[Federal Register Volume 70, Number 238 (Tuesday, December 13, 2005)]
[Proposed Rules]
[Pages 73671-73674]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-23953]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-AD]
RIN 2120-AA64


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

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

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: The FAA is revising an earlier NPRM for an airworthiness 
directive (AD) that applies to certain Aerospatiale Model ATR42-200, -
300, and -320 airplanes. The original NPRM would have required doing 
repetitive inspections of the upper arms of the main landing gear (MLG) 
side braces for missing or inadequately bonded identification plates; 
replacing the upper arm if necessary; and replacing the side brace 
assembly with a modified part. The original NPRM resulted from an 
operator who reported experiencing an unlock warning for the MLG on the 
right side of the airplane. This action revises the original NPRM by 
proposing to require doing an ultrasonic inspection of the upper arm of 
the MLG side brace for any defects and related investigative/corrective 
actions if necessary, instead of replacing the upper arm if necessary. 
This action also adds airplanes to the applicability. We are proposing 
this supplemental NPRM to prevent cracking of the upper arms of the 
side braces of the MLG, which could result in failure of the MLG during 
landing and possible damage to the airplane and injury to the 
flightcrew and passengers.

DATES: We must receive comments on this supplemental NPRM by January 9, 
2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this supplemental NPRM.
     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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 
03, France, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: Tom Rodriguez, Aerospace Engineer, 
International Branch, ANM-116, Transport Airplane Directorate, FAA, 
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 supplemental NPRM. Include the docket number 
``Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-AD'' at 
the beginning of your comments. We specifically invite comments on the 
overall regulatory, economic, environmental, and energy aspects of this 
supplemental NPRM. We will consider all comments received by the 
closing date and may amend this supplemental NPRM in light of those 
comments.
    We will post all comments submitted, 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 supplemental NPRM. 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 in the Nassif Building at the DOT 
street address stated in ADDRESSES. Comments will be available in the 
AD docket shortly after the Docket Management System receives them.

Discussion

    We proposed to amend 14 CFR part 39 with a notice of proposed 
rulemaking (NPRM) for an airworthiness directive (AD) (the ``original 
NPRM''). The original NPRM applies to certain Aerospatiale Model ATR42-
200, -300, and -320 airplanes. The original NPRM was published in the 
Federal Register on February 1, 2005 (70 FR 5081). The original NPRM 
proposed to require doing repetitive inspections of the upper arms of 
the main landing gear (MLG) side braces for missing or inadequately 
bonded identification plates; replacing the upper arm if necessary; and 
replacing the side brace assembly with a modified part.

Relevant Service Information

    Since the original NPRM was issued, Messier-Dowty has issued 
Special Inspection Service Bulletin 631-32-181, Revision 2, dated June 
3, 2005. (Messier-Dowty Special Inspection Service Bulletin 631-32-175, 
dated January 7, 2004, was referenced in the original NPRM as the 
appropriate source of service information for doing the repetitive 
inspections and replacements of the upper arms if necessary.) Revision 
2 of the service bulletin describes procedures for doing repetitive 
visual inspections of the upper arms of the MLG side brace assemblies 
for missing or partially unstuck identification plates and beads of 
glue. If any identification plate or bead of glue is missing or 
partially unstuck, the service bulletin also describes procedures for 
doing an ultrasonic inspection of the upper arm of the MLG side brace 
for any defects and doing related investigative and corrective actions 
if necessary. The related investigative action is a visual inspection 
of the MLG side brace surface for any paint tears, scratches, or 
corrosion prior to accomplishing the ultrasonic inspection. The 
corrective actions include the following:

[[Page 73672]]

     If any paint tear, scratch, or corrosion is found on the 
surface of the upper arm, removing the contamination prior to doing the 
ultrasonic inspection.
     If the echo is less than 20%, restoring the plate areas 
and reidentifying the identification plate.
     If the echo is 20% or greater, replacing the MLG side 
brace with an MLG side brace equipped with an airworthy upper arm.
    Accomplishing the actions specified in Messier-Dowty Special 
Inspection Service Bulletin 631-32-181, Revision 2, and the 
replacements in Messier-Dowty Service Bulletin 631-32-176, Revision 1, 
dated June 2, 2004, is intended to adequately address the unsafe 
condition. (Messier-Dowty Service Bulletin 631-32-176, Revision 1, was 
referenced in the original NPRM as the appropriate source of service 
information for replacing a side brace assembly with a modified part.) 
The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, mandated the service information 
and issued French airworthiness directive F-2005-106, dated July 6, 
2005, to ensure the continued airworthiness of these airplanes in 
France. French airworthiness directive F-2005-106 supersedes French 
airworthiness directive F-2004-006, dated January 7, 2004, which was 
referenced as related information in paragraph (l) of the original 
NPRM. French airworthiness directive F-2005-106 also adds new airplanes 
to the applicability. We have revised the applicability of the 
supplemental NPRM to match French airworthiness directive F-2005-106.

Clarification Between the Supplemental NPRM and Service Bulletin

    Where Messier-Dowty Special Inspection Service Bulletin 631-32-181, 
Revision 2, specifies replacing a side brace with a side brace equipped 
with an airworthy upper arm, this supplemental NPRM proposes to replace 
it with a side brace equipped with an upper arm modified in accordance 
with Messier-Dowty Service Bulletin 631-32-176, Revision 1.

Clarification of Inspection Terminology

    The ``visual inspection'' specified in Revision 2 of Messier-Dowty 
Special Inspection Service Bulletin 631-32-181 is referred to as a 
``general visual inspection'' in this supplemental NPRM. We have 
included the definition for a general visual inspection in a note in 
the supplemental NPRM.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

    We have revised this supplemental NPRM to clarify the appropriate 
procedure for notifying the principal inspector before using any 
approved AMOC on any airplane to which the AMOC applies.

Comments

    We have considered the following comments on the original NPRM.

Request to Use AMOC

    One commenter requests that we revise the original NPRM to allow 
operators a means for mitigating any corrosion and reidentifying the 
upper arms of the MLG side braces, rather than proposing to require 
replacement of the upper arms. The commenter suggests that a 
combination of blending, coating, and a part identification method such 
as electro-etching would be a more appropriate solution to address the 
unsafe condition of the original NPRM. The commenter states that 
electro-etching would have minimal structural impact on the upper arms, 
while providing a permanent mark that can only be removed by grinding.
    We partially agree. As stated previously, if any identification 
plate or bead of glue is missing or partially unstuck, this 
supplemental NPRM proposes to require doing an ultrasonic inspection of 
the upper arm of an MLG side brace for any defects (and doing related 
investigative and corrective actions if necessary), rather than 
proposing to replace the upper arm. Although, depending on the results 
of the ultrasonic inspection, operators may be required to replace the 
side brace assembly with a part modified in accordance with Messier-
Dowty Service Bulletin 631-32-176, Revision 1. This supplemental NPRM 
also proposes to require modification of the side brace assemblies to 
terminate the repetitive visual inspections. However, under the 
provisions of paragraph (m) of the proposed final rule, we may consider 
requests for approval of an AMOC if sufficient data are submitted to 
substantiate that such a design change would provide an acceptable 
level of safety.

Request to Withdraw NPRM

    The same commenter believes that the original NPRM is an 
overreaction to a single event, the cause of which can still be 
speculated upon. The commenter also believes that any potential unsafe 
condition can be addressed by other means. We infer the commenter 
requests that we withdraw the original NPRM.
    We do not agree. Although the original NPRM was prompted by one 
report, we have identified an unsafe condition that is likely to exist 
or develop on other products of the same type design. The affected 
identification plates are located in a high stress area where they 
could be torn down. When an identification plate is torn down, the 
protective treatment on the upper arm of the MLG side brace could be 
damaged or stripped. Damaged or stripped protective treatment could 
lead to corrosion and consequent cracking of the upper arms of the MLG 
side braces. We have also considered the action taken by the authority 
of the state of design and the manufacturer's recommendation. Cracking 
of the upper arms of the side braces of the MLG, if not corrected, 
could result in failure of the MLG during landing and possible damage 
to the airplane and injury to the flightcrew and passengers.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

    The changes discussed above expand the scope of the original NPRM; 
therefore, we have determined that it is necessary to reopen the 
comment period to provide additional opportunity for public comment on 
this supplemental NPRM.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this supplemental NPRM.

                                                                     Estimated Costs
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                                                                                                                 Number of U.S.-
                Action                        Work hours          Average labor       Parts         Cost per       registered           Fleet cost
                                                                  rate per hour                     airplane        airplanes
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General visual inspection, per         1.......................             $65            None             $65              54  $3,510, per inspection
 inspection cycle.                                                                                                                cycle.

[[Page 73673]]

 
Replacement of side brace assemblies.  2 (1 hour per side                    65              $0             130              54  7,020
                                        brace).
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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 
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 supplemental NPRM 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 
adding the following new airworthiness directive (AD):

Aerospatiale: Docket No. FAA-2005-20220; Directorate Identifier 
2004-NM-152-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
9, 2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Aerospatiale Model ATR42-200, -300, and -
320 airplanes, certificated in any category; with main landing gear 
(MLG) side brace assemblies having part number (P/N) D22710000-( ) 
except -8, equipped with upper arms having P/N D56778-10.

Unsafe Condition

    (d) This AD results from an operator who reported experiencing 
an unlock warning for the MLG on the right side of the airplane. We 
are issuing this AD to prevent cracking of the upper arms of the 
side braces of the MLG, which could result in failure of the MLG 
during landing and possible damage to the airplane and 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.

Service Bulletin References

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of the following service bulletins, as 
applicable:
    (1) For the general visual inspection and ultrasonic inspection 
specified in paragraphs (g) and (h) of this AD, respectively: 
Messier-Dowty Special Inspection Service Bulletin 631-32-181, 
Revision 2, dated June 3, 2005; and
    (2) For the replacement specified in paragraph (j) of this AD: 
Messier-Dowty Service Bulletin 631-32-176, Revision 1, dated June 2, 
2004.

Repetitive Inspections of Identification Plates

    (g) Within 2 months or 500 flight hours after the effective date 
of this AD, whichever is first: Do a general visual inspection of 
the upper arms of the MLG side braces for inadequately bonded 
identification plates having P/Ns D61565-1, D61566-1, D61567-1, and 
D61568-1 and for any missing bead of glue, in accordance with the 
service bulletin. Thereafter at intervals not to exceed 2 months or 
500 flight hours, whichever is first: Repeat the inspection of the 
upper arm of the MLG side brace for any side brace assembly that has 
not been inspected in accordance with paragraph (h) of this AD or 
replaced as required by paragraph (j) 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 
ensure visual access to all 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.''

Ultrasonic Inspection, if Necessary

    (h) If any identification plate having P/N D61565-1, D61566-1, 
D61567-1, or D61568-1 or any bead of glue is missing or found 
inadequately bonded during any inspection required by paragraph (g) 
of this AD: Within 25 flight hours since the most recent general 
visual inspection, do an ultrasonic inspection of the upper arm of 
the MLG side brace for any defects and do any related investigative 
and corrective actions as applicable, by doing all of the applicable 
actions specified in Part B.(3) of the service bulletin; except 
where the service bulletin specifies replacing the side brace with a 
side brace equipped with an airworthy upper arm, replace it with a 
part modified in accordance with paragraph (j) of this AD. Any 
corrective actions must be done before further flight after doing 
the ultrasonic inspection.

[[Page 73674]]

Additional Ultrasonic Inspection for Certain Airplanes

    (i) For airplanes on which the ultrasonic inspection specified 
in paragraph (h) of this AD has been accomplished in accordance with 
Messier-Dowty Special Inspection Service Bulletin 631-32-181, 
Revision 1, dated March 16, 2005: Within 25 flight hours after the 
effective date of the AD, do all the applicable actions specified in 
paragraph (h) of this AD, in accordance with Messier-Dowty Special 
Inspection Service Bulletin 631-32-181, Revision 2, dated June 3, 
2005.

Replacement with a Modified Side Brace Assembly

    (j) At the applicable compliance time specified in paragraphs 
(j)(1) or (j)(2) of this AD: Remove the side brace assembly and 
replace it with a part modified by doing all of the actions in the 
service bulletin. Replacement of a side brace assembly with a 
modified part terminates the repetitive inspections required by 
paragraph (g) of this AD for that modified side brace assembly only. 
If the side brace assembly of the left and right MLG is replaced 
with a modified part, no more work is required by paragraph (g) of 
this AD.
    (1) For airplanes on which Messier-Dowty Service Bulletin 631-
32-072 has not been accomplished: Before the accumulation of 15,000 
total flight cycles on a side brace assembly since new or since last 
overhaul, or 96 months on a side brace assembly since new or since 
last overhaul, whichever is first.
    (2) For airplanes on which Messier-Dowty Service Bulletin 631-
32-072 has been accomplished: Before the accumulation of 18,000 
total flight cycles on a side brace assembly since new or since last 
overhaul, or 96 months on a side brace assembly since new or since 
last overhaul, whichever is first.

Credit for Previous Service Bulletin

    (k) Replacements done before the effective date of this AD in 
accordance with Messier-Dowty Service Bulletin 631-32-176, dated 
February 26, 2004, are acceptable for compliance with the 
corresponding requirements of paragraph (j) of this AD.

No Reporting Requirement

    (l) Although Messier-Dowty Special Inspection Service Bulletin 
631-32-181, Revision 2, dated June 3, 2005, specifies to submit 
certain information to the manufacturer, this AD does not include 
that requirement.

Alternative Methods of Compliance (AMOCs)

    (m)(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) Before using any AMOC approved in accordance with 14 CFR 
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

    (n) French airworthiness directive F-2005-106, dated July 6, 
2005, also addresses the subject of this AD.

    Issued in Renton, Washington, on December 6, 2005.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-23953 Filed 12-12-05; 8:45 am]
BILLING CODE 4910-13-P