
[Federal Register: June 10, 2008 (Volume 73, Number 112)]
[Proposed Rules]               
[Page 32659-32662]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10jn08-7]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0636; Directorate Identifier 2007-NM-324-AD]
RIN 2120-AA64

 
Airworthiness Directives; ATR Model ATR42-200, -300, and -320 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD results from mandatory 
continuing airworthiness information (MCAI) originated by an aviation 
authority of another country to identify and correct an unsafe 
condition on an aviation product. The MCAI describes the unsafe 
condition as:

    One ATR 42-300 experienced a collapse of the Right (RH) Main 
Landing Gear (MLG) when taxiing, caused by failure of the side brace 
assembly. Investigations revealed a crack propagation that occurred 
from a corrosion pit, in a very high stressed area of the upper arm. 
* * *
* * * * *

    The unsafe condition is cracking of the upper arms of the secondary 
side brace assemblies of the MLG, which could result in collapse of the 
MLG during takeoff or landing, damage to the airplane, and possible 
injury to the flightcrew and passengers. The proposed AD would require 
actions that are intended to address the unsafe condition described in 
the MCAI.

DATES: We must receive comments on this proposed AD by July 10, 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 W12-40, 1200 New 
Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office 
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 Operations 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: Tom Rodriguez, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
227-1137; 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-2008-0636; 
Directorate Identifier 2007-NM-324-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 based on 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

    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued EASA 
Airworthiness Directive 2007-0263, dated October 3, 2007 (referred to 
after this as ``the MCAI''), to correct an unsafe condition for the 
specified products. The MCAI states:

    ONE ATR 42-300 experienced a collapse of the Right (RH) Main 
Landing Gear (MLG) when taxiing, caused by failure of the side brace 
assembly. Investigations revealed a crack propagation that occurred 
from a corrosion pit, in a very high stressed area of the upper arm. 
Dimensions of the corrosion pit were lower than the minimum defect 
size that can be detected by usual inspection means used during 
landing gear overhaul. The superseded EASA (European Aviation Safety 
Agency) Airworthiness Directive (AD) 2007-0112 was issued to require 
repetitive inspections on affected high stressed areas on MLG side 
brace assemblies for crack detection and to replace the affected 
side brace assembly if any defect was found.
    Since the issuance of [EASA] AD 2007-0112, a modification of 
[the] side brace upper arm has been developed as terminating action. 
However, production non-conformity of the inspection tool was 
discovered.
    In order to correct the discrepancy of the initial tool, new 
inspection tool components have been manufactured and the Service 
Bulletin (SB) Messier Dowty 631-32-191 has been updated to revision 
2 accordingly. This directive mandates re-inspection of MLG side 
brace assemblies previously inspected in accordance with revision 1 
of the Messier Dowty SB 631-32-191 and reduces the inspection 
interval initially proposed in [EASA] AD 2007-0112 in order to 
maintain the same level of confidence.
* * * * *

The unsafe condition is cracking of the upper arms of the secondary 
side brace assemblies of the MLG, which could result in collapse of the 
MLG during takeoff or landing, damage to the airplane, and possible 
injury to the flightcrew and passengers. You may obtain further 
information by examining the MCAI in the AD docket.

Relevant Service Information

    Messier-Dowty has issued Special Inspection Service Bulletin 631-
32-191, Revision 2, dated August 30, 2007, and Service Bulletin 631-32-
194, dated June 6, 2007. ATR has issued Service Bulletin ATR42-32-0092, 
dated June 25, 2007. ATR has also issued Technical Instruction ATR42-
07-01, dated February 5, 2007. The actions described in this service 
information are intended to correct the unsafe condition identified in 
the MCAI.

FAA's Determination and Requirements of This Proposed AD

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with the State of Design Authority, we have 
been notified of the unsafe condition described in the MCAI and service 
information referenced above. We are proposing this AD because we 
evaluated all pertinent information and determined an unsafe condition 
exists and is likely to exist or develop on other products of the same 
type design.

[[Page 32660]]

Differences Between This AD and the MCAI or Service Information

    We have reviewed the MCAI and related service information and, in 
general, agree with their substance. But we might have found it 
necessary to use different words from those in the MCAI to ensure the 
AD is clear for U.S. operators and is enforceable. In making these 
changes, we do not intend to differ substantively from the information 
provided in the MCAI and related service information.
    We might also have proposed different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a NOTE within the proposed AD.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 31 products of U.S. registry. We also estimate that 
it would take about 35 work-hours per product to comply with the basic 
requirements of this proposed AD. The average labor rate is $80 per 
work-hour. Required parts would cost about $0 per product. Based on 
these figures, we estimate the cost of the proposed AD on U.S. 
operators to be $86,800, or $2,800 per product.

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 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 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. 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.

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 FAA amends Sec.  39.13 by adding the following new AD:

ATR--GIE Avions de Transport Regional (Formerly Aerospatiale): 
Docket No. FAA-2008-0636; Directorate Identifier 2007-NM-324-AD.

Comments Due Date

    (a) We must receive comments by July 10, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to ATR Model ATR42-200, -300, and -320 
airplanes, certificated in any category; excluding airplanes on 
which ATR Modification 8463 has been done.

Subject

    (d) Air Transport Association (ATA) of America Code 32: Landing 
gear.

Reason

    (e) The mandatory continuing airworthiness information (MCAI) 
states:
    One ATR 42-300 experienced a collapse of the Right (RH) Main 
Landing Gear (MLG) when taxiing, caused by failure of the side brace 
assembly. Investigations revealed a crack propagation that occurred 
from a corrosion pit, in a very high stressed area of the upper arm. 
Dimensions of the corrosion pit were lower than the minimum defect 
size that can be detected by usual inspection means used during 
landing gear overhaul. The superseded EASA (European Aviation Safety 
Agency) Airworthiness Directive (AD) 2007-0112 was issued to require 
repetitive inspections on affected high stressed areas on MLG side 
brace assemblies for crack detection and to replace the affected 
side brace assembly if any defect was found.
    Since the issuance of [EASA] AD 2007-0112, a modification of 
[the] side brace upper arm has been developed as terminating action. 
However, production non-conformity of the inspection tool was 
discovered.
    In order to correct the discrepancy of the initial tool, new 
inspection tool components have been manufactured and the Service 
Bulletin (SB) Messier Dowty 631-32-191 has been updated to revision 
2 accordingly. This directive mandates re-inspection of MLG side 
brace assemblies previously inspected in accordance with revision 1 
of the Messier Dowty SB 631-32-191 and reduces the inspection 
interval initially proposed in [EASA] AD 2007-0112 in order to 
maintain the same level of confidence.
* * * * *
    The unsafe condition is cracking of the upper arms of the 
secondary side brace assemblies of the MLG, which could result in 
collapse of the MLG during takeoff or landing, damage to the 
airplane, and possible injury to the flightcrew and passengers.

Actions and Compliance

    (f) For MLG side brace assemblies with part number (P/N) 
D22710000, without suffix ``-9'': Unless already done, do the 
following actions.
    (1) For airplanes on which the MLG side brace assemblies have 
not been inspected as of the effective date of this AD, in 
accordance with the Accomplishment Instructions of Messier-Dowty 
Service Bulletin 631-32-191, Revision 1, dated February 26, 2007: 
Perform the initial eddy current inspection for cracking of the MLG 
side brace, in accordance with the Accomplishment Instructions of 
Messier-Dowty Special Inspection Service Bulletin 631-32-191, 
Revision 2, dated August 30, 2007, at the applicable time specified 
in Table 1 of this AD. Unless otherwise specified, the flight cycles 
and times indicated in Table 1 of this AD must be interpreted as 
total flight cycles since overhaul, or time since overhaul, and as 
total flight cycles since new or time since manufacture for side 
brace assemblies that have not undergone any overhaul yet.

[[Page 32661]]



                       Table 1.--Compliance Times
------------------------------------------------------------------------
 For a MLG side brace assembly with the
 total flight cycles since new or total
 flight cycles since overhaul specified    Do the initial inspection at
 below as of the effective date of this     the time specified below--
                  AD--
------------------------------------------------------------------------
More than 8,000 flight cycles..........  Within 500 flight cycles after
                                          the effective date of this AD.
5,000 or more total flight cycles, but   Within 1,000 flight cycles
 not more than 8,000 total flight         after the effective date of
 cycles.                                  this AD or before accumulating
                                          8,500 flight cycles, whichever
                                          occurs first.
Less than 5,000 flight cycles..........  Within 2,000 flight cycles
                                          after the effective date of
                                          this AD or before accumulating
                                          6,000 flight cycles, whichever
                                          occurs first.
------------------------------------------------------------------------

    (2) For airplanes on which the MLG side brace assemblies have 
been inspected as of the effective date of this AD, in accordance 
with the Accomplishment Instructions of Messier-Dowty Service 
Bulletin 631-32-191, Revision 1, dated February 26, 2007: Within 
1,000 flight cycles after the last inspection or within 200 flight 
cycles after the effective date of this AD, whichever occurs later, 
perform an eddy current inspection for cracking of the MLG side 
brace, in accordance with the Accomplishment Instructions of 
Messier-Dowty Special Inspection Service Bulletin 631-32-191, 
Revision 2, dated August 30, 2007.
    (3) After accomplishment of the inspection required by paragraph 
(f)(1) or (f)(2) of this AD, repeat the inspection at intervals not 
to exceed 2,600 flight cycles in accordance with the Accomplishment 
Instructions of Messier-Dowty Special Inspection Service Bulletin 
631-32-191, Revision 2, dated August 30, 2007.
    (4) If any crack is found during any inspection required by 
paragraphs (f)(1), (f)(2) and (f)(3) of this AD, before further 
flight, replace the affected side brace in accordance with the 
Accomplishment Instructions of Messier-Dowty Special Inspection 
Service Bulletin 631-32-191, Revision 2, dated August 30, 2007.
    (5) At the applicable time specified in paragraph (f)(5)(i) or 
(f)(5)(ii) of this AD: Inspect for cracking, corrosion, and defects 
of the MLG side brace assemblies with P/N D22710000, without suffix 
``-9'', in accordance with the Accomplishment Instructions of 
Messier Dowty Service Bulletin 631-32-194, dated June 6, 2007.
    (i) For airplanes having side brace assemblies on which Messier-
Bugatti Service Bulletin 631-32-072 has not been incorporated: 
Before accumulating 16,000 total flight cycles or within 8 years 
after the effective date of this AD, whichever occurs first.
    (ii) For airplanes having side brace assemblies on which 
Messier-Bugatti Service Bulletin 631-32-072 has been incorporated: 
Before accumulating 19,000 total flight cycles or within 8 years 
after the effective date of this AD, whichever occurs first.
    (6) If no cracking, corrosion, or defect is found during any 
inspection required by paragraph (f)(5) of this AD, before further 
flight, modify and re-identify (by adding a suffix ``-9'' to P/N 
D22710000) the MLG side brace assemblies in accordance with the 
Accomplishment Instructions of ATR Service Bulletin ATR42-32-0092, 
dated June 25, 2007.
    (7) If any cracking, corrosion, or defect is found during any 
inspection required by paragraph (f)(5) of this AD, before further 
flight, replace the discrepant MLG side brace assembly with a 
modified and re-identified MLG side brace assembly in accordance 
with the Accomplishment Instructions of ATR Service Bulletin ATR42-
32-0092, dated June 25, 2007.

FAA AD Differences

    Note: This AD differs from the MCAI and/or service information 
as follows: Although the MCAI or service information allows further 
flight if a crack is found during compliance with the required 
inspections, this AD requires that you repair the crack before 
further flight.

Other FAA AD Provisions

    (g) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
International Branch, ANM-116, has the authority to approve AMOCs 
for this AD, if requested using the procedures found in 14 CFR 
39.19. Send information to ATTN: Tom Rodriguez, Aerospace Engineer, 
International Branch, ANM-116, Transport Airplane Directorate, FAA, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 227-1137; 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.
    (2) Airworthy Product: For any requirement in this AD to obtain 
corrective actions from a manufacturer or other source, use these 
actions if they are FAA-approved. Corrective actions are considered 
FAA-approved if they are approved by the State of Design Authority 
(or their delegated agent). You are required to assure the product 
is airworthy before it is returned to service.
    (3) Reporting Requirements: For any reporting requirement in 
this AD, under the provisions of the Paperwork Reduction Act, the 
Office of Management and Budget (OMB) has approved the information 
collection requirements and has assigned OMB Control Number 2120-
0056.

Related Information

    (h) Refer to MCAI EASA Airworthiness Directive 2007-0263, dated 
October 3, 2007, and the service information specified in Table 2 of 
this AD, for related information.

                                          Table 2.--Service Information
----------------------------------------------------------------------------------------------------------------
             Service Bulletin                        Revision                              Date
----------------------------------------------------------------------------------------------------------------
ATR Service Bulletin ATR 42-32-0092......  Original....................  June 25, 2007.
ATR Technical Instruction ATR 42 ATR 42-   Original....................  February 5, 2007.
 07-01.
Messier-Dowty Service Bulletin 631-32-194  Original....................  June 6, 2007.
Messier-Dowty Special Inspection Service   2...........................  August 30, 2007.
 Bulletin 631-32-191.
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[[Page 32662]]

    Issued in Renton, Washington, on June 3, 2008.
Michael J. Kaszycki,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-12934 Filed 6-9-08; 8:45 am]

BILLING CODE 4910-13-P
