[Federal Register Volume 72, Number 65 (Thursday, April 5, 2007)]
[Proposed Rules]
[Pages 16749-16752]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-6343]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27776; Directorate Identifier 2006-NM-170-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A318, A319, A320, and A321 
Airplanes

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 all Airbus Model A318-100, A319-100, 
A320-200, A321-100, and A321-200 series airplanes, and Model A320-111 
airplanes. The existing AD currently requires an inspection to 
determine whether certain braking and steering control units (BSCUs) 
are installed or have ever been installed. For airplanes on which 
certain BSCUs are installed or have ever been installed, the existing 
AD requires an inspection of the nose landing gear (NLG) upper support 
and corrective action if necessary, and a check of the NLG strut 
inflation pressure and an adjustment if necessary. For some of these 
airplanes, the existing AD also requires a revision to the aircraft 
flight manual to incorporate an operating procedure to recover normal 
steering in the event of a steering failure. This proposed AD would 
require repetitive inspections of the NLG upper support, and related 
investigative/corrective actions in accordance with new service 
information; and would remove the one-time inspection that was required 
by the existing AD. This proposed AD also would provide an optional 
terminating action for the repetitive inspections. This proposed AD 
results from a report of an incident where an airplane landed with the 
NLG turned 90 degrees from centerline, and from additional reports of 
NLG upper support anti-rotation lugs rupturing in service. We are 
proposing this AD to prevent landings with the NLG turned 90 degrees 
from centerline, which could result in reduced controllability of the 
airplane.

DATES: We must receive comments on this proposed AD by May 7, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, 
France, for service information identified in this proposed AD.

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

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``Docket No. 
FAA-2007-27776; Directorate Identifier 2006-NM-170-AD'' at the 
beginning of your comments. We specifically invite comments on the 
overall regulatory, economic, environmental, and energy aspects of the 
proposed AD. We will consider all comments received by the closing date 
and may amend the proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    On November 16, 2005, we issued AD 2005-24-06, amendment 39-14386 
(70 FR 70715, November 23, 2005), for all Airbus Model A318-100, A319-
100, A320-200, A321-100, and A321-200 series airplanes, and Model A320-
111 airplanes. That AD requires an inspection to determine whether 
certain braking and steering control units (BSCUs) are installed or 
have ever been installed. For airplanes on which certain BSCUs are 
installed or have ever been installed, that AD requires an inspection 
of the nose landing gear (NLG) upper support and corrective action if 
necessary, and a check of the NLG strut inflation pressure and an 
adjustment if necessary. For some of these airplanes, that AD also 
requires a revision to the aircraft flight manual (AFM) to incorporate 
an operating procedure to recover normal steering in the event of a 
steering failure. That AD resulted from a report of an incident where 
an airplane landed with the NLG turned 90 degrees from centerline. We 
issued that AD to prevent landings with the NLG turned 90 degrees from 
centerline, which could result in reduced controllability of the 
airplane.

Actions Since Existing AD Was Issued

    Since we issued AD 2005-24-06, several additional NLG upper support 
anti-rotation lugs have ruptured in service, which could lead to the 
inability to retract the NLG and possible landings with the nose wheel 
turned 90 degrees from centerline. Investigations showed that the 
affected airplanes were all equipped with enhanced manufacturing and 
maintainability (EMM) BSCU (Standard L4.1 and L4.5). The NLG shock 
absorber was also found to be over-pressurized on some of these 
airplanes, which resulted in increased loads on the upper support. As a 
result,

[[Page 16750]]

the manufacturer developed a repetitive boroscope inspection of the NLG 
upper support lugs and cylinder lugs to replace the one-time 
inspection, and an optional terminating action for the repetitive 
inspections.

Relevant Service Information

    Airbus has issued Service Bulletin A320-32-1310, dated February 8, 
2006. The service bulletin describes procedures for doing a records 
review to determine if the airplane is equipped with or has ever been 
equipped with an EMM BSCU. For those airplanes that are equipped with 
an EMM BSCU, the service bulletin describes procedures for doing a 
repetitive special detailed inspection (boroscopic) for broken or 
cracked NLG upper support lugs and missing cylinder lugs, and related 
investigative/corrective actions. The related investigative/corrective 
actions follow:
     If the upper support anti-rotation lugs are broken or 
cracked, or if a cylinder lug is missing: Do a pressure check of the 
NLG shock absorber (weight on and weight off wheels); report the 
measured pressure, `H' dimension, temperature, and boroscopic 
inspection findings to Airbus for further assessment; and restore the 
NLG in accordance with Airbus recommendations.
     If there are no findings: At the initial threshold 
inspection, do a servicing check (weight on wheels) of the NLG shock 
absorber. If the pressure is not within permissible tolerance, adjust 
the pressure and do the servicing check again with the weight off the 
wheels. If the pressure is not within permissible tolerance with the 
weight off the wheels, do a full service of the NLG shock absorber. The 
service bulletin states that it is not necessary to do these actions 
again at the repetitive intervals unless there is a finding during the 
boroscopic inspection.
    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, mandated the 
service information and issued EASA Airworthiness Directive 2006-0174, 
dated June 21, 2006, to ensure the continued airworthiness of these 
airplanes in the European Union.

FAA's Determination and Requirements of the Proposed AD

    These airplane models 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, EASA has kept the FAA informed of the situation 
described above. We have examined 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 2005-24-06 and would retain the 
requirements of the existing AD, except for the boroscope inspection 
required within 90 days specified in paragraph (i)(2), and the repair 
requirements of paragraph (j) of AD 2005-24-06. This proposed AD would 
also require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Differences among the Proposed AD, the EASA Airworthiness Directive, 
and the Service Bulletin.''

Differences Among the Proposed AD, the EASA Airworthiness Directive, 
and the Service Bulletin

    The service bulletin specifies to contact the manufacturer for 
further assessment of the reported measured pressure, `H' dimension, 
temperature, and boroscope inspection findings of the NLG shock 
absorber, but this proposed AD does not require such reporting and 
assessment. The service bulletin also specifies restoring the NLG in 
accordance with Airbus recommendations, but this proposed AD would 
require restoring the NLG in accordance with a method approved by the 
FAA or the EASA (or its delegated agent).

Changes to Existing AD

    We have changed the airplane model designations in the 
applicability and in paragraph (f), ``Records Review,'' of this 
proposed AD to be consistent with the parallel EASA airworthiness 
directive.
    We have clarified paragraph (f) of this proposed AD to refer to 
BSCU standard L4.1 and L4.5, and added that Airbus Service Bulletin 
A320-32-1310, dated February 8, 2006, is one approved method for doing 
the records review.

Costs of Compliance

    This proposed AD would affect about 720 airplanes of U.S. registry. 
The following table provides the estimated costs for U.S. operators to 
comply with this proposed AD. The average labor rate is $80 per work 
hour.

                                                 Estimated Costs
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             Action                 Work hours            Parts          Cost per airplane        Fleet cost
----------------------------------------------------------------------------------------------------------------
Records review (required by AD                 1  None................  $80................  $57,600.
 2005-24-06).
AFM revision (required by AD                   1  None................  $80................  $57,600.
 2005-24-06).
Special detailed inspection in                 1  None................  $80,...............  $57,600, per
 accordance with new service                                            per inspection        inspection cycle.
 information (new proposed                                               cycle.
 action).
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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

[[Page 16751]]

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 39-14386 (70 FR 70715, November 23, 2005) and adding 
the following new airworthiness directive (AD):

Airbus: Docket No. FAA-2007-27776; Directorate Identifier 2006-NM-
170-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by May 7, 
2007.

Affected ADs

    (b) This AD supersedes AD 2005-24-06.

Applicability

    (c) This AD applies to all Airbus Model A318, A319, A320, and 
A321 airplanes.

Unsafe Condition

    (d) This AD results from a report of an incident where an 
airplane landed with the nose landing gear (NLG) turned 90 degrees 
from centerline, and from additional reports of NLG upper support 
anti-rotation lugs rupturing in service. We are issuing this AD to 
prevent landings with the NLG turned 90 degrees from centerline, 
which could result in reduced controllability of 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 Certain Requirements of AD 2005-24-06

Records Review

    (f) Within 5 days after November 30, 2005 (the effective date of 
AD 2005-24-06), perform a records review to determine whether the 
airplane is equipped with or has ever been equipped with an enhanced 
manufacturing and maintainability (EMM) braking and steering control 
unit (BSCU) part number (P/N) E21327001 (standard L4.1, installed by 
Airbus Modification 26965, or Airbus Service Bulletin A320-32-1912) 
or P/N E21327003 (standard L4.5, installed by Airbus Modification 
33376, or Airbus Service Bulletin A320-32-1261). Airbus Service 
Bulletin A320-32-1310, dated February 8, 2006, is one approved 
method for doing the records review.
    (g) For airplanes on which a records review required by 
paragraph (f) of this AD conclusively determines that the airplane 
is not and never has been equipped with a BSCU P/N E21327001 or P/N 
E21327003, no further action is required by this AD.

Airplane Flight Manual (AFM) Revision

    (h) For airplanes that are not specified in paragraph (g) of 
this AD and on which Airbus Modification 31152 has not been 
incorporated in production (i.e., applicable only to aircraft with 
steering powered by the green hydraulic system): Within 10 days 
after November 30, 2005, revise the Limitation Section of the Airbus 
A318/319/320/321 Aircraft Flight Manual (AFM) to include the 
following information. This may be done by inserting a copy of this 
AD into the AFM:

    ``The ECAM message, in case of a nose wheel steering failure, 
will be worded as follows:

--``WHEEL N/W STRG FAULT'' for aircraft with the FWC E3 and 
subsequent standards
--``WHEEL N.W STEER FAULT'' for aircraft with the FWC E2 Standard.

     If the L/G SHOCK ABSORBER FAULT ECAM caution is 
triggered at any time in flight, and the WHEEL N/W STRG FAULT ECAM 
caution is triggered after the landing gear extension:
     When all landing gear doors are indicated closed on 
ECAM WHEEL page, reset the BSCU:

    --A/SKID&N/W STRG--OFF THEN ON

     If the WHEEL N/W STRG FAULT ECAM caution is no longer 
displayed, this indicates a successful nose wheel re-centering and 
steering recovery.

     Rearm the AUTO BRAKE, if necessary.

     If the WHEEL N/W STRG FAULT ECAM caution remains 
displayed, this indicates that the nose wheel steering remains lost, 
and that the nose wheels are not centered.

    --During landing, delay nose wheel touchdown for as long as 
possible.
    --Refer to the ECAM STATUS.

     If the WHEEL N/W STRG FAULT ECAM caution appears, 
without the L/G SHOCK ABSORBER FAULT ECAM caution:

    --No specific crew action is requested by the WHEEL N/W STRG 
FAULT ECAM caution procedure.
    --Refer to the ECAM STATUS.''

    Note 1: When a statement identical to that in paragraph (h) of 
this AD has been included in the general revisions of the AFM, the 
general revisions may be inserted into the AFM, and the copy of this 
AD may be removed from the AFM.

New Requirements of This AD

Inspection Thresholds

    (i) For airplanes that are not specified in paragraph (g) of 
this AD, at the earlier of the times specified in paragraphs (i)(1) 
and (i)(2) of this AD: Do a special detailed inspection (boroscopic) 
for broken or cracked NLG upper support lugs and missing cylinder 
lugs, and do all applicable related investigative/corrective actions 
before further flight. Do all actions in accordance with Airbus 
Technical Note 957.1901/05, dated October 18, 2005, or the 
Accomplishment Instructions of Airbus Service Bulletin A320-32-1310, 
dated February 8, 2006. After the effective date of this AD, only 
Airbus Service Bulletin A320-32-1301, dated February 8, 2006, may be 
used. Where the service bulletin specifies that restoring the NLG is 
necessary in accordance with Airbus recommendations, this AD 
requires restoring the NLG in accordance with a method approved by 
the Manager, International Branch, ANM-116, Transport Airplane 
Directorate, FAA; or the European Aviation Safety Agency (EASA) (or 
its delegated agent). Repeat the inspection thereafter at the 
applicable interval specified in paragraph (j) or (k) of this AD.
    (1) Within 100 flight cycles following an electronic centralized 
aircraft monitoring (ECAM) caution ``L/G SHOCK ABSORBER FAULT'' 
associated with at least one of the following centralized fault 
display system (CFDS) messages specified in paragraph (i)(1)(i), 
(i)(1)(ii), or (i)(1)(iii) of this AD.
    (i) ``N L/G EXT PROX SNSR 24GA TGT POS.''
    (ii) ``N L/G EXT PROX SNSR 25GA TGT POS.''
    (iii) ``N L/G SHOCK ABSORBER FAULT 2526GM.''
    (2) At the later of the times specified in paragraphs (i)(2)(i) 
and (i)(2)(ii) of this AD.
    (i) Within 20 months, 6,000 flight hours, or 4,500 flight cycles 
since the date of issuance of the original French standard 
airworthiness certificate, or French export certificate of 
airworthiness, whichever occurs first.
    (ii) Within 6 months, 1,800 flight hours, or 1,350 flight cycles 
after the effective date of this AD, whichever occurs first.

Repetitive Inspection Intervals

    (j) For airplanes not specified in paragraph (g) of this AD that 
are equipped with EMM BSCU standard L4.1 or L4.5: Repeat the 
inspection specified in paragraph (i) of this AD thereafter at 
intervals not to exceed the earliest of 6 months; 1,800 flight 
hours; 1,350

[[Page 16752]]

flight cycles; or 100 flight cycles following certain ECAM cautions 
and CFDS messages, as specified in paragraph (i)(1) of this AD.
    (k) For airplanes not specified in paragraph (g) of this AD that 
are equipped with EMM BSCU standard L4.8 or a non-EMM BSCU: Repeat 
the inspection specified in paragraph (i) of this AD thereafter at 
intervals not to exceed the earliest of 20 months; 6,000 flight 
hours; 4,500 flight cycles; or 100 flight cycles following certain 
ECAM cautions and CFDS messages, as specified in paragraph (i)(1) of 
this AD.

    Note 2: For the purposes of this AD, a special detailed 
inspection is: ``An intensive examination of a specific item, 
installation, or assembly to detect damage, failure, or 
irregularity. The examination is likely to make extensive use of 
specialized inspection techniques and/or equipment. Intricate 
cleaning and substantial access or disassembly procedure may be 
required.''

Optional Terminating Action

    (l) For airplanes that are not specified in paragraph (g) of 
this AD: Installation of an NLG with new upper support anti-rotation 
lugs and new cylinder lugs, or installation of an NLG that was never 
driven by EMM BSCU standard L4.1 and L4.5; combined with 
installation of an EMM BSCU standard L4.8 or a non-EMM BSCU; 
constitutes terminating action for the requirements of this AD. Do 
the installations in accordance with a method approved by either the 
Manager, International Branch, ANM-116; or the EASA (or its 
delegated agent). Chapter 32 of the Airbus A318/A319/A320/A321 
Aircraft Maintenance Manual (AMM) is one approved method for doing 
the installations.

No Report Required

    (m) Although Airbus Service Bulletin A320-32-1310, dated 
February 8, 2006, specifies sending certain inspection results to 
Airbus, this AD does not include that requirement.

Credit Paragraph

    (n) Inspections done before the effective date of this AD in 
accordance with Chapter 12, Subject 12-14-32 of the Airbus A318/
A319/A320/A321 AMM, as revised by Airbus A318/A319/A320/A321 AMM 
Temporary Revision 12-001, dated November 13, 2005, are acceptable 
for compliance with the requirements of paragraph (i) of this AD.

Alternative Methods of Compliance (AMOCs)

    (o)(1) The Manager, International Branch, ANM-116, has the 
authority to approve AMOCs for this AD, if requested in accordance 
with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Related Information

    (p) EASA airworthiness directive 2006-0174, dated June 21, 2006, 
also addresses the subject of this AD.

    Issued in Renton, Washington, on March 26, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-6343 Filed 4-4-07; 8:45 am]
BILLING CODE 4910-13-P