Airworthiness Directives; Airbus Model A319, A320, and A321 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-29-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A319, A320, and A321

Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of

comment period.

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SUMMARY: This document revises an earlier proposed airworthiness

directive (AD), applicable to certain Airbus Model A320 series

airplanes, that would have required repetitive inspections to detect

wear of the inboard flap trunnions; modification or replacement, if

necessary; and eventual modification of the trunnions, which would

terminate the repetitive inspections. That proposal was prompted by

reports of wear damage found on the inboard flap drive trunnions that

was caused by chafing of the Teflon rollers of the chain that actuates

the sliding panel of the fairing. This new action revises the proposed

AD by adding new repetitive inspections to detect wear or debonding of

the protective half-shells, and corrective actions, if necessary; and

by removing the modification requirement. This action also would expand

the applicability of the existing AD to include additional airplanes.

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

correct chafing and resultant wear damage on the inboard flap drive

trunnions or on the protective half-shells, which could result in

failure of the trunnion primary load path; this would adversely affect

the fatigue life of the secondary load path and could lead to loss of

the flap.

DATES: Comments must be received by October 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 96-NM-29-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 96-NM-29-AD.'' The postcard will be date stamped and

returned to the commenter.

Availability of Notice of Proposed Rulemaking (NPRM)

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. 96-NM-29-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14

CFR part 39) to add an airworthiness directive (AD), applicable to

certain Airbus Model A320 series airplanes, was published as an NPRM in

the Federal Register on August 30, 1996 (61 FR 45910). That NPRM would

have required repetitive inspections to detect wear of the inboard flap

trunnions; modification or replacement, if necessary; and eventual

modification of the trunnions, which would terminate the repetitive

inspections. That NPRM was prompted by reports of wear damage found on

the inboard flap drive trunnions that was caused by chafing of the

Teflon rollers of the chain that actuates the sliding panel of the

fairing. Such chafing and resultant wear damage, if not corrected,

could result in failure of the trunnion primary load path; this would

adversely affect the fatigue life of the secondary load path and could

lead to loss of the flap.

Comments Received

Due consideration has been given to the comments received in

response to the NPRM.

Requests To Delete the Proposed Modification

Several commenters request that the FAA delete the modification

requirements specified in paragraphs (a)(2), (a)(3), and (b) of the

original NPRM. These commenters state that accomplishment of Airbus

Service Bulletin A320-27-1050, Revision 3, dated October 21, 1994

(referenced in the original NPRM as the appropriate source of service

information for accomplishing the proposed modification of the inboard

flap trunnion), does not eliminate the potential for damage to the

trunnion and should not be accomplished.

The FAA concurs with the commenters' requests to delete the

modification requirement specified in the original NPRM. Since issuance

of that NPRM, the Direction Generale de l'Aviation Civile (DGAC), which

is the airworthiness authority for France,

[[Page 49310]]

advised the FAA that it has received reports of protective half-shells

detaching from the inboard flap trunnions, and other reports of wear

marks being detected on the protective half-shells on certain A320

series airplanes. These airplanes had been modified in accordance with

Airbus Service Bulletin A320-27-1050, Revision 3.

The DGAC further advises the FAA that it also has received reports

that the Teflon rollers of the chain that actuates the sliding panel of

the fairing have been found displaced and could consequently chafe the

unprotected part of the trunnion. In addition, reports indicate that

debonding of the protective half-shells was most likely caused by

incompatibility between the cleaning solution and the bonding agent.

In light of these findings, the FAA has determined that

accomplishment of the modification specified in the original NPRM does

not adequately protect the inboard flap trunnion. Therefore, the FAA

has deleted the proposed modification requirement from this

supplemental NPRM.

Request To Cite New Service Information

Several commenters advise that Airbus has issued Service Bulletin

A320-27-1108, Revision 01, dated July 15, 1997 (for Airbus Model A319,

A320, and A321 series airplanes on which protective half-shells have

been installed). The service bulletin describes procedures for

repetitive detailed visual inspections of the trunnions with the

protective half-shells. These commenters point out that protective

half-shells were installed on certain Airbus Model A319 and A321 series

airplanes during production or in accordance with Airbus Service

Bulletin A320-27-1097. Therefore, such modified Airbus Model A319 and

A321 series airplanes are subject to the same identified unsafe

condition as the affected Airbus Model A320 series airplanes.

One of these commenters states that, for airplanes that have not

been modified in accordance with Airbus Service Bulletin A320-27-1050,

Airbus has issued Revision 3 of Service Bulletin A320-27-1066 that

deletes the reference to Airbus Service Bulletin A320-27-1050 and

includes a repair solution.

In addition, one commenter states that Airbus has issued Service

Bulletin A320-27-1097, which is applicable to Airbus Model A321 series

airplanes on which Airbus Modification 23926 has not been accomplished.

The commenter also states that Airbus Service Bulletin A320-27-1097

describes repetitive inspections of the trunnion similar to those

described in Airbus Service Bulletin A320-27-1066.

The FAA infers that the commenters are requesting that the

supplemental NPRM be revised to cite new service information and expand

the applicability of the original NPRM. The FAA concurs. Since issuance

of the original NPRM, Airbus has issued the following new service

bulletins:

1. A320-27-1066, Revision 4, dated July 15, 1997 (for Model A320

series airplanes), describes new procedures for repetitive detailed

visual inspections of areas 1 and 2 of the inboard flap trunnion to

detect wear on the trunnion; and repair or replacement of the trunnion,

if necessary. Revision 4 of the service bulletin revises the

effectivity listing of earlier revisions of the service bulletin

(Revision 1 was referenced in the original NPRM as an appropriate

source of service information). Although one commenter requests that

the FAA reference Revision 3 of Airbus Service Bulletin A320-27-1066,

the FAA has determined that it is appropriate to cite the latest

revision of that service bulletin. Therefore, the FAA has revised

paragraphs (b) and (c) of the supplemental NPRM to cite Revision 4 of

Airbus Service Bulletin A320-27-1066 as an appropriate source of

service information.

2. A320-27-1097, Revision 01, dated July 15, 1997 (for Model A321

series airplanes), describes essentially identical procedures to those

specified in Airbus Service Bulletin A320-27-1066 (discussed above) for

Airbus Model A321 series airplanes. The FAA finds that accomplishment

of these procedures will adequately detect and correct wear of the

inboard trunnion. Therefore, the FAA has revised paragraphs (b) and (c)

of the supplemental NPRM to cite Revision 01 of Airbus Service Bulletin

A320-27-1097 as an appropriate source of service information.

3. A320-27-1108, Revision 01, dated July 15, 1997 (for Model A319,

A320, and A321 series airplanes), describes procedures for repetitive

detailed visual inspections of the protective half-shell (area 1) to

detect wear or debonding, and detailed visual inspections of the

trunnion (area 2) to detect wear. In addition, this service bulletin

describes follow-on corrective actions that include further inspections

of the trunnions and/or protective half-shells; repair of the inboard

flap trunnion by installing a new protective half-shell of the drive

trunnion of the inboard flap, or replacing the existing half-shell; and

replacement of the trunnion with a new or serviceable trunnion. The FAA

has determined that accomplishment of these follow-on inspections and

corrective actions will adequately detect and correct wear of the

protective half-shells and the trunnion, and debonding of the

protective half-shells. Therefore, the FAA has revised paragraphs (a)

and (c) of the supplemental NPRM to cite Revision 01 of Airbus Service

Bulletin A320-27-1108 as an appropriate source of service information.

The DGAC classified the Airbus service bulletins as mandatory, and

issued French airworthiness directive 96-271-092(B) R1, dated October

8, 1997, in order to assure the continued airworthiness of these

airplanes in France.

In addition, because the FAA finds that Airbus Model A319 and A321

series airplanes also are subject to the identified unsafe condition of

this proposed AD, the applicability of this supplemental NPRM, and the

cost impact information, below, have been revised accordingly.

Differences Between Supplemental NPRM and Service Information

Operators should note that, although the service bulletins specify

that the manufacturer may be contacted for disposition of certain wear

conditions found on the flap trunnions, this supplemental NPRM would

require repair of the wear condition in accordance with a method

approved by the FAA, or the DGAC (or its delegated agent). In light of

the action that would be required to address the identified unsafe

condition, and in consonance with existing bilateral airworthiness

agreements, the FAA has determined that a repair approved by either the

FAA or the DGAC would be acceptable for compliance with this

supplemental NPRM.

Request To Establish an Alternative Compliance Time for Certain

Airplanes

One commenter requests that the FAA establish a grace period of 18

months for the compliance time threshold of 10,000 total flight hours

specified in paragraph (b) of the original NPRM. The commenter states

that no accomplishment period exists for airplanes that have passed the

proposed limit, and that all of its Airbus Model A320 series airplanes

have accumulated in excess of 11,000 total flight hours. Therefore,

operators would be subject to severe operational impact under the

compliance time specified by the original NPRM.

The FAA acknowledges that a grace period would have been

appropriate; however, as discussed previously, the FAA has deleted the

modification requirements specified in paragraphs (a)(2), (a)(3), and

(b) of the original NPRM.

[[Page 49311]]

Request to Change the Terminating Action in the Original NPRM

One commenter requests that the terminating action specified in

Airbus Service Bulletin A320-27-1050, Revision 3, dated October 21,

1994 [as referenced in paragraph (b) of the original NPRM] be changed

to the terminating action specified in Airbus Service Bulletin A320-27-

1117, dated September 16, 1997. The commenter states that this new

service bulletin specifies a new design for the protective clamp

assembly and sliding fairing, which incorporates a lockwire to the

protective clamp assembly and redesigns the sliding fairing to reduce

the flexibility of the assembly and reduce the clearance between the

trunnion fitting and clamp assembly. The commenter also states that the

new design eliminates the potential for damage to the unprotected

portion of the trunnion, and that the new, thicker steel wear pads on

the clamp assembly are more wear resistant than the half-shell design.

The FAA concurs partially with this request. As discussed

previously, the FAA agrees that the modification proposed in accordance

with Airbus Service Bulletin A320-27-1050 is not appropriate as a

terminating action and has deleted that requirement from this

supplemental NPRM. However, the FAA has not approved an alternative

terminating action at this time. The DGAC and the manufacturer advise

that the modification specified in Airbus Service Bulletin A320-27-1117

is being evaluated to determine whether it is an appropriate

terminating action for the repetitive inspections. The DGAC also states

that it will provide additional information when the evaluation is

completed. If such a modification is determined to be effective in

preventing the unsafe condition addressed by this supplemental NPRM,

the FAA may consider further rulemaking. However, the FAA considers

that it is inappropriate to delay issuance of the supplemental NPRM in

order to await completion of the evaluation.

Conclusion

Since these changes expand the scope of the originally proposed AD,

the FAA has determined that it is necessary to reopen the comment

period to provide additional opportunity for public comment.

Interim Action

This is considered to be interim action. The manufacturer has

advised that it currently is developing a modification that will

positively address the unsafe condition addressed by this AD. Once this

modification is developed, approved, and available, the FAA may

consider additional rulemaking.

Cost Impact

The FAA estimates that 132 airplanes of U.S. registry would be

affected by this AD, that it would take approximately 1 work hour per

airplane to accomplish any of the proposed inspections, and that the

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

cost impact of this AD on U.S. operators is estimated to be $7,920, or

$60 per airplane, per inspection cycle.

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 Industrie: Docket 96-NM-29-AD.

Applicability: All Model A319, A320, and A321 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 (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 detect and correct chafing and resultant wear damage on the

inboard flap drive trunnions or on the protective half-shells, which

could result in failure of the trunnion primary load path, adversely

affect the fatigue life of the secondary load path, and lead to loss

of the flap; accomplish the following:

(a) For airplanes on which a protective half-shell has been

installed over area 1 of the left or right inboard flap trunnion:

Perform a detailed visual inspection of the protective half-shell

(area 1) to detect wear or debonding, and perform a detailed visual

inspection of the trunnion (area 2) to detect wear at the time

specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as

applicable; in accordance with Airbus Service Bulletin A320-27-1108,

Revision 01, dated July 15, 1997.

(1) For Model A319 and Model A320 series airplanes on which

Airbus Modification 22841 has been installed: Inspect prior to the

accumulation of 2,500 flight hours after the incorporation of the

modification, or within 500 flight hours after the effective date of

this AD, whichever occurs later.

(2) For Model A321 series airplanes on which Airbus Modification

23926 has been installed, or on which the repair specified in Airbus

Service Bulletin A320-27-1097, dated October 5, 1996, or Revision

01, dated July 15, 1997, has been accomplished; and for Model A320

series airplanes on which the repair specified in Airbus Service

Bulletin A320-27-1066, Revision 3, dated October 30, 1996, or

Revision 4, dated July 15, 1997, has been accomplished: Inspect

prior to the accumulation of 5,000 flight hours after incorporation

of the repair or modification,

[[Page 49312]]

or within 500 flight hours after the effective date of this AD,

whichever occurs later.

(3) For Airbus Model A320 series airplanes on which Airbus

Modification 22881 has been accomplished, and on which Airbus

Modification 22841 or the modification specified in Airbus Service

Bulletin A320-27-1050 has not been accomplished: Inspect within 500

flight hours after the effective date of this AD.

(b) For airplanes on which no protective half-shell is installed

over area 1 of the left or right inboard flap trunnion: Within 500

flight hours after the effective date of this AD, perform a detailed

visual inspection of areas 1 and 2 of the inboard flap trunnion to

detect wear on the trunnion, in accordance with Airbus Service

Bulletin A320-27-1066, Revision 4, dated July 15, 1997 (for Model

A320 series airplanes), or A320-27-1097, Revision 01, dated July 15,

1997 (for Model A321 series airplanes).

(c) Except as provided by paragraph (d) of this AD: Following

the accomplishment of any inspection required by either paragraph

(a) or (b) of this AD, perform the follow-on repetitive inspections

and/or corrective actions, as applicable, in accordance with Airbus

Service Bulletin A320-27-1066, Revision 4, dated July 15, 1997 (for

Model A320 series airplanes); A320-27-1097, Revision 01, dated July

15, 1997 (for Model A321 series airplanes); or A320-27-1108,

Revision 01, dated July 15, 1997 (for Model A319, A320, and A321

series airplanes); as applicable; at the compliance times specified

in the applicable service bulletin.

(d) If the applicable service bulletin specifies to contact

Airbus for an appropriate action, prior to further flight, repair in

accordance with a method approved by either the Manager,

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

or the Direction Gnrale de l'Aviation Civile (or its delegated

agent).

(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, International Branch, ANM-116.

Operators shall submit 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.

(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.

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

airworthiness directive 96-271-092(B) R1, dated October 8, 1997.

Issued in Renton, Washington, on September 9, 1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 98-24656 Filed 9-14-98; 8:45 am]

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