Document ID: FAA-2008-0046-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Airbus Model A318, A319, A320, and A321 Series Airplanes Equipped With Certain Northrop Grumman (Formerly Litton) Air Data Inertial Reference Units
Posted Date: 2008-08-28T04:00Z

[Federal Register: August 28, 2008 (Volume 73, Number 168)]
[Rules and Regulations]               
[Page 50709-50711]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28au08-4]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0046; Directorate Identifier 2007-NM-270-AD; 
Amendment 39-15650; AD 2008-17-12]
RIN 2120-AA64

 
Airworthiness Directives; Airbus Model A318, A319, A320, and A321 
Series Airplanes Equipped With Certain Northrop Grumman (Formerly 
Litton) Air Data Inertial Reference Units

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Airbus Model A319, A320, and A321 series 
airplanes equipped with certain Litton air data inertial reference 
units (ADIRUs). That AD currently requires modifying the shelf (floor 
panel) above ADIRU 3, modifying the polycarbonate guard that covers the 
ADIRUs for certain airplanes, and modifying the ladder located in the 
avionics compartment for certain airplanes. This new AD requires those 
modifications on additional airplanes. This new AD also requires 
replacing all three ADIRUs with improved ADIRUs. This new AD also adds 
Model A318 series airplanes to the applicability. This AD results from 
reports that ``NAV IR FAULT'' messages have occurred during takeoff due 
to failure of an ADIRU and subsequent analysis showing that the shelf 
modification has not sufficiently addressed failure of an ADIRU. We are 
issuing this AD to prevent failure of an ADIRU during flight, which 
could result in loss of one source of critical attitude and airspeed 
data and reduce the ability of the flightcrew to control the airplane.

DATES: This AD becomes effective October 2, 2008.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of October 2, 
2008.
    On January 27, 2004 (68 FR 74172, December 23, 2003), the Director 
of the Federal Register approved the incorporation by reference of a 
certain publication.

ADDRESSES: For service information identified in this AD, contact 
Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Tim Dulin, Aerospace Engineer, 
International Branch, ANM-116, Transport Airplane Directorate, FAA, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
227-2141; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 2003-26-03, amendment 
39-13399 (68 FR 74172, December 23, 2003). The existing AD applies to 
certain Airbus Model A319, A320, and A321 series airplanes equipped 
with certain Litton air data inertial reference units (ADIRUs). That 
NPRM was published in the Federal Register on January 24, 2008 (73 FR 
4129). That NPRM proposed to continue to require modifying the shelf 
(floor panel) above ADIRU 3, modifying the polycarbonate guard that 
covers the ADIRUs for certain airplanes, and modifying the ladder 
located in the avionics compartment for certain airplanes. That NPRM 
also proposed to require those modifications on additional airplanes. 
That NPRM also proposed to require replacing all three ADIRUs with 
improved ADIRUs. That NPRM also proposed to add Model

[[Page 50710]]

A318 series airplanes to the applicability.

Actions Since NPRM Was Issued

    Airbus has issued Service Bulletin A320-34-1350, Revision 01, dated 
December 12, 2007. In the NPRM, we referred to the original issue of 
the service bulletin, dated March 20, 2006, as the appropriate source 
of service information for replacing the ADIRUs with new, improved 
ADIRUs. The procedures in Revision 01 of the service bulletin are 
essentially the same as those in the original issue of the service 
bulletin. Therefore, we have revised paragraph (h) of this AD to also 
refer to Revision 01 of the service bulletin.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comment that has been 
received on the NPRM.

Request to Revise the Applicability

    Airbus requests that we revise the applicability of the NPRM to 
also exempt airplanes equipped with three ADIRUs having P/N 465020-
0303-0316 on which Airbus Service Bulletin A320-25-1248 has been 
applied in service.
    We agree that this AD does not apply to airplanes equipped with 
three ADIRUs having P/N 465020-0303-0316 on which Airbus Service 
Bulletin A320-25-1248 was incorporated in service. We have revised 
paragraph (c) of this AD accordingly.

Conclusion

    We have carefully reviewed the available data, including the 
comment that has been received, and determined that air safety and the 
public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    This AD affects about 658 airplanes of U.S. registry.
    The actions that are required by AD 2003-26-03 and retained in this 
AD take about 4 work hours per airplane, at an average labor rate of 
$80 per work hour. Required parts cost about $300 per airplane. Based 
on these figures, the estimated cost of the currently required actions 
for U.S. operators is $407,960, or $620 per airplane.
    The new actions take about 3 work hours per airplane, at an average 
labor rate of $80 per work hour. The manufacturer states that it will 
supply the required parts to operators at no cost. Based on these 
figures, the estimated cost of the new actions specified in this AD for 
U.S. operators is $157,920, or $240 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-13399 (68 FR 74172, December 23, 2003) and by 
adding the following new airworthiness directive (AD):

2008-17-12 Airbus: Amendment 39-15650. Docket No. FAA-2008-0046; 
Directorate Identifier 2007-NM-270-AD.

Effective Date

    (a) This AD becomes effective October 2, 2008.

Affected ADs

    (b) This AD supersedes AD 2003-26-03.

Applicability

    (c) This AD applies to Airbus Model A318, A319, A320, and A321 
series airplanes, certificated in any category; equipped with at 
least one Northrop Grumman (formerly Litton) air data inertial 
reference unit (ADIRU), part number (P/N) 465020-0303-0307, -0308, -
0309, -0312, -0314, -0315, or -0316; except airplanes equipped with 
three ADIRUs having P/N 465020-0303-0316 and on which Airbus 
Modification 30650 or 30872 has been incorporated in production, or 
on which Airbus Service Bulletin A320-25-1248 has been applied in 
service.

Unsafe Condition

    (d) This AD results from reports that ``NAV IR FAULT'' messages 
have occurred during takeoff due to failure of an ADIRU and 
subsequent analysis showing that the shelf modification has not 
sufficiently addressed failure of an ADIRU. We are issuing this AD 
to prevent failure of an ADIRU during flight, which could result in 
loss of one source of critical attitude and airspeed data and reduce 
the ability of the flightcrew to control the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Restatement of Requirements of AD 2003-26-03

Modification

    (f) For Model A319, A320, and A321 series airplanes, equipped 
with any Litton ADIRU installed in accordance with Airbus 
Modification 24852, 25108, 25336, 26002, or 28218: Within 2 years 
after January 27, 2004 (the effective date of AD 2003-26-03), do the 
modifications specified in paragraphs (f)(1), (f)(2), and (f)(3) of 
this AD, as applicable, in accordance with paragraphs A. through D. 
of the Accomplishment Instructions of Airbus Service Bulletin A320-
25-1248, dated February 16, 2001; or Airbus Service Bulletin

[[Page 50711]]

A320-25-1248, Revision 01, dated April 16, 2003; as applicable.
    (1) For all airplanes: Modify the shelf (floor panel) above 
ADIRU 3 by installing shims between the shelf and the webs of the 
shelf support structure.
    (2) For airplanes with Airbus Modification 25900P3941 or Airbus 
Service Bulletin A320-25-1200 accomplished as of January 27, 2004: 
Modify the polycarbonate guard (umbrella) protecting the ADIRUs by 
installing shims between the guard and the shelf support structure.
    (3) For airplanes with Airbus Modification 23027P2852 or Airbus 
Service Bulletin A320-52-1038 accomplished as of January 27, 2004: 
Modify the ladder located in the avionics compartment by machining 
the slot at the foot of the ladder to increase the depth by 0.236 
inch.

New Requirements of This AD

Modification for Certain Airplanes

    (g) For all airplanes equipped with any ADIRU installed in 
accordance with Airbus Modification 31070, 31742, or 35517, except 
airplanes on which Airbus Modification 30650 or 30872 has been 
accomplished in production: Within 46 months after the effective 
date of this AD, modify the ADIRU shelf supports by accomplishing 
all of the applicable actions specified in the Accomplishment 
Instructions of Airbus Service Bulletin A320-25-1248, Revision 01, 
dated April 16, 2003.

Replacement of ADIRUs

    (h) For all airplanes except those on which Airbus Modification 
35517 has been incorporated in production: Within 46 months after 
the effective date of this AD, replace all three ADIRUs with 
improved ADIRUs having P/N 465020-0303-0316 in accordance with the 
Accomplishment Instructions of Airbus Service Bulletin A320-34-1350, 
dated March 20, 2006; or Airbus Service Bulletin A320-34-1350, 
Revision 01, dated December 12, 2007.

Alternative Methods of Compliance (AMOCs)

    (i) The Manager, International Branch, ANM-116, Transport 
Airplane Directorate, FAA, has the authority to approve AMOCs for 
this AD, if requested using the procedures found in 14 CFR 39.19. 
Send information to ATTN Tim Dulin, Aerospace Engineer, 
International Branch, ANM-116, Transport Airplane Directorate, FAA, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 227-2141; fax (425) 227-1149. Before using any approved AMOC 
on any airplane to which the AMOC applies, notify your appropriate 
principal inspector (PI) in the FAA Flight Standards District Office 
(FSDO), or lacking a PI, your local FSDO.

Related Information

    (j) European Aviation Safety Agency airworthiness directive 
2007-0217, dated August 9, 2007, also addresses the subject of this 
AD.

Material Incorporated by Reference

    (k) You must use service information identified in Table 1 of 
this AD, as applicable, to perform the actions that are required by 
this AD, unless the AD specifies otherwise.

                                 Table 1--All Material Incorporated by Reference
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           Service bulletin                        Revision level                            Date
----------------------------------------------------------------------------------------------------------------
Airbus Service Bulletin A320-25-1248..  Original...........................  February 16, 2001.
Airbus Service Bulletin A320-25-1248..  01.................................  April 16, 2003.
Airbus Service Bulletin A320-34-1350..  Original...........................  March 20, 2006.
Airbus Service Bulletin A320-34-1350..  01.................................  December 12, 2007.
----------------------------------------------------------------------------------------------------------------

    (1) The Director of the Federal Register approved the 
incorporation by reference of the documents identified in Table 2 of 
this AD in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

                                 Table 2--New Material Incorporated by Reference
----------------------------------------------------------------------------------------------------------------
           Service bulletin                        Revision level                            Date
----------------------------------------------------------------------------------------------------------------
Airbus Service Bulletin A320-25-1248..  01.................................  April 16, 2003.
Airbus Service Bulletin A320-34-1350..  Original...........................  March 20, 2006.
Airbus Service Bulletin A320-34-1350..  01.................................  December 12, 2007.
----------------------------------------------------------------------------------------------------------------

    (2) On January 27, 2004 (68 FR 74172, December 23, 2003), the 
Director of the Federal Register approved the incorporation by 
reference of Airbus Service Bulletin A320-25-1248, dated February 
16, 2001.
    (3) Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac 
Cedex, France, for a copy of this service information. You may 
review copies at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, call 202-741-6030, or go to: http://
www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on August 6, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-19138 Filed 8-27-08; 8:45 am]

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