[Federal Register Volume 65, Number 229 (Tuesday, November 28, 2000)]
[Proposed Rules]
[Pages 70815-70819]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-30122]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-139-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to all Aerospatiale Model 
ATR42-300 and -320 series airplanes. The existing AD requires 
repetitive ultrasonic inspections to detect cracking of certain lugs on 
the main landing gear (MLG), replacement of cracked lugs with new or 
serviceable parts, and a follow-on inspection; and provides for an 
optional terminating action for the repetitive inspections. This action 
would remove that terminating action and require new repetitive 
inspections of the rubber sealant to detect shearing, and corrective 
action, if necessary. This action also would require new one-time 
visual and fluorescent penetrant inspections to detect discrepancies of 
certain lugs and refurbishment of the MLG barrel and swing lever 
assemblies, which would terminate the requirements of this proposed AD. 
This action would also revise the applicability of the existing AD. 
This proposal is prompted by issuance of mandatory continuing 
airworthiness information by a foreign civil airworthiness authority. 
The actions specified by the proposed AD are intended to detect and 
correct discrepancies of the MLG barrel lower lugs, which could result 
in reduced structural integrity and possible collapse of the MLG.

DATES: Comments must be received by December 28, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-139-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 
03, France. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this

[[Page 70816]]

proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-139-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-139-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On December 15, 1997, the FAA issued AD 97-26-19, amendment 39-
10262 (62 FR 66980, December 23, 1997), applicable to all Aerospatiale 
Model ATR42-300 and -320 series airplanes, to require repetitive 
ultrasonic inspections to detect fatigue cracks of the lower lugs of 
the barrel of the main landing gear (MLG); and replacement of cracked 
lower lugs with new or serviceable parts, and a follow-on inspection. 
The existing AD further provides for an optional terminating action for 
the repetitive inspections. That action was prompted by issuance of 
mandatory continuing airworthiness information by a foreign civil 
airworthiness authority. The requirements of that AD are intended to 
detect and correct fatigue cracking of the lower lugs of the barrel of 
the MLG, which could lead to collapse of the MLG.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the Direction Generale de l'Aviation 
Civile (DGAC), which is the airworthiness authority for France, has 
advised the FAA of cases of rotation of the MLG bushings at the 
swinging lever hinge. This rotation damaged the anticorrosion 
protection of the MLG barrel. These cases occurred on airplanes on 
which the optional terminating action provided in the existing AD had 
been accomplished. Corrosion of the MLG barrel, if not corrected, could 
result in reduced structural integrity and possible collapse of the 
MLG.

Explanation of Relevant Service Information

    Messier-Dowty (the manufacturer of landing gears installed on Model 
ATR42 series airplanes) has issued Service Bulletin 631-32-144, dated 
January 19, 1998, which describes procedures for repetitive visual 
inspections of the rubber sealant around the bushings at the MLG barrel 
and swinging lever hinge point to detect discrepancies (including 
shearing or separation). Corrective actions for discrepancies include 
repeating the actions (including an ultrasonic inspection to detect 
fatigue cracks of the lower lugs of the MLG barrel, and, if necessary, 
replacement of the MLG barrel assembly with a new or serviceable MLG 
barrel assembly) specified by Messier-Dowty Service Bulletin 631-32-
132, dated January 21, 1997.
    Messier-Dowty has also issued Service Bulletin 631-32-145, dated 
February 16, 1998, which describes procedures for one-time detailed 
visual and fluorescent penetrant inspections of the MLG barrel lower 
lugs; and refurbishment of the barrel lower lug and swinging lever 
assemblies, including restoration of the protective coating, 
replacement of the old bushings with new bushings, and installation of 
lubrication fittings. This service bulletin replaces Messier-Dowty 
Service Bulletin 631-32-133 (which the existing AD refers to for 
accomplishment of the optional terminating action).
    Accomplishment of the actions specified by the service bulletins is 
intended to adequately address the identified unsafe condition. The 
DGAC classified these service bulletins as mandatory and issued French 
airworthiness directive 1996-294(B) R4, dated March 10, 1999, in order 
to ensure the continued airworthiness of these airplanes in France.

FAA's Conclusions

    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. Pursuant to this 
bilateral airworthiness agreement, the DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, reviewed all available information, and determined that AD 
action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would supersede AD 97-26-19 to:
     Continue to require repetitive ultrasonic inspections to 
detect fatigue cracks of the lower lugs of the MLG barrel, replacement 
of cracked lower lugs with new or serviceable parts, and a follow-on 
inspection;
     Require new one-time visual and fluorescent penetrant 
inspections to detect discrepancies of certain lugs, and refurbishment 
of the MLG barrel and swing lever assemblies; which would terminate the 
repetitive inspections;
     Reduce the repetitive interval for the ultrasonic 
inspection for certain airplanes;
     Revise the applicability to include Model ATR42-200 series 
airplanes, which have been determined to be subject to the identified 
unsafe condition;
     Revise the applicability to exclude airplanes that have 
been refurbished in accordance with Messier-Dowty Service Bulletin 631-
32-145; and
     Require operators to report results of inspection findings 
to Messier-Dowty.
    The actions would be required to be accomplished in accordance with 
the service bulletins described previously, except as discussed below.

Differences Between Proposed AD and French Airworthiness Directive

    The proposed AD would require an inspection of the rubber sealant 
around the bushings at the MLG barrel and swinging lever point within 
400 flight hours; the parallel French airworthiness directive 
recommends accomplishment of the inspection prior to the next ``A'' 
check. In developing an appropriate compliance time for this proposed 
AD, the FAA considered the minimum maintenance intervals recommended by 
the Maintenance Review Board, the DGAC's recommendation, the degree of 
urgency associated with addressing the subject unsafe condition, and 
the average utilization of the affected fleet. Further, because 
maintenance schedules, including ``A'' checks, may vary from operator 
to operator, there would be no assurance that the actions would be 
accomplished within the proposed compliance time. In light of these 
factors, the FAA finds that the compliance time of 400 flight hours, as 
proposed, represents the maximum interval of time allowable for the 
affected airplanes to continue to operate prior to accomplishing the 
proposed actions without compromising safety.
    Operators should note that, unlike the procedures described in 
Messier-Dowty Service Bulletin 631-32-144, this proposed AD would not 
permit further flight with discrepant sealant. The FAA has determined 
that, because of the safety implications and consequences

[[Page 70817]]

associated with such discrepancies, any subject sealant that is found 
to be discrepant must be repaired or modified prior to further flight.
    Operators should note that, although Messier-Dowty Service Bulletin 
631-32-145 specifies that the manufacturer may be contacted for 
disposition of certain repair conditions, this proposal would require 
either replacing the discrepant MLG barrel, or repairing the discrepant 
part in accordance with a method approved by the FAA or the DGAC (or 
its delegated agent). In light of the type of repair that would be 
required to address the identified unsafe condition, and in consonance 
with existing bilateral airworthiness agreements, the FAA has 
determined that, for this proposed AD, a repair approved by either the 
FAA or the DGAC would be acceptable for compliance with this proposed 
AD.

Cost Impact

    There are approximately 84 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspection that is currently required by AD 97-26-19, and 
retained in this proposed AD, takes approximately 2 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the currently required 
actions on U.S. operators is estimated to be $120 per airplane, per 
inspection cycle.
    The new inspections and refurbishment that are proposed in this AD 
action would take approximately 29 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Required 
parts would cost approximately $4,822 per airplane. Based on these 
figures, the cost impact of the proposed requirements of this AD on 
U.S. operators is estimated to be $551,208, or $6,562 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by removing amendment 39-10262 (62 FR 
66980, December 23, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

Aerospatiale: Docket 98-NM-139-AD. Supersedes AD 97-26-19, Amendment 
39-10262.
    Applicability: Model ATR42-200, -300, and -320 series airplanes; 
certificated in any category; except airplanes that have been 
refurbished in accordance with Messier-Dowty Service Bulletin 631-
32-145, dated February 16, 1998.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (k)(1) 
of this AD. The request should include an assessment of the effect 
of the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct discrepancies of the main landing gear 
(MLG) barrel lower lugs, which could result in reduced structural 
integrity and possible collapse of the MLG, accomplish the 
following:

Ultrasonic Inspection

    (a) For airplanes on which the actions specified by Messier-
Dowty Service Bulletin 631-32-133, dated February 24, 1997, as 
revised by Change Notice No. 1, dated March 18, 1997, have not been 
accomplished prior to the effective date of this AD: Perform an 
ultrasonic inspection to detect fatigue cracks of the lower lugs of 
the barrel of the MLG, in accordance with Messier-Dowty Service 
Bulletin 631-32-132, dated January 21, 1997, at the applicable time 
specified in paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD.
    (1) For Model ATR42-300 and -320 series airplanes: Inspect 
within 2 years after the last overhaul or repair of the lower lugs 
of the barrel of the MLG; or within 60 days after March 7, 1997 (the 
effective date of AD 97-04-09, amendment 39-9933); whichever occurs 
later.
    (2) For Model ATR42-300 and -320 series airplanes: Inspect 
within 5 years after the installation of a new MLG barrel assembly, 
or within 60 days after January 7, 1998 (the effective date of AD 
97-26-19, amendment 39-10262); whichever occurs later.
    (3) For Model ATR42-200 series airplanes: Inspect within 2 years 
after the last overhaul or repair of the lower lugs of the barrel of 
the MLG, or within 60 days after the effective date of this AD, 
whichever occurs later.
    (4) For Model ATR42-200 series airplanes: Inspect within 5 years 
after the installation of a new MLG barrel assembly, or within 60 
days after the effective date of this AD, whichever occurs later.
    (b) If, during any inspection specified in paragraph (a) of this 
AD, no ultrasonic echo (as described in Messier-Dowty Service 
Bulletin 631-32-133, dated February 24, 1997, as revised by Change 
Notice No. 1, dated March 18, 1997) is detected, or if the echo is 
less than 20%: Except as required by paragraph (c) of this AD, 
repeat the ultrasonic inspection thereafter at intervals not to 
exceed 900 landings.
    (c) For airplanes that are subject to the repetitive inspection 
requirements of paragraph (b) of this AD: As of the effective date 
of this AD, repeat the inspection, as specified by Table 1 of this 
AD, until the requirements of paragraph (f) of this AD are 
accomplished. Table 1 is as follows:

[[Page 70818]]



                      Table 1.--Repetitive Interval
------------------------------------------------------------------------
   If the first ultrasonic inspection
 specified by paragraph (a) of this AD      Then repeat the ultrasonic
             was done . . .                      inspection . . .
------------------------------------------------------------------------
(1) At least 24 months, and less than    Within 500 landings after the
 42 months, before the effective date     first ultrasonic inspection,
 of this AD.                              or within 60 days after the
                                          effective date of this AD,
                                          whichever occurs later; and
                                          thereafter at intervals not to
                                          exceed 500 landings.
(2) Less than 24 months before the       At intervals not to exceed 900
 effective date of this AD, or at any     landings, for a period not to
 time on or after the effective date of   exceed 24 months after the
 this AD.                                 first ultrasonic inspection of
                                          (a) of this AD; and thereafter
                                          at intervals not to exceed 500
                                          landings.
------------------------------------------------------------------------

    (d) If, during any inspection specified in paragraph (a) of this 
AD, the echo is greater than or equal to 20%: Prior to further 
flight, replace the MLG barrel assembly with a new or serviceable 
MLG barrel assembly, in accordance with Messier-Dowty Service 
Bulletin 631-32-132, dated January 21, 1997.
    (1) If the damaged barrel assembly is replaced with an 
overhauled or repaired assembly, within 2 years after installation 
of that overhauled or repaired part, accomplish the actions 
specified in paragraph (a) of this AD.
    (2) If the damaged barrel assembly is replaced with a new barrel 
assembly, within 5 years after installation of that new part, 
accomplish the actions specified in paragraph (a) of this AD.

Inspection of Sealant

    (e) For airplanes on which the actions specified by Messier-
Dowty Service
    Bulletin 631-32-133, dated February 24, 1997, as revised by 
Change Notice No. 1, dated March 18, 1997, have been accomplished 
prior to the effective date of this AD: Within 400 flight hours 
after the effective date of this AD, perform a detailed visual 
inspection to detect discrepancies (including shearing or 
separation) of the rubber sealant between the bushings and the MLG 
barrel lower lugs, and between the bushing and the swinging lever 
lug, in accordance with Messier-Dowty Service Bulletin 631-32-144, 
dated January 19, 1998. Repeat the inspection thereafter at 
intervals not to exceed 400 flight hours, until accomplishment of 
the actions required by paragraph (f) of this AD.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) If no discrepancy is detected, repeat the detailed visual 
inspection specified in paragraph (e) of this AD thereafter at 
intervals not to exceed 300 landings, until accomplishment of the 
actions required by paragraph (f) of this AD.
    (2) If any discrepancy is detected, prior to further flight, 
repeat the ultrasonic inspection and all applicable corrective 
actions specified by paragraphs (a), (b), and (d) of this AD.

Inspections and MLG Refurbishment

    (f) For all airplanes: At the applicable time specified by 
paragraph (g) or (h) of this AD, accomplish the actions required by 
paragraphs (f)(1) and (f)(2) of this AD, in accordance with Messier-
Dowty Service Bulletin 631-32-145, dated February 16, 1998, or 
Revision 1, dated May 31, 1999. Accomplishment of the inspections 
and refurbishment required by this paragraph constitutes terminating 
action for the requirements of this AD.
    (1) Perform a one-time detailed visual inspection and a one-time 
fluorescent penetrant inspection to detect discrepancies (cracks, 
corrosion, and material defects) of the barrel lower lugs (outboard 
and inboard).
    (i) If no discrepancy is found, prior to further flight, 
refurbish the lugs in accordance with the service bulletin.
    (ii) If any discrepancy is found, prior to further flight, 
refurbish the lugs in accordance with the service bulletin and 
repeat the detailed visual inspection and fluorescent penetrant 
inspection. If any discrepancy remains, prior to further flight, do 
the actions specified by either paragraph (f)(1)(ii)(A) or 
(f)(1)(ii)(B) of this AD.
    (A) Replace the damaged MLG barrel with a new or reconditioned 
barrel.
    (B) Repair in accordance with a method approved by either the 
Manager, International Branch, ANM-116, FAA, Transport Airplane 
Directorate; or the Direction Generale de l'Aviation Civile (DGAC) 
(or its delegated agent). For a repair method to be approved by the 
Manager, International Branch, ANM-116, as required by this 
paragraph, the Manager's approval letter must specifically reference 
this AD.
    (2) Refurbish the MLG (including restoring the protective 
treatments, installing new bushings, and installing new lubrication 
points of the MLG barrel and swinging lever assemblies).

Compliance Times for Inspections and Refurbishment

    (g) For airplanes on which the actions specified by Messier-
Dowty Service Bulletin 631-32-133, dated February 24, 1997, have not 
been accomplished prior to the effective date of this AD: Do the 
actions required by paragraph (f) of this AD at the earlier of the 
times specified by paragraphs (g)(1) and (g)(2) of this AD.
    (1) At the next overhaul of the MLG leg, not to exceed 42 months 
after the effective date of this AD.
    (2) Within 42 months after the first ultrasonic inspection in 
accordance with paragraph (a) of this AD, or within 60 days after 
the effective date of this AD, whichever occurs later.
    (h) For airplanes on which the actions specified by Messier-
Dowty Service Bulletin 631-32-133, dated February 24, 1997, have 
been accomplished prior the effective date of this AD: Do the 
actions required by paragraph (f) of this AD within 24 months after 
the initial sealant inspection required by paragraph (e) of this AD.

Reporting Requirement

    (i) At the applicable time specified by paragraph (i)(1) or 
(i)(2) of this AD, submit a report of the results (both positive and 
negative findings) of the initial inspections required by paragraphs 
(a) and (e) of this AD to Messier-Dowty, BP 10-78142 Velizy Cedex, 
France. Information collection requirements contained in this 
regulation have been approved by the Office of Management and Budget 
(OMB) under the provisions of the Paperwork Reduction Act of 1980 
(44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 
2120-0056.
    (1) For airplanes on which the inspections are accomplished 
after the effective date of this AD: Submit a report of each 
inspection within 10 days after performing the applicable 
inspection.
    (2) For airplanes on which the inspections have been 
accomplished prior to the effective date of this AD: Submit the 
report within 10 days after the effective date of this AD.

Spares

    (j) As of the effective date of this AD, no person shall install 
a bushing, part number D66349, on the MLG barrel and swinging lever 
assemblies on any airplane.

Alternative Methods of Compliance

    (k)(1) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, International Branch, ANM-116. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, International Branch, ANM-114.
    (2) Alternative methods of compliance approved previously in 
accordance with AD 97-26-19, amendment 39-10262, are approved as 
alternative methods of compliance with this AD.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.


[[Page 70819]]



Special Flight Permits

    (l) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Note 4: The subject of this AD is addressed in French 
airworthiness directive 1996-294(B) R4, dated March 10, 1999.


    Issued in Renton, Washington, on November 20, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-30122 Filed 11-27-00; 8:45 am]
BILLING CODE 4910-13-U