[Federal Register Volume 61, Number 73 (Monday, April 15, 1996)]
[Proposed Rules]
[Pages 16414-16416]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-9235]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-216-AD]


Airworthiness Directives; Airbus Model A320 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Airbus Model A320 
series airplanes, that currently requires a one-time inspection to 
detect cracking of the floor beams and the side box-beams between 
frames 42 and 43, and repair of cracks. It also requires modification 
of the pressure floor. That AD was prompted by the results of a full-
scale fatigue test. This action would add a new improved modification 
requirement for the pressure floor at section 15 of the fuselage. The 
actions specified by the proposed AD are intended to prevent reduced 
structural integrity of the fuselage.

DATES: Comments must be received by May 28, 1996.

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

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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 -

    On July 9, 1993, the FAA issued AD 93-14-04, amendment 39-8628 (58 
FR 39440, July 23, 1993), applicable to certain Airbus Model A320 
series airplanes, to require a one-time inspection to detect cracking 
of the floor beams and the side box-beams between frames 42 and 43, and 
repair of cracks. It also requires modification of the pressure floor. 
That action was prompted by the results of a full-scale fatigue test, 
which indicated that fatigue cracking can occur in those areas. The 
requirements of that AD are intended to prevent reduced structural 
integrity of the fuselage due to problems associated with fatigue 
cracking. -
    Since the issuance of that AD, Airbus has issued Revision 1 of 
Service Bulletin A320-53-1024, dated March 31, 1994. This service 
bulletin is essentially identical to the original version of the 
service bulletin (which was referenced in AD 93-14-04), but contains 
certain editorial changes. This service bulletin permits further flight 
with cracks in various areas around the fastener/bolt holes, provided 
that those cracks do not exceed certain limits. The Direction Generale 
de l'Aviation Civile (DGAC), which is the airworthiness authority for 
France, classified this service bulletin as mandatory and issued French 
airworthiness directive 92-205-033(B)R1, dated June 22, 1994, in order 
to assure the continued airworthiness of these airplanes in France. -
    In addition, Airbus has issued Revision 3 of Service Bulletin A320-
53-1023, dated March 18, 1994. This service bulletin describes new 
improved procedures for modification of the pressure floor at section 
15 of the fuselage. The modification involves the following actions: -
    1. Removing components of the free-fall extension system of the 
main landing gear and removing specified fasteners from various areas;
    2. Cleaning the fastener holes;
    3. Performing an eddy current (rotary probe) non-destructive test 
inspection of the fastener holes;
    4. Drilling/Reaming the fasteners holes;
    5. Cold expanding the crack-free fastener holes;
    6. Installing new fittings with the oversize fasteners; and
    7. Installing the bell crank assembly and the pulley of the free-
fall extension system of the main landing gear.
    Implementation of the new improved modification will positively 
address the unsafe condition identified as reduced structural integrity 
of the fuselage.
    This airplane model is manufactured in France and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, reviewed all available information, and determined that AD 
action is necessary for products of this type design that are 
certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would supersede AD 93-14-04 to 
continue to require a one-time eddy current and detailed visual 
inspection to detect cracks of various areas around the fastener/bolt 
holes of the pressure floor. However, this proposal would add a new 
improved modification of the pressure floor at section 15 of the 
fuselage. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.
    Operators should note that, unlike the procedures described in 
Airbus Service Bulletin A320-53-1024, Revision 1, dated March 31, 1994, 
this proposed AD would not permit further flight with cracking detected 
in various areas around the fastener/bolt holes. The FAA has determined 
that, due to the safety implications and consequences associated with 
such cracking, all areas around the fastener/bolt holes that are found 
to be cracked must be repaired prior to further flight. The repair 
would be required to be accomplished in accordance with a method 
approved by the FAA.
    Furthermore, the FAA has determined that long term continued 
operational safety will be better assured by design changes to remove 
the source of the problem, rather than by repetitive inspections. Long 
term inspections may not be providing the degree of safety assurance 
necessary for the transport airplane fleet. This, coupled with a better 
understanding of the human factors associated with numerous continual 
inspections, has led the FAA to consider placing less emphasis on 
inspections and more emphasis on design improvements. The proposed 
modification requirement is in consonance with these considerations.
    There are approximately 24 Airbus Model A320 series airplanes of 
U.S. registry would be affected by this proposed AD.
    The inspections that are currently required by AD 93-14-04 take 
approximately 37 work hours per

[[Page 16416]]

airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact on U.S. operators of the 
inspections currently required is estimated to be $53,280, or $2,220 
per airplane.
    The new modification that is proposed in this AD action would take 
approximately 241 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $5,603 per airplane. Based on these figures, the cost 
impact on U.S. operators of the proposed modification requirements of 
this AD is estimated to be $481,512, or $20,063 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    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 USC 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 owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (d) 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, 
accomplish the following:
    (a) Prior to the accumulation of 12,000 total landings, or 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-beams, 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) Modify the pressure floor at section 15 of the fuselage in 
accordance with Airbus Service Bulletin A320-53-1023, Revision 3, 
dated March 18, 1994, at the time specified in either paragraph 
(c)(1) or (c)(2) of this AD, as applicable. Accomplishment of the 
modification terminates the requirements of this AD.
    (1) 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; or Revision 2, dated October 22, 
1993; has been accomplished: Modify prior to the accumulation of 
24,000 total landings, or 6 months after the effective date of this 
AD, whichever occurs later.
    (2) For all other airplanes not subject to paragraph (c)(1) of 
this AD: Modify prior to the accumulation of 18,000 total landings, 
or 6 months after the effective date of this AD, whichever occurs 
later.
    (d) 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, 
FAA, Transport Airplane Directorate. 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.

    (e) 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 April 9, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-9235 Filed 4-12-96; 8:45 am]
BILLING CODE 4910-13-U