The actions specified by the proposed AD are intended to prevent

possible pressurization of the HCU, due to jamming of the non-return

valve in the hydraulic return line, and consequent deployment of a

thrust reverser during flight, which could affect the controllability

of the airplane.

DATES: Comments must be received by December 27, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-141-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056. Comments may be inspected at this

location between 9:00 a.m. and 3:00 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: Stephen Slotte, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2797; fax (206) 227-1320.

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 94-NM-141-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. 94-NM-141-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion -

The Direction Generale de l'Aviation Civile (DGAC), which is the

airworthiness authority for France, recently notified the FAA that an

unsafe condition may exist on certain Airbus A320 series airplanes. The

DGAC advises that recent engineering analysis has revealed that, if the

non-return valve installed on the thrust reverser hydraulic return line

on a Model A320 series airplane were to jam in the closed position for

any reason, it could cause pressurization of the Hydraulic Control Unit

(HCU). Pressurization of the HCU, if not corrected, could result in the

deployment of a thrust reverser during flight, which could affect the

controllability of the airplane. (There have been no incidents of the

non-return valve jamming on in-service airplanes, however.) -

Airbus has issued Service Bulletin A320-29-1048, Revision 1, dated

December 4, 1992, which describes procedures for replacing the Engine 1

and Engine 2 thrust reverser check valves with modified valves on

airplanes equipped with CFM series engines, and replacing the Engine 1

and Engine 2 thrust reverser manual control valves with modified valves

on airplanes equipped with International Aero Engines (IAE) engines.

Replacement in accordance with the service bulletin of these valves

with a modified check or manual control valve on the thrust reverser

line will allow for leakage and prevent pressurization of the HCU. The

DGAC has classified this service bulletin as mandatory and issued

French Airworthiness Directive 94-059-054(B), dated March 16, 1994, in

order to assure the continued airworthiness of these airplanes in

France. -

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. -

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 require replacing the

thrust reverser check valves with modified valves on Engine 1 and

Engine 2 of airplanes equipped with CFM series engines. It would also

require replacing the thrust reverser manual control valves with

modified valves on the Engine 1 and Engine 2 of airplanes equipped with

IAE engines. The actions would be required to be accomplished in

accordance with the service bulletin described previously. -

The FAA estimates that 53 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 3 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $60 per work hour. Required parts would be

provided by the manufacturer at no cost to the operators. Based on

these figures, the total cost impact of the proposed AD on U.S.

operators is estimated to be $9,540, or $180 per airplane. -

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the proposed

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

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. -

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. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended] -

2. Section 39.13 is amended by adding the following new

airworthiness directive:

Airbus Industrie: Docket 94-NM-141-AD.

-Applicability: Model A320 series airplanes as specified in

Airbus Industrie Service Bulletin A320-29-1048, Revision 1, dated

December 4, 1992, certificated in any category. -

Compliance: Required as indicated, unless accomplished

previously. -

To prevent deployment of a thrust reverser during flight, and

consequently affecting the controllability of the airplane,

accomplish the following: -

(a) Within 5 months after the effective date of the AD,

accomplish paragraph (a)(1) or (a)(2) of this AD, as applicable, in

accordance with Airbus Industrie Service Bulletin A320-29-1048,

Revision 1, dated December 4, 1992. -

(1) For airplanes equipped with CFM series engines: Replace the

Engine 1 and Engine 2 check valves of the thrust reverser in the

nacelle with modified valves as specified in the service bulletin. -

(2) For airplanes equipped with International Aero Engines

(IAE): Replace the Engine 1 and Engine 2 manual control valves of

the thrust reverser on the pylon with modified valves as specified

in the service bullein. -

(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, 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: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

-(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.

Issued in Renton, Washington, on November 7, 1994.

S.R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-27968 Filed 11-10-94; 8:45 am]

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