[Federal Register Volume 62, Number 48 (Wednesday, March 12, 1997)]
[Proposed Rules]
[Pages 11388-11390]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6085]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-216-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A320 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directive (AD), which would have superseded an existing AD that is 
applicable to certain Airbus Model A320 series airplanes. The existing 
AD currently requires inspections to detect cracking of certain floor 
beams and side box-beams, and repair of cracks. It also requires 
modification of the pressure floor. The previously proposed action 
would have added a requirement to install a new, improved modification 
for the pressure floor. This action revises the previously proposed 
rule by adding a one-time inspection to verify proper clearance between 
the fasteners of the reinforcement bracket and the bellcrank of the 
free-fall extension system of the main landing gear (MLG) and its 
associated tie rod attachment nut. It also would require that a 
different new, improved modification be installed. The actions 
specified by this proposed AD are intended to prevent reduced 
structural integrity of the fuselage, restricted operation of the MLG 
free-fall system and, consequently, reduced ability to use the MLG 
during an emergency.

DATES: Comments must be received by March 31, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-216-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: Tim Backman, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2797; fax (206) 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 95-NM-216-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-103, Attention: Rules 
Docket No. 95-NM-216-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 a notice 
of proposed rulemaking (NPRM) in the Federal Register on April 15, 1996 
(61 FR 16414). That NPRM would have superseded AD 93-14-04, amendment 
39-8628 (58 FR 39440, July 23, 1993), to continue to require a one-time 
eddy current and detailed visual inspections to detect cracks of 
various areas around the fastener/bolt holes of the pressure floor. 
That NPRM also would have added a requirement to install a new, 
improved modification requirement for the pressure floor at section 15 
of the fuselage. That NPRM was prompted by the results of a full-scale 
fatigue test, which indicated that fatigue cracking can occur in those 
areas. Such fatigue cracking, if not detected and corrected in a timely 
manner, could result in reduced structural integrity of the fuselage.

Actions Since Issuance of Originally Proposed NPRM

    Since the issuance of that NPRM, the Direction G\n\rale de 
l'Aviation Civile (DGAC), which is the airworthiness authority for 
France, notified the FAA that an additional unsafe condition may exist 
on Airbus Model A320 series airplanes that were modified in accordance 
with Airbus Service Bulletin A320-53-1023, Revision 3, dated March 18, 
1994. That modification was considered to be terminating action for the 
repetitive inspection requirements of AD 93-14-04. The DGAC advises 
that, following accomplishment of the subject modification, it received 
reports indicating that interference could occur between the fasteners 
of the reinforcement bracket and the bellcrank of the free-fall 
extension system of the main landing gear (MLG) and its associated tie 
rod attachment nut. This condition, if not corrected, could restrict 
operation of the free-fall system of the MLG and, consequently, result 
in reduced ability to use the MLG during an emergency.

[[Page 11389]]

Description of Revised Service Information

    Airbus has issued Revision 7 of Service Bulletin A320-53-1023, 
dated November 3, 1995, which describes procedures for installation of 
a new, improved modification of the pressure floor at section 15 of the 
fuselage. This revision differs from Revision 3 of the service bulletin 
in the following two aspects:
    1. It includes updated installation procedures for the fasteners 
located adjacent to the bell crank lever of the free-fall extension 
system of the MLG; and
    2. It includes additional procedures for reworking the attachment 
bracket located above the pressure diaphragm.
    Accomplishment of this modification would eliminate the need for 
the one-time eddy current and detailed visual inspections. Installation 
of the new, improved modification will positively address the unsafe 
condition identified as reduced structural integrity of the fuselage, 
and restricted operation of the MLG free fall system.
    Airbus also has issued All Operators Telex (AOT) 53-08, Revision 
01, dated January 15, 1996, which concerns only certain airplanes. The 
service bulletin describes procedures for performing a one-time 
inspection to verify proper clearance between the fasteners of the 
reinforcement bracket and the bellcrank of the free-fall extension 
system of the MLG and its associated tie rod attachment nut. The AOT 
also describes procedures for reinstalling the reinforcement bracket 
fasteners, or, under certain conditions, reworking the bellcrank lever 
and fasteners, if necessary.
    The DGAC classified the Airbus service bulletin and AOT as 
mandatory and issued French airworthiness directive 96-053-077(B), 
dated March 13, 1996, in order to assure the continued airworthiness of 
these airplanes in France.

Explanation of Changes Made to Proposal

    Based on this new information, the FAA has determined that the 
previously issued proposal must be revised in order to adequately 
address the unsafe condition presented by interference problems 
associated with accomplishment of the procedures contained in Airbus 
Service Bulletin A320-53-1023, up to and including Revision 6, dated 
September 4, 1995.
    Accordingly, the FAA has added a new paragraph (c) to this 
supplemental NPRM, which would require the accomplishment of the 
procedures specified in Airbus AOT 53-08, Revision 01, dated January 
15, 1996, described previously. In addition, paragraph (c) of the 
supplemental NPRM also would include a requirement to accomplish the 
modification specified in Revision 7 of Airbus Service Bulletin A320-
53-1023, described previously.
    The FAA also has revised paragraph (c) of the originally-proposed 
NPRM [designated as paragraph (d) in this supplemental NPRM] to 
reference Revision 7 of Airbus Service Bulletin A320-53-1023 as the 
appropriate source of service information for modification of the 
pressure floor.
    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 24 Airbus Model A320 series airplanes of 
U.S. registry that would be affected by this proposed AD.
    The inspections that are currently required by AD 93-14-04 take 
approximately 37 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required inspections on U.S. operators is 
estimated to be $53,280, or $2,220 per airplane.
    The new inspection that is proposed by this AD action would take 
approximately 11 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the new inspection on U.S. operators is estimated to be 
$15,840, or $660 per airplane.
    The new modification that is proposed by this AD action would take 
approximately 142 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will be supplied by the 
manufacturer at no cost to the operators. Based on these figures, the 
cost impact of the modification on U.S. operators is estimated to be 
$204,480, or $8,520 per airplane.
    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.

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 removing amendment 39-8628 (58 FR 
39440, July 23, 1993), and by adding a new airworthiness directive (AD) 
to read as follows:

Airbus Industrie: Docket 95-NM-216-AD. Supersedes AD 93-14-04, 
amendment 39-8628.

    Applicability: Model A320 series airplanes, manufacturer's 
serial numbers 002 through 008 inclusive, 010 through 078 inclusive, 
and 080 through 107 inclusive; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the

[[Page 11390]]

owner/operator must request approval for an alternative method of 
compliance in accordance with paragraph (f) 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 prevent reduced structural integrity of the fuselage, 
restricted operation of the main landing gear (MLG) free-fall 
system, and, consequently, reduced ability to use the MLG during an 
emergency, accomplish the following:
    (a) Prior to the accumulation of 12,000 total landings, or 
within 6 months after August 23, 1993 (the effective date of AD 93-
14-04, amendment 39-8628), whichever occurs later, accomplish the 
requirements of paragraphs (a)(1) and (a)(2) of this AD, in 
accordance with Airbus Industrie Service Bulletin A320-53-1024, 
dated September 23, 1992, or Revision 1, dated March 31, 1994. As of 
the effective date of this new AD, only Revision 1 of this service 
bulletin shall be used.
    (1) Conduct an eddy current inspection to detect cracking around 
the fastener/bolt holes at the top horizontal flange of the floor 
beams and side box-beams, at the two sides of the pressure floor, 
and at the vertical integral stiffener of the side box-beams; and
    (2) Conduct a detailed visual inspection to detect cracking 
around the fastener/bolt holes at the fillet radius and riveted area 
of the top outboard flange of the side box-beam, and at the flange-
corner radius of the slanted inboard flange of the side box-beam and 
fittings.
    (b) If any crack is detected during the inspections required by 
paragraph (a) of this AD, prior to further flight, repair the crack 
in accordance with a method approved by the Manager, Standardization 
Branch, ANM-113, FAA, Transport Airplane Directorate.
    (c) For airplanes on which the modification specified in Airbus 
Service Bulletin A320-53-1023, dated September 23, 1992, as amended 
by Service Bulletin Change Notice 0A, dated January 20, 1993; 
Revision 1, dated March 23, 1993; Revision 2, dated October 22, 
1993; Revision 3, dated March 18, 1994; Revision 4, dated September 
30, 1994; Revision 5, dated February 28, 1995; or Revision 6, dated 
September 4, 1995; has been accomplished: Accomplish paragraphs 
(c)(1) and (c)(2) of this AD.
    (1) Prior to the accumulation of 1,000 landings after the 
effective date of this AD, perform a one-time inspection to verify 
proper clearance between the fasteners of the reinforcement bracket 
and the bellcrank of the free-fall extension system of the MLG and 
its associated tie rod attachment nut, in accordance with Airbus All 
Operators Telex (AOT) 53-08, Revision 01, dated January 15, 1996.
    (i) If the minimum clearance is greater than 3 mm (0.118 inch) 
and no evidence of interference is detected, within 60 months 
following accomplishment of the inspection required by paragraph 
(c)(1) of this AD, reinstall the reinforcement bracket fasteners in 
accordance with Airbus Service Bulletin A320-53-1023, Revision 7, 
dated November 3, 1995.
    (ii) If the minimum clearance is 3 mm (0.118 inch) or less, and 
no evidence of interference is detected, within 18 months following 
accomplishment of the inspection required by paragraph (c)(1) of 
this AD, reinstall the reinforcement bracket fasteners in accordance 
with Airbus Service Bulletin A320-53-1023, Revision 7, dated 
November 3, 1995.
    (iii) If any interference is detected, prior to further flight, 
accomplish either paragraph (c)(1)(iii)(A) or (c)(1)(iii)(B) of this 
AD.
    (A) Reinstall the reinforcement bracket fasteners in accordance 
with Airbus Service Bulletin A320-53-1023, Revision 7, dated 
November 3, 1995; or
    (B) Rework the bellcrank lever and fasteners in accordance with 
Airbus AOT 53-08, Revision 01, dated January 15, 1996. Within 60 
months following accomplishment of the rework, reinstall the 
reinforcement bracket fasteners in accordance with Airbus Service 
Bulletin A320-53-1023, Revision 7, dated November 3, 1995.
    (2) Prior to the accumulation of 24,000 total landings, or 6 
months after the effective date of this AD, whichever occurs later, 
modify the pressure floor at section 15 of the fuselage in 
accordance with Airbus Service Bulletin A320-53-1023, Revision 7, 
dated November 3, 1995. Accomplishment of the modification 
terminates the requirements of this AD.
    (d) For airplanes on which the modification specified in Airbus 
Service Bulletin A320-53-1023, dated September 23, 1992, as amended 
by Service Bulletin Change Notice 0A, dated January 20, 1993; 
Revision 1, dated March 23, 1993; Revision 2, dated October 22, 
1993; Revision 3, dated March 18, 1994; Revision 4, dated September 
30, 1994; Revision 5, dated February 28, 1995; or Revision 6, dated 
September 4, 1995; has not been accomplished: Prior to the 
accumulation of 18,000 total landings, or within 6 months after the 
effective date of this AD, whichever occurs later, modify the 
pressure floor at section 15 of the fuselage in accordance with 
Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 
1995. Accomplishment of the modification terminates the requirements 
of this AD.
    (e) Accomplishment of the modification of the pressure floor at 
section 15 of the fuselage in accordance with Airbus Service 
Bulletin A320-53-1023, Revision 7, dated November 3, 1995, 
constitutes terminating action for the requirements of this AD.
    (f) 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, Standardization Branch, ANM-113. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.
    (g) 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.

    Issued in Renton, Washington, on March 5, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-6085 Filed 3-11-97; 8:45 am]
BILLING CODE 4910-13-U