Airworthiness Directives; Airbus Model A310 and A300-600 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-17-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A310 and A300-600 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 A310 and

A300-600 series airplanes. This proposal would require repetitive

visual inspections to detect corrosion on the lower rim area of the

fuselage rear pressure bulkhead; and follow-on actions, if necessary.

This proposal is prompted by issuance of mandatory continuing

airworthiness information by a foreign civil airworthiness authority.

The actions specified by the proposed AD are intended to detect and

correct corrosion at the lower rim area of the fuselage rear pressure

bulkhead, which could result in reduced structural integrity of the

bulkhead, and consequent decompression of the cabin.

DATES: Comments must be received by April 20, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 98-NM-17-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: Norman B. Martenson, Manager,

International Branch, ANM-116, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)

227-2110; fax (425) 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 98-NM-17-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-114, Attention: Rules

Docket No. 98-NM-17-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, notified the FAA that an unsafe

condition may exist on certain Airbus Model A310 and A300-600 series

airplanes. The DGAC advises that, during routine maintenance, severe

[[Page 13573]]

corrosion was found in the lower rim area of the aft pressure bulkhead

between stringer 27, on the left- and right-hand sides of the airplane.

The corrosion was found in two separate areas: on the inner rim angle

of the bulkhead in the area of the drainhole, and in the cleat profile

splice at the airplane centerline. The corrosion on the inner rim angle

of the bulkhead has been attributed to damage of the surface protection

when cleaning the drainholes or during the modifications specified in

Airbus Service Bulletin A310-53-2025 or A300-53-6006. The corrosion of

the cleat profile splice has been attributed to clogged drainholes or

incomplete adhesion of sealant during accomplishment of the

modifications specified in the service bulletins. Such corrosion, if

not detected and corrected in a timely manner, could result in reduced

structural integrity of the bulkhead, and consequent decompression of

the cabin.

Explanation of Relevant Service Information

The manufacturer has issued Airbus Service Bulletins A310-53-2092

(for Model A310 series airplanes) and A300-53-6066 (for Model A300-600

series airplanes), both dated October 16, 1996. These service bulletins

describe procedures for repetitive visual inspections to detect

corrosion on the lower rim area of the fuselage rear pressure bulkhead;

and follow-on corrective actions (which include removal of corrosion

and repair), if necessary. The DGAC classified these service bulletins

as mandatory and issued French airworthiness directive 97-061-212(B),

dated February 26, 1997, in order to assure the continued airworthiness

of these airplanes in France.

FAA's Conclusions

These airplane models are manufactured in France and are 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 require accomplishment of

the actions specified in the service bulletins described previously,

except as discussed below.

Differences Between Proposed Rule and Service Bulletins

Operators should note that, unlike the procedures previously

described in Airbus Service Bulletins A310-53-2092 (for Model A310

series airplanes) and A300-53-6066 (for Model A300-600 series

airplanes), both dated October 16, 1996, this proposed AD would not

permit further flight if corrosion is detected. The FAA has determined

that, because of the safety implications and consequences associated

with such corrosion, any subject part of the fuselage and aft pressure

bulkhead that is found to have corrosion must be repaired prior to

further flight.

Cost Impact

The FAA estimates that 90 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 62 work

hours per airplane to accomplish the proposed 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

$334,800, or $3,720 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 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

AIRBUS: Docket 98-NM-17-AD.

Applicability: Model A310 and A300-600 series airplanes on which

Airbus Modification 6788 has not 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 (c) 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 detect and correct corrosion at the lower rim area of the

fuselage rear pressure bulkhead, which could result in reduced

structural integrity of the bulkhead, and consequent decompression

of the cabin, accomplish the following:

(a) Within 18 months after the effective date of this AD: Except

as provided by paragraph (b) of this AD, perform a visual inspection

to detect corrosion of the lower rim area of the aft pressure

bulkhead, in accordance with Airbus Service Bulletin A310-53-2092

(for Model A310 series

[[Page 13574]]

airplanes) or Airbus Service Bulletin A300-53-6066 (for Model A300-

600 series airplanes), both dated October 16, 1996, as applicable.

If any discrepancy is found, prior to further flight, repair in

accordance with the applicable service bulletin. Thereafter, repeat

the inspection at the interval specified in paragraph (a)(1) or

(a)(2), as applicable.

(1) For airplanes on which Airbus Service Bulletin A310-53-2036

or A300-53-6017 has not been accomplished: Repeat the inspection at

intervals not to exceed 3 years.

(2) For airplanes on which Airbus Service Bulletin A310-53-2036

or A300-53-6017 has been accomplished: Repeat the inspection at

intervals not to exceed 5 years.

(b) If any discrepancy is found during an inspection required by

paragraph (a) of this AD, and the applicable service bulletin

specifies to contact Airbus for appropriate action: Prior to further

flight, repair in accordance with a method approved by the Manager,

International Branch, ANM-116, FAA, Transport Airplane Directorate.

(c) 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.

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.

(d) 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.

Note 3: The subject of this AD is addressed in French

airworthiness directive 97-061-212(B), dated February 26, 1997.

Issued in Renton, Washington, on March 13, 1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 98-7223 Filed 3-19-98; 8:45 am]

BILLING CODE 4910-13-U