[Federal Register: January 24, 2008 (Volume 73, Number 16)]
[Proposed Rules]
[Page 4129-4131]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24ja08-38]
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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]
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: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede an existing airworthiness
directive (AD) that applies to certain Airbus Model A319, A320, and
A321 series airplanes equipped with certain Litton air data inertial
reference units (ADIRUs). The existing 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
proposed AD would require those modifications on additional airplanes.
This proposed AD would also require replacing all three ADIRUs with
improved ADIRUs. This proposed AD also adds Model A318 series airplanes
to the applicability. This proposed 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 proposing 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: We must receive comments on this proposed AD by February 25,
2008.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov.
Follow the instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
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 proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
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:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0046;
Directorate Identifier 2007-NM-270-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov
, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
On December 12, 2003, we issued AD 2003-26-03, amendment 39-13399
(68 FR 74172, December 23, 2003), for certain Airbus Model A319, A320,
and A321 series airplanes equipped with certain Litton air data
inertial reference units (ADIRUs). That AD requires modifying the shelf
(floor panel) above ADIRU 3, and, for certain airplanes, modifying the
polycarbonate guard that covers the ADIRUs, and the ladder located in
the avionics compartment, as applicable. That AD resulted from reports
that ``NAV IR FAULT'' messages have occurred during takeoff due to
failure of ADIRU 3 on several Model A319, A320, and A321 series
airplanes. We issued that AD to prevent failure of ADIRU 3 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.
Actions Since Existing AD Was Issued
Since we issued AD 2003-26-03, the European Aviation Safety Agency
(EASA), which is the Technical Agent for the Member States of the
European Union, notified us that further analysis has shown that
modifying the ADIRU shelf has not sufficiently addressed the unsafe
condition. The clearance between the shelf and ADIRUs is still too
small. Consequently, vibration during takeoff could cause the shelf to
hit the top of an ADIRU, leading to loss of parameters (attitude,
vertical speed, ground speed, etc.). The EASA has determined that, in
addition to
[[Page 4130]]
modifying the ADIRU shelf, all three ADIRUs must be replaced with
improved ADIRUs that introduce a more robust shock resistance to
adequately address the unsafe condition. The EASA has also determined
that the unsafe condition exists on certain Model A318 series
airplanes.
Relevant Service Information
Airbus has issued Service Bulletin A320-34-1350, dated March 20,
2006. The service bulletin describes procedures for replacing all three
ADIRUs with improved ADIRUs having part number 465020-0303-0316, which
introduce a more robust shock resistance and new magnetic variation
tables.
Airbus has also issued Service Bulletin A320-25-1248, Revision 01,
dated April 16, 2003. The procedures in Revision 01 of the service
bulletin are essentially the same as those in the original issue of the
service bulletin, dated February 16, 2001. Revision 1 of the service
bulletin adds airplanes to the effectivity of the service bulletin.
Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition. The EASA mandated
the service information and issued airworthiness directive 2007-0217,
dated August 9, 2007, to ensure the continued airworthiness of these
airplanes in the European Union.
FAA's Determination and Requirements of the Proposed AD
These airplanes are manufactured in France and are 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. As described in FAA
Order 8100.14A, ``Interim Procedures for Working with the European
Community on Airworthiness Certification and Continued Airworthiness,''
dated August 12, 2005, the EASA has kept the FAA informed of the
situation described above. We have examined the EASA's findings,
evaluated all pertinent information, and determined that AD action is
necessary for airplanes of this type design that are certificated for
operation in the United States.
This proposed AD would supersede AD 2003-26-03 and retain the
requirements of the existing AD. This proposed AD would also require
accomplishing the actions specified in the service information
described previously.
Change to Existing AD
This proposed AD would retain all requirements of AD 2003-26-03.
Since AD 2003-26-03 was issued, the AD format has been revised, and
certain paragraphs have been rearranged. As a result, the requirement
in paragraph (a) of AD 2003-26-03 corresponds to paragraph (f) of this
proposed AD.
Costs of Compliance
This proposed AD would affect about 658 airplanes of U.S. registry.
The actions that are required by AD 2003-26-03 and retained in this
proposed 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 proposed actions would 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 proposed 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 proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the 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. 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 proposed 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, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends Sec. 39.13 by
removing amendment 39-13399 (68 FR 74172, December 23, 2003) and adding
the following new airworthiness directive (AD):
Airbus: Docket No. FAA-2008-0046; Directorate Identifier 2007-NM-
270-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by February
25, 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.
Unsafe Condition
(d) This AD results from reports that ``NAV IR FAULT'' messages
have occurred during takeoff due to failure of an ADIRU and
[[Page 4131]]
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 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.
Alternative Methods of Compliance (AMOCs)
(i)(1) The Manager, International Branch, ANM-116, Transport
Airplane Directorate, FAA, has the authority to approve AMOCs for
this AD, if requested in accordance with the procedures found in 14
CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
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.
Issued in Renton, Washington, on January 14, 2008.
Stephen P. Boyd,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service.
[FR Doc. E8-1135 Filed 1-23-08; 8:45 am]
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