Airworthiness Directives; Airbus Model A300-600 and A310 Series Airplanes Equipped With General Electric Model CF6-80 Engines

DEPARTMENT OF AGRICULTURE

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 95-NM-175-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A300-600 and A310 Series

Airplanes Equipped With General Electric Model CF6-80 Engines

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 A300-600 and

A310 series airplanes. This proposal would require an inspection to

detect defects of the directional pilot valves (DPV); and replacement

of any defective DPV with a new DPV, or deactivation of the thrust

reverser system, if necessary. This proposal is prompted by a report

indicating that, during a maintenance check, an uncommanded deployment

and stowage of the thrust reverser occurred due to improperly modified

DPV's. The actions specified by the proposed AD are intended to prevent

uncommanded deployment and stowage of the thrust reverser during

maintenance activities, as a result of improperly modified DPV's, which

could result in injury to maintenance personnel or other people on the

ground.

DATES: Comments must be received by June 10, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 95-NM-175-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: Charles Huber, Aerospace Engineer,

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

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 95-NM-175-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. 95-NM-175-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 Model A300-600 and A310

series airplanes, equipped with General Electric Model CF6-80 engines.

The DGAC advises that it has received a report indicating that, during

a maintenance check, an uncommanded deployment and stowage of the

thrust reverser occurred.

Investigation of this incident revealed that, when the thrust

reverser handle was moved from the ``stow'' position to the thrust

reverser test point, the directional pilot valve (DPV) stuck in the

``open'' (``deploy'') position. The air supply first caused the thrust

reverser to deploy, and then caused the DPV solenoid to move the DPV to

the ``stow'' direction, which resulted in the thrust reverser stowing.

This same sequence of events happened when the opposite engine was

tested. When both DPV's were replaced and a functional test carried

out, no anomaly was found. This indicated that the originally-installed

DPV's apparently were faulty.

Further tests carried out at the Airbus flight line on a General

Electric CF6-80C2 engine with the faulty DPV's installed, demonstrated

that deployment of the thrust reverser could not be reproduced with the

engine running. The thrust reverser deployment could be recreated only

with a progressive increase of ground air supply at low pressure

(approximately 10 to 15 psi) to the ground test point on the airplane.

When direct test pressure of 28 psi was applied to the DPV, the valve

reseated to the ``stow'' position. (This same scenario was confirmed by

bench testing performed by both General Electric and Allied Signal.)

Further investigation of the two faulty DPV's revealed that the

valves had been improperly modified when procedures specified in

General Electric Service Bulletin 78-031 had been accomplished on the

engine. The DPV armature spring had not been replaced with a new

stronger spring in accordance with the service bulletin instructions.

Accordingly, such an improperly modified DPV, if not corrected,

could result in uncommanded deployment and stowage of the thrust

reverser during maintenance activities, which consequently could cause

injury to maintenance personnel or other people on the ground.

[[Page 18700]]

Explanation of Relevant Service Information

Airbus has issued All Operators Telex (AOT) 78-05, Revision 01,

dated February 8, 1995, which describes procedures for a one-time

inspection to detect defects of the DPV; and replacement of the

defective DPV with a new DPV, or deactivation of the thrust reverser

system, if necessary. The DGAC classified this AOT as mandatory and

issued French airworthiness directive 95-052-176(B), dated March 15,

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 the Requirements of the Proposed Rule

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design, the

proposed AD would require a one-time inspection to detect defects of

the DPV. If a defective DPV is detected, it would be required to be

replaced with a new DPV, or thrust reverser system would be required to

be deactivated until the DPV is replaced. The inspection and

replacement actions would be required to be accomplished in accordance

with the AOT described previously.

Cost Impact

The FAA estimates that 43 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 10 work

hours per airplane to accomplish the proposed one-time inspection, and

that the average labor rate is $60 per work hour. Based on these

figures, the cost impact of the proposed AD on U.S. operators is

estimated to be $25,800, or $600 per airplane.

The 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.

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.

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 USC 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

Airbus Industrie: Docket 95-NM-175-AD.

Applicability: Model A300B4-601, -603, -605R, A300-F4-605R, and

A310-203, -203C, -204, -304, -308 series airplanes, equipped with

General Electric Model CF6-80 engines; on which General Electric

Service Bulletin 78-031 has been accomplished; 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 uncommanded deployment and stowage of the thrust

reverser during maintenance activities, accomplish the following:

(a) Within 600 flight hours after the effective date of this AD,

perform an inspection to detect defects of the directional pilot

valves (DPV) in accordance with Airbus All Operators Telex (AOT) 78-

05, Revision 01, February 8, 1995.

(1) If no defects are detected, no further action is required by

this AD.

(2) If any defect is detected, prior to further flight, either

replace the defective DPV with a new DPV in accordance with the AOT;

or deactivate the thrust reverser system in accordance with approved

procedures of the Minimum Equipment List (MEL) until the DPV is

replaced

(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 2: 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 April 23, 1996.

S. R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 96-10509 Filed 4-26-96; 8:45 am]

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