Airworthiness Directives; Airbus Model A320 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-08-AD]

RIN 2120-AA64

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 all Airbus Model A320 series

airplanes. This proposal would require repetitive inspections to detect

fatigue cracking in certain areas of the fuselage; and corrective

action, if necessary. This proposal also would provide for an optional

terminating action for the repetitive inspections. 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 fatigue cracking of

the fuselage, which could result in reduced structural integrity of the

airplane.

DATES: Comments must be received by May 14, 1998.

[[Page 18165]]

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 98-NM-08-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-08-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-08-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 all Airbus Model A320 series airplanes. The DGAC

advises that, during full-scale fatigue testing, cracking was detected

at flight cycles varying from 76,000 to 111,664 in several areas of the

fuselage:

On the bottom panel of the keel beam at the frame 46,

stringer 37 intersection at the pressure bulkhead;

On the outboard flanges of frames 38 through 41, between

stringers 12 and 21, originating at the fastener holes; and

On the upper rivet row on the outer skin panel of the

longitudinal lap joint, between frames 53 and 54, in the area of

stringer 6; and between frames 48 and 64.

Such fatigue cracking, if not detected and corrected in a timely

manner, could result in reduced structural integrity of the airplane.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A320-53-1034, dated March 30,

1992, which describes procedures for repetitive ultrasonic inspections

to detect cracking in the bottom panels of the keel beam (both left and

right), in the area of the frame 46 and stringer 37 intersection at the

pressure bulkhead; and repair, if necessary.

Airbus also has issued Service Bulletin A320-53-1033, Revision 3,

dated July 4, 1994, which describes procedures for modification of six

specific fastener holes in the area of the frame 46 and stringer 37

intersection. This modification involves removing existing fasteners;

cleaning the fastener holes; performing an eddy current inspection of

the fastener holes to detect cracking, and repairing cracking if

necessary; cold expanding the crack-free fastener holes; and installing

oversize fasteners. Accomplishment of this modification would eliminate

the need for the repetitive inspections specified in Airbus Service

Bulletin A320-53-1034.

Airbus also has issued Service Bulletin A320-53-1032, Revision 1,

dated January 15, 1998, which describes procedures for repetitive

visual inspections to detect cracking on the outboard flanges around

the fastener holes of frames 38 to 41, between stringers 12 and 21; and

repair, if necessary.

Airbus also has issued Service Bulletin A320-53-1031, dated

December 9, 1994, which describes procedures for modification of frames

38 to 41, between stringers 12 and 21. This modification involves cold

expanding fastener holes and replacing the existing fasteners with new

fasteners. Accomplishment of this modification, if performed prior to

the accumulation of 20,000 total flight cycles, would eliminate the

need for the repetitive inspections specified in Airbus Service

Bulletin A320-53-1032.

Airbus also has issued Service Bulletin A320-53-1057, Revision 2,

dated July 5, 1996, which describes procedures for repetitive visual or

eddy current inspections to detect cracking in the upper rivet row of

the outer skin panel of the longitudinal lap joints in four specific

areas; and repair, if necessary. The following areas are to be

inspected:

Between frames 48 and 64, next to stringer 6, on the left-

and right-hand sides of the fuselage;

Between frames 60 and 64, next to stringer 32, on the

left-hand side of the fuselage;

Between frames 59 and 64, next to stringer 32, on the

right-hand side of the fuselage; and

Between frames 58 and 64, next to stringer 41, on the

right-hand side of the fuselage.

Airbus also has issued Service Bulletin A320-53-1056, Revision 02,

dated February 16, 1998, which describes procedures for modification of

the outer skin panel of the longitudinal lap joints in multiple areas

of the rear fuselage. This modification involves measuring the

protrusion of existing rivets in the upper rivet rows of the

longitudinal lap joints; and replacing existing rivets with repair

rivets, if necessary. Accomplishment of this modification, if performed

prior to the accumulation of 20,000 total flight cycles, would

eliminate the need for the repetitive inspections specified in Airbus

Service Bulletin A320-53-1057.

Accomplishment of the modifications specified in Airbus Service

Bulletins A320-53-1033, A320-53-1031, and A320-53-1056 is intended to

adequately address the identified unsafe condition.

The DGAC classified Airbus Service Bulletins A320-53-1034, A320-53-

1032, and A320-53-1057 as mandatory and issued French airworthiness

directives 97-314-108(B), 97-313-107(B), and 97-312-106(B), all dated

October 22, 1997, in order to assure the

[[Page 18166]]

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 require accomplishment of

the actions specified in Airbus Service Bulletins A320-53-1034, A320-

53-1032, and A320-53-1057, described previously, except as discussed in

the paragraphs that explain differences between this proposed rule and

the service bulletins (below). In addition, this proposed AD would

provide for optional terminating action for the repetitive inspections.

Operators should note that, in consonance with the findings of the

DGAC, the FAA has determined that the repetitive inspections proposed

by this AD can be allowed to continue in lieu of accomplishment of a

terminating action. In making this determination, the FAA considers

that, in this case, long-term continued operational safety will be

adequately assured by accomplishing the repetitive inspections to

detect cracking before it represents a hazard to the airplane.

Differences Between Proposed Rule and Service Bulletins

Operators should note that, unlike the procedures described in

Airbus Service Bulletins A320-53-1034, A320-53-1032, and A320-53-1057,

this proposed AD would not permit further flight if cracking is

detected in any section of the fuselage. The FAA has determined that,

because of the safety implications and consequences associated with

such cracking, any portion of the fuselage that is found to be cracked

must be repaired or modified prior to further flight, in accordance

with the applicable service bulletin, except as discussed in the next

paragraph.

Operators also should note that, although Airbus Service Bulletins

A320-53-1034, A320-53-1033, and A320-53-1032 specify that the

manufacturer may be contacted for disposition of certain repair

conditions, this proposed AD would require the repair of those

conditions to be accomplished in accordance with a method approved by

the FAA.

Cost Impact

The FAA estimates that 118 airplanes of U.S. registry would be

affected by this proposed AD.

It would take approximately 6 work hours per airplane to accomplish

the proposed ultrasonic inspection, at an average labor rate of $60 per

work hour. Based on these figures, the cost impact of the ultrasonic

inspection proposed by this AD on U.S. operators is estimated to be

$42,480, or $360 per airplane, per inspection cycle.

It would take approximately 19 work hours per airplane to

accomplish the proposed visual inspection on the outboard flanges, at

an average labor rate of $60 per work hour. Based on these figures, the

cost impact of the visual inspection proposed by this AD on U.S.

operators is estimated to be $134,520, or $1,140 per airplane, per

inspection cycle.

It would take approximately 15 work hours per airplane to

accomplish either the visual or eddy current inspection of the

longitudinal lap joints, at an average labor rate of $60 per work hour.

Based on these figures, the cost impact of these inspections proposed

by this AD on U.S. operators is estimated to be $106,200, or $900 per

airplane, per inspection cycle.

The cost impact figures discussed above are 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.

Should an operator elect to accomplish the optional terminating

action specified in Airbus Service Bulletin A320-53-1033 that would be

provided by this AD action, it would take approximately 5 work hours to

accomplish it, at an average labor rate of $60 per work hour. The cost

of required parts would be approximately $72 per airplane. Based on

these figures, the cost impact of that optional terminating action

would be $372 per airplane.

Should an operator elect to accomplish the optional terminating

action specified in Airbus Service Bulletin A320-53-1031 that would be

provided by this AD action, it would take approximately 1 work hour

(excluding access and closeup) per fastener hole to accomplish it, at

an average labor rate of $60 per work hour. The cost of required parts

would be approximately $4,047 (for one modification kit). Based on

these figures, the cost impact of that optional terminating action

would be a minimum of $4,107 per airplane.

Should an operator elect to accomplish the optional terminating

action specified in Airbus Service Bulletin A320-53-1056 that would be

provided by this AD action, it would take approximately 258 work hours

to accomplish it, at an average labor rate of $60 per work hour. The

cost of required parts would be approximately $420 per airplane. Based

on these figures, the cost impact of that optional terminating action

would be $15,900 per airplane.

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:

[[Page 18167]]

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 Industrie: Docket 98-NM-08-AD.

Applicability: All Model A320 series airplanes, certificated in

any category.

Note 1: This AD applies to each airplane identified in the

preceding applicability provision, regardless of whether it has been

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 (h) 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 fatigue cracking of the fuselage, which

could result in reduced structural integrity of the airplane,

accomplish the following:

(a) For airplanes on which Airbus Modification 21202 (reference

Airbus Service Bulletin A320-53-1033, Revision 3, dated July 4,

1994) has not been accomplished: Prior to the accumulation of 30,000

total flight cycles, or within 6 months after the effective date of

this AD, whichever occurs later, perform an ultrasonic inspection to

detect cracking in the bottom panels of the keel beam (both left and

right), in the area of the frame 46 and stringer 37 intersection at

the pressure bulkhead, in accordance with Airbus Service Bulletin

A320-53-1034, dated March 30, 1992. Thereafter, repeat the

ultrasonic inspection at intervals not to exceed 6,000 flight

cycles. If any crack is found, prior to further flight, repair in

accordance with the service bulletin, except as provided by

paragraph (g) of this AD.

(b) Accomplishment of Airbus Modification 21202 in accordance

with Airbus Service Bulletin A320-53-1033, Revision 3, dated July 4,

1994, constitutes terminating action for the repetitive inspection

requirement of paragraph (a) of this AD.

(c) For airplanes on which Airbus Modification 21346 (reference

Airbus Service Bulletin A320-53-1031, dated December 9, 1994) has

not been accomplished prior to the accumulation of 20,000 total

flight cycles: Prior to the accumulation of 30,000 total flight

cycles, or within 6 months after the effective date of this AD,

whichever occurs later, perform a visual inspection to detect

cracking on the outboard flanges around the fastener holes of frames

38 to 41, between stringers 12 and 21, in accordance with Airbus

Service Bulletin A320-53-1032, Revision 1, dated January 15, 1998.

Thereafter, repeat the visual inspection at intervals not to exceed

6,000 flight cycles. If any crack is found, prior to further flight,

repair in accordance with the service bulletin, except as provided

by paragraph (g) of this AD. Accomplishment of a repair in

accordance with the service bulletin terminates the repetitive

inspection requirements for the area repaired.

(d) Accomplishment of Airbus Modification 21346 in accordance

with Airbus Service Bulletin A320-53-1031, dated December 9, 1994,

prior to the accumulation of 20,000 total flight cycles constitutes

terminating action for the repetitive inspection requirement of

paragraph (c) of this AD.

(e) For airplanes on which Airbus Modification 21905 (reference

Airbus Service Bulletin A320-53-1056, Revision 02, dated February

16, 1998) has not been accomplished: Prior to the accumulation of

20,000 total flight cycles, or within 6 months after the effective

date of this AD, whichever occurs later, perform a visual or eddy

current inspection to detect cracking in the upper rivet row of the

longitudinal lap joint, in accordance with Airbus Service Bulletin

A320-53-1057, Revision 2, dated July 5, 1996.

(1) Thereafter, repeat the inspection at one of the following

intervals:

(i) If the immediately preceding inspection was conducted using

visual techniques, conduct the next inspection within 4,000 flight

cycles.

(ii) If the immediately preceding inspection was conducted using

eddy current techniques, conduct the next inspection within 12,000

flight cycles.

(2) If any crack is found, prior to further flight, repair in

accordance with the service bulletin, except as provided by

paragraph (g) of this AD. Accomplishment of a repair in accordance

with the service bulletin terminates the repetitive inspection

requirements for the area repaired.

(f) Accomplishment of Airbus Modification 21905 in accordance

with Airbus Service Bulletin A320-53-1056, Revision 02, dated

February 16, 1998, prior to the accumulation of 20,000 total flight

cycles constitutes terminating action for the repetitive inspection

requirements specified in paragraph (e)(1) of this AD.

(g) If any crack is found during any inspection required by

paragraph (a), (c), or (e) 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.

(h) 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.

(i) 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 directives 97-314-108(B), 97-313-107(B), and 97-312-

106(B), all dated October 22, 1997.

Issued in Renton, Washington, on April 7, 1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 98-9753 Filed 4-13-98; 8:45 am]

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