[Federal Register Volume 60, Number 96 (Thursday, May 18, 1995)]
[Proposed Rules]
[Pages 26700-26702]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12208]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-18-AD]


Airworthiness Directives; Bombardier Model CL-600-1A11 (CL-600), 
CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A and -3R), and CL-600-2B19 
(Regional Jet Series 100) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Bombardier Model 
CL-600-1A11, CL-600-2A12, CL-600-2B16, and CL-600-2B19 series 
airplanes, that currently requires an inspection to detect cracking in 
the rudder control quadrant; replacement of any cracked quadrant with a 
new assembly; and retorquing of the castellated nut, as necessary. This 
action would require a follow-on inspection of certain rudder control 
quadrants to detect cracks that start at the inside root radius of the 
spigot; modification of any cracked quadrant; and eventual modification 
of certain quadrants. This action also would add airplanes to the 
applicability of the existing AD. This proposal is prompted by the 
development of a modification, which, when installed, will positively 
address the identified unsafe condition. The actions specified by the 
proposed AD are intended to prevent loss of rudder control due to 
stress corrosion of the rudder control quadrant.

DATES: Comments must be received by June 19, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-18-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 Canadair, Aerospace Group, P.O. Box 6087, Station Centre-
ville, Quebec H3C 3G9, Canada. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Engine and Propeller Directorate, New York 
Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley 
Stream, New York.

FOR FURTHER INFORMATION CONTACT: Franco Pieri, Aerospace Engineer, 
Airframe Branch, ANE-172, FAA, Engine and Propeller Directorate, New 
York Aircraft Certification Office, 10 Fifth Street, Third Floor, 
Valley Stream, New York 11581; telephone (516) 256-7526; fax (516) 568-
2716.

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 notice 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 proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-18-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-103, Attention: Rules 
Docket No. 95-NM-18-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On November 1, 1993, the FAA issued AD 93-22-04, amendment 39-8729 
(58 FR 59161, November 8, 1993), which is applicable to certain 
Bombardier Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL-600-
2B16 (CL-601-3A and -3R), and CL-600-2B19 (Regional Jet Series 100) 
series airplanes. That AD requires a one-time ultrasonic or fluorescent 
penetrant inspection to detect cracking in the rudder control quadrant; 
replacement of any cracked quadrant with a new assembly; and retorquing 
of the castellated nut, as necessary. That action was prompted by a 
report of an in-flight failure of a rudder control quadrant, which 
resulted from stress corrosion. The requirements of that AD are 
intended to prevent loss of rudder control.
    In the preamble to AD 93-22-04, the FAA indicated that it 
considered that AD to be interim action, and that further rulemaking 
action would be considered once final action was identified. Bombardier 
has now developed a modification that will positively address the 
unsafe condition described in the AD by providing better resistance of 
the rudder quadrant against stress corrosion.
    Bombardier has issued the following service bulletins, which 
describe procedures for a one-time ultrasonic inspection of certain 
rudder control quadrants to detect cracks that start at the inside root 
radius of the spigot, and modification of any cracked quadrant.
    1. Canadair Challenger Service Bulletin No. 600-0637, Revision 1, 
dated November 15, 1994 (for Model CL-600-1A11 series airplanes);
    2. Canadair Challenger Service Bulletin No. 601-0426, Revision 1, 
dated November 15, 1994 (for Model CL-600-2A12 and -2B16 series 
airplanes); and [[Page 26701]] 
    3. Canadair Regional Jet Alert Service Bulletin S.B. A601R-27-011, 
Revision `A,' dated September 21, 1993, as revised by Notice of 
Revision A601R-27-011A-1, dated October 6, 1993, or Notice of Revision 
A601R-27-011A-2, dated June 14, 1994 (for Model CL-600-2B19 series 
airplanes).
    The first two service bulletins also describe procedures for 
eventual modification of certain rudder control quadrants. (Bombardier 
issued Canadair Service Bulletin S.B. 601R-27-015, Revision `A,' dated 
October 31, 1994, to specify these procedures for Model CL-600-2B19 
series airplanes.) The modification involves removal and disassembly of 
the quadrant assembly and installation of a modified quadrant assembly.
    Transport Canada Aviation, which is the airworthiness authority for 
Canada, classified these service bulletins as mandatory and issued 
Canadian airworthiness directive CF-94-23, dated December 1, 1994, in 
order to assure the continued airworthiness of these airplanes in 
Canada.
    These airplane models are manufactured in Canada and are type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, Transport Canada Aviation has kept 
the FAA informed of the situation described above. The FAA has examined 
the findings of Transport Canada Aviation, 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.
    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 93-22-04. It 
would no longer require the inspections currently specified in that AD, 
but would require instead a one-time ultrasonic inspection of certain 
rudder control quadrants to detect cracks that start at the inside root 
radius of the spigot; modification of any cracked quadrant; and 
eventual modification of certain quadrants. These actions would be 
required to be accomplished in accordance with the service bulletins 
described previously.
    This proposed AD also would expand the applicability of the 
existing rule to include additional airplanes that have been identified 
as subject to the addressed unsafe condition.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement.
    The FAA estimates that 212 airplanes of U.S. registry would be 
affected by this proposed AD.
    Accomplishment of the proposed inspection would take approximately 
4 work hours per airplane, at an average labor rate of $60 per work 
hour. Based on these figures, the total cost impact of the proposed 
inspection action on U.S. operators is estimated to be $50,880, or $240 
per airplane.
    Accomplishment of the proposed modification would take 
approximately 20 work hours per airplane, at an average labor rate of 
$60 per work hour. Required parts would be provided by the manufacturer 
at no cost to operators. Based on these figures, the total cost impact 
of the proposed modification action on U.S. operators is estimated to 
be $254,400, or $1,200 per airplane.
    Based on the figures discussed above, the total cost impact of this 
proposed rule on U.S. operators is estimated to be $305,280. This total 
cost impact figure is based on assumptions that no operator has yet 
accomplished any of the proposed requirements of this AD action, and 
that no operator would accomplish those actions in the future if this 
AD were not adopted.
    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-8729 (58 FR 
59161, November 8, 1993), and by adding a new airworthiness directive 
(AD), to read as follows:

    Bombardier, Inc. (Formerly Canadair): Docket 95-NM-18-AD. 
Supersedes AD 93-22-04, Amendment 39-8729.

    Applicability: Model CL-600-1A11 (CL-600) series airplanes, 
serial numbers 1004 through 1085 inclusive; Model CL-600-2A12 (CL-
601) series airplanes, serial numbers 3001 through 3066 inclusive; 
Model CL-600-2B16 (CL-601-3A and -3R) series airplanes, serial 
numbers 5001 through 5147 inclusive; and CL-600-2B19 (Regional Jet 
Series 100) series airplanes, serial numbers 7003 through 7038 
inclusive; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
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 use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, 
[[Page 26702]] alteration, or repair remove any airplane from the 
applicability of this AD.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of rudder control, accomplish the following:
    (a) Within 45 days after the effective date of this AD, perform 
an ultrasonic inspection to detect cracks at the inside root radius 
of the spigot of the rudder quadrant, part number (P/N) 600-92614-1 
(original quadrant) or P/N 600-92614-3 (quadrant modified with 
undercut), in accordance with the procedures specified in Canadair 
Challenger Service Bulletin No. 600-0637, Revision 1, dated November 
15, 1994 (for Model CL-600-1A11 series airplanes); Canadair 
Challenger Service Bulletin No. 601-0426, Revision 1, dated November 
15, 1994 (for Model CL-600-2A12 and -2B16 series airplanes); or 
Canadair Regional Jet Alert Service Bulletin S.B. A601R-27-011, 
Revision `A,' dated September 21, 1993, as revised by Notice of 
Revision A601R-27-011A-1, dated October 6, 1993, and Notice of 
Revision A601R-27-011A-2, dated June 14, 1994 (for Model CL-600-2B19 
series airplanes); as applicable. A fluorescent penetrant inspection 
may be accomplished in lieu of the ultrasonic inspection provided 
that the rudder control quadrant assembly is removed prior to 
inspection. Accomplishment of the modification required by paragraph 
(b) of this AD eliminates the need for the inspection required by 
this paragraph, provided that the modification is accomplished 
within 45 days after the effective date of this AD.

    Note 2: Rudder quadrants having P/N's 600-92614-1 and -3 are 
part of the rudder quadrants having P/N's 600-92619-1 and -5, 
respectively.

    (1) If any crack is detected, prior to further flight, modify 
the rudder control quadrant in accordance with Canadair Service 
Bulletin No. 600-0637, Revision 1, dated November 15, 1994 (for 
Model CL-600-1A11 series airplanes); Canadair Service Bulletin No. 
601-0426, Revision 1, dated November 15, 1994 (for Model CL-600-2A12 
and -2B16 series airplanes); or Canadair Service Bulletin S.B. 
A601R-27-015, Revision `A,' dated October 31, 1994 (for Model CL-
600-2B19 series airplanes); as applicable.
    (2) If no crack is detected, no further action is required by 
paragraph (a) of this AD.
    (b) Within 6 months after the effective date of this AD, modify 
the rudder control quadrant, P/N 600-92619-1 or 600-92619-5, in 
accordance with Canadair Service Bulletin No. 600-0637, Revision 1, 
dated November 15, 1994 (for Model CL-600-1A11 series airplanes); 
Canadair Service Bulletin No. 601-0426, Revision 1, dated November 
15, 1994 (for Model CL-600-2A12 and -2B16 series airplanes); or 
Canadair Service Bulletin S.B. A601R-27-015, Revision `A,' dated 
October 31, 1994 (for Model CL-600-2B19 series airplanes); as 
applicable. Accomplishment of this modification eliminates the need 
for the inspection required by paragraph (a) of this AD.
    (c) 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, New York Aircraft Certification 
Office (ACO), FAA, Engine and Propeller Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, New York ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (d) 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.

    Issued in Renton, Washington, on May 12, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-12208 Filed 5-17-95; 8:45 am]
BILLING CODE 4910-13-U