[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]
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