[Federal Register Volume 70, Number 139 (Thursday, July 21, 2005)]
[Proposed Rules]
[Pages 42003-42005]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-14393]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 70, No. 139 / Thursday, July 21, 2005 / 
Proposed Rules  

[[Page 42003]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-21909; Directorate Identifier 2005-NM-059-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospatiale Model ATR72 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 adopt a new airworthiness directive (AD) 
for certain Aerospatiale Model ATR72 airplanes. This proposed AD would 
require a one-time general visual inspection for contamination of the 
surface of the upper arms of the main landing gear (MLG) secondary side 
brace assemblies; and repetitive eddy current inspections for cracking 
of the upper arms, and related specified and corrective actions if 
necessary. This proposed AD also would mandate eventual replacement of 
aluminum upper arms with steel upper arms, which would end the 
repetitive inspections. This proposed AD is prompted by two reports of 
rupture of the upper arm of the MLG secondary side brace due to fatigue 
cracking. We are proposing this AD to prevent 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.

DATES: We must receive comments on this proposed AD by August 22, 2005.

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.
     By 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.
    For service information identified in this proposed AD, contact 
Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, 
on the plaza level of the Nassif Building, Washington, DC. This docket 
number is FAA-2005-21909; the directorate identifier for this docket is 
2005-NM-059-AD.

FOR FURTHER INFORMATION CONTACT: Tom Rodriguez, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1137; 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 under ADDRESSES. Include ``Docket No. FAA-2005-21909; 
Directorate Identifier 2005-NM-059-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 submitted 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 our 
docket 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 can review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
can visit http://dms.dot.gov.

Examining the Docket

    You can 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 
(DMS) receives them.

Discussion

    The Direction G[eacute]n[eacute]rale de l'Aviation Civile (DGAC), 
which is the airworthiness authority for France, notified us that an 
unsafe condition may exist on certain Aerospatiale Model ATR72 
airplanes. The DGAC advises that there were two reports of rupture of 
the upper arm of the main landing gear (MLG) secondary side brace 
assembly. Fatigue cracking has been determined to be the cause of the 
ruptures. This cracking, if not corrected, could result in collapse of 
the MLG during takeoff or landing, damage to the airplane, and possible 
injury to the flightcrew and passengers.

Relevant Service Information

    Messier-Dowty has issued Special Inspection Service Bulletin 631-
32-178, Revision 1, dated September 30, 2004. The service bulletin 
describes procedures for, among other things, a one-time general visual 
inspection for contamination of the surface of the upper arms of the 
MLG secondary side brace assemblies, and an eddy current inspection for 
cracking of the upper arms. The service bulletin also recommends 
sending an inspection report to Messier-Dowty.
    Aerospatiale has issued Avions de Transport Regional Service 
Bulletin ATR72-32-1046, Revision 1, dated October 7, 2004. The service 
bulletin

[[Page 42004]]

contains no Accomplishment Instructions, but describes procedures for 
replacing the upper arms of the MLG secondary side brace assemblies. 
The service bulletin refers to Messier-Dowty Service Bulletin 631-32-
183, dated October 6, 2004, as the source of service information for 
accomplishing the replacement. Service Bulletin 631-32-183 describes 
procedures for replacing aluminum upper arms of the MLG secondary side 
brace assemblies with steel upper arms, and engraving a new suffix on 
the identification plate on the assembly.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition. The DGAC mandated 
the service information and issued French airworthiness directive F-
2004-164, dated October 13, 2004, to ensure the continued airworthiness 
of these airplanes in France.
    The French airworthiness directive refers to Messier-Bugatti 
Service Bulletin 631-32-085, dated August 21, 1992, as the source of 
service information for replacing the press-fitted ball cages of the 
lower and upper arms of the MLG secondary side brace assemblies with 
ball cages that are shrink-fitted and bonded with adhesive. For 
airplanes on which this replacement has been accomplished, the 
compliance time for the replacement of the aluminum upper arms is 
extended.

FAA's Determination and Requirements of the Proposed AD

    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. We have examined the DGAC's findings, 
evaluated all pertinent information, and determined that we need to 
issue an AD for products of this type design that are certificated for 
operation in the United States.
    Therefore, we are proposing this AD, which would require 
accomplishing the actions specified in Avions de Transport Regional 
Service Bulletin ATR72-32-1046, Revision 1; Messier-Dowty Special 
Inspection Service Bulletin 631-32-178, Revision 1; and Messier-Dowty 
Service Bulletin 631-32-183; described previously; except as discussed 
under ``Differences Between the Proposed AD and Messier-Dowty Special 
Inspection Service Bulletin 631-32-178.'' In addition, this proposed AD 
would require, for replacement of aluminum upper arms, an eddy current 
inspection and investigative or corrective actions. Replacement with 
steel arms would end the repetitive inspections, and replacement with 
aluminum arms would require repeating the eddy current inspections.

Differences Among Proposed AD, French Airworthiness Directive, and 
Messier-Dowty Service Information

    Although the French airworthiness directive requires replacing any 
defective upper arm of the MLG secondary side brace assemblies with a 
new or serviceable aluminum arm, or a new steel arm, there are no 
procedures specified in Service Bulletin 631-32-183 for replacing the 
defective arm with an aluminum arm. The service bulletin does reference 
the ATR Component Maintenance Manual (CMM), Chapter 32-18-41, Revision 
3, dated September 30, 2002, for procedures for replacing the affected 
arm with a new steel arm. Therefore, this proposed AD will reference 
the CMM for procedures for replacement of any defective aluminum upper 
arm with a new or serviceable aluminum upper arm. Chapter 32-18-41 
provides procedures for replacement of affected upper arms with either 
steel or aluminum upper arms. This difference has been coordinated with 
the DGAC.
    Special Inspection Service Bulletin 631-32-178, Revision 1, 
recommends sending an inspection report to Messier-Dowty, but this 
proposed AD does not contain that requirement.
    Special Inspection Service Bulletin 631-32-178, Revision 1, refers 
only to a ``visual inspection'' for contamination of the surface. We 
have determined that the procedures in the service bulletin should be 
described as a ``general visual inspection.'' A note has been included 
in this AD to define this type of inspection.

Costs of Compliance

    This proposed AD would affect about 18 airplanes of U.S. registry.
    The proposed initial and repetitive inspections would take about 1 
work hour per airplane, at an average labor rate of $65 per work hour. 
Based on these figures, the estimated cost of the proposed inspections 
for U.S. operators is $1,170, or $65 per airplane, per inspection 
cycle.
    The proposed replacement would take about 4 work hours per airplane 
(2 work hours per upper arm), at an average labor rate of $65 per work 
hour. Required parts would cost about $4,948 per airplane ($2,474 per 
upper arm). Based on these figures, the estimated cost of the proposed 
replacement for U.S. operators is $93,744, or $5,208 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. 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:

[[Page 42005]]

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 
airworthiness directive (AD):

Aerospatiale: Docket No. FAA-2005-21909; Directorate Identifier 
2005-NM-059-AD.

Comments Due Date

    (a) The Federal Aviation Administration must receive comments on 
this AD action by August 22, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Aerospatiale Model ATR72-101, -102, -201, 
-202, -211, -212, and -212A airplanes, certificated in any category; 
except airplanes that have received ATR Modification 5522 in 
production.

Unsafe Condition

    (d) This AD was prompted by two reports of rupture of the upper 
arm of the main landing gear (MLG) secondary side brace assembly due 
to fatigue cracking. We are issuing this AD to prevent 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.

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.

Inspections

    (f) At the latest of the times specified in paragraphs (f)(1), 
(f)(2), and (f)(3) of this AD: Accomplish a general visual 
inspection for contamination of the surface of the upper arms of the 
MLG secondary side brace assemblies, and an eddy current inspection 
for cracking of the upper arms by doing all the actions specified in 
Parts A and B of the Accomplishment Instructions of Messier-Dowty 
Special Inspection Service Bulletin 631-32-178, Revision 1, dated 
September 30, 2004. Repeat the eddy current inspection at intervals 
not to exceed 800 flight cycles until accomplishment of paragraph 
(h) of this AD.
    (1) Before the accumulation of 4,000 total flight cycles on the 
secondary side brace.
    (2) Before the accumulation of 800 flight cycles on the 
secondary side brace since overhauled.
    (3) Within 200 flight cycles after the effective date of this 
AD.

    Note 1: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
enhance visual access to all exposed surfaces in the inspection 
area. This level of inspection is made under normally available 
lighting conditions such as daylight, hangar lighting, flashlight, 
or droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

Related Specified and Corrective Actions

    (g) If any cracking is found during any inspection required by 
paragraph (f) of this AD: Before further flight, replace the 
affected upper arm of the MLG secondary side brace assembly as 
specified in paragraph (g)(1) or (g)(2) of this AD.
    (1) Replace the aluminum upper arm of the MLG secondary side 
brace assembly with a steel upper arm by doing the applicable 
actions specified in the Accomplishment Instructions of Messier-
Dowty Service Bulletin 631-32-183, dated October 6, 2004. This 
replacement ends the repetitive inspections required by paragraph 
(f) of this AD for that side brace only.
    (2) Replace the aluminum upper arm of the MLG secondary side 
brace assembly with a new or serviceable aluminum upper arm in 
accordance with a method approved by either the Manager, 
International Branch, ANM-116, Transport Airplane Directorate, FAA; 
or the Direction G[eacute]n[eacute]rale de l'Aviation Civile (or its 
delegated agent). ATR Component Maintenance Manual, Chapter 32-18-
41, Revision 3, dated September 30, 2002, is one approved method. 
Accomplish a general visual inspection for contamination of the 
surface of the upper arm before the accumulation of 4,000 total 
flight cycles on the upper arm, and if cracks are found, before 
further flight, replace the upper arm with a steel upper arm as 
required by paragraph (g)(1) of this AD. If no cracks are found, 
repeat the eddy current inspection thereafter at intervals not to 
exceed 800 flight cycles until accomplishment of paragraph (h) of 
this AD.

Terminating Action

    (h) Replace all aluminum upper arms of the MLG secondary side 
brace assembly with steel upper arms by doing all the applicable 
actions in accordance with the Accomplishment Instructions of 
Messier-Dowty Service Bulletin 631-32-183, dated October 6, 2004; at 
the applicable time specified in paragraph (h)(1), (h)(2), (h)(3), 
or (h)(4) of this AD. Accomplishing this replacement ends the 
repetitive inspections required by paragraph (f) of this AD.
    (1) For airplanes on which any upper arm has been overhauled 
before the effective date of this AD and on which Messier-Bugatti 
Service Bulletin 631-32-085, dated August 21, 1992, has not been 
accomplished, as of the effective date of this AD: Within 15,000 
flight cycles or 96 months, whichever is first, since overhaul on 
the affected upper arm.
    (2) For airplanes on which any upper arm has been overhauled 
before the effective date of this AD and on which Messier-Bugatti 
Service Bulletin 631-32-085, dated August 21, 1992, has been 
accomplished, as of the effective date of this AD: Within 18,000 
flight cycles or 96 months, whichever is first, since overhaul on 
the affected upper arm.
    (3) For airplanes on which any upper arm has not been overhauled 
and on which Messier-Bugatti Service Bulletin 631-32-085, dated 
August 21, 1992, has not been accomplished, as of the effective date 
of this AD: Before the accumulation of 15,000 total flight cycles on 
an upper arm since new, or within 96 months on an upper arm since 
new, whichever is first.
    (4) For airplanes on which any upper arm has not been overhauled 
and on which Messier-Bugatti Service Bulletin 631-32-085, dated 
August 21, 1992, has been accomplished, as of the effective date of 
this AD: Before the accumulation of 18,000 total flight cycles on an 
upper arm since new, or within 96 months on an upper arm since new, 
whichever is first.

No Report Required

    (i) Messier-Dowty Special Inspection Service Bulletin 631-32-
178, Revision 1, dated September 30, 2004, recommends sending an 
inspection report to Messier-Dowty, but this AD does not contain 
that requirement.

Parts Installation

    (j) As of the effective date of this AD, no person may install, 
on any airplane, an aluminum upper arm of the MLG secondary side 
brace assembly, unless the applicable requirements specified in 
paragraphs (f) and (g) of this AD have been accomplished.

Alternative Methods of Compliance (AMOCs)

    (k) The Manager, 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.

Related Information

    (l) French airworthiness directive F-2004-164, dated October 13, 
2004, also addresses the subject of this AD.

    Issued in Renton, Washington, on July 14, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-14393 Filed 7-20-05; 8:45 am]
BILLING CODE 4910-13-P