[Federal Register Volume 63, Number 178 (Tuesday, September 15, 1998)]
[Proposed Rules]
[Pages 49309-49312]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24656]


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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]
BILLING CODE 4910-13-U