[Federal Register Volume 61, Number 131 (Monday, July 8, 1996)]
[Proposed Rules]
[Pages 35691-35693]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17218]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-247-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model 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 adoption of a new airworthiness 
directive (AD) that is applicable to certain Bombardier Model CL-600-
2B16 and CL-600-2B19 series airplanes. This proposal would require a 
one-time inspection of the spring bungee assembly of the nose landing 
gear (NLG) to ensure proper torque of the collar and correct clearance 
between the collar and the body of the bungee, and replacement of the 
spring bungee assembly with a serviceable unit, if necessary. This 
proposal is prompted by reports of failure of the NLG to extend when 
the landing gear selector was placed in the ``DOWN'' position, and 
failure of the NLG doors to open when the NLG door switch was set in 
the ``SAFETY/DOOR OPEN'' position; these conditions may have been 
caused by a reduced stroke of the spring bungee. The actions specified 
by the proposed AD are intended to prevent improper operation of the 
NLG door and consequent inability to extend the NLG due to a reduced 
stroke of the spring bungee.

DATES: Comments must be received by August 16, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-247-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 Bombardier, Inc., 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: Danko Kramar, Aerospace Engineer, 
Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft 
Certification Office, Engine and Propeller Directorate, 10 Fifth 
Street, Third Floor, Valley Stream, New York; telephone (516) 256-7509; 
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-247-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-247-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Transport Canada Aviation, which is the airworthiness authority for 
Canada, recently notified the FAA that an unsafe condition may exist on 
certain Bombardier Model CL-600-2B16 (CL-601-3A and -3R), and CL-600-
2B19 (Regional Jet Series 100) series airplanes. Transport Canada 
Aviation advises that it received reports indicating that, during 
flight of a Model CL-600-2B19 series airplane, the nose landing gear 
(NLG) did not extend when the landing gear selector was placed in the 
``DOWN'' position. The NLG did extend following cycling of the selector 
valve. Transport Canada Aviation also advises that it received a report 
indicating that, during a pre-flight check of a Model CL-600-2B16 
series airplane, the NLG doors did not open when the NLG door switch 
was set in the ``SAFETY/DOOR OPEN'' position. The cause of these 
occurrences has been attributed to a defective spring bungee assembly 
of the NLG door mechanism. Investigation revealed that the spring

[[Page 35692]]

bungee may have a reduced stroke due to incorrect clearance between the 
collar and the body of the spring bungee. This incorrect clearance was 
the result of incorrect assembly during manufacture. This condition, if 
not corrected, could result in improper operation of the NLG door, 
which could result in inability to extend the NLG.

Explanation of Relevant Service Information

    The manufacturer has issued Canadair Regional Jet Alert Service 
Bulletin A601R-32-037, Revision ``A,'' dated December 2, 1994 (for 
Model CL-600-2B19 series airplanes), and Canadair Challenger Service 
Bulletin 601-0454, dated May 15, 1995, as amended by Service Bulletin 
Information Sheet 601-0454, dated July 14, 1995 (for Model CL-600-2B16 
series airplanes). These service bulletins describe procedures for a 
one-time inspection of the spring bungee assembly of the NLG to ensure 
proper torque of the collar and correct clearance between the collar 
and the body of the bungee, and replacement of the spring bungee 
assembly with a serviceable (new or reworked) unit, if necessary. 
Transport Canada Aviation classified these service bulletins as 
mandatory and issued Canadian airworthiness directive CF-95-10, dated 
June 27, 1995, in order to assure the continued airworthiness of these 
airplanes in Canada.

FAA's Conclusions

    These airplane models are manufactured in Canada 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, 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.

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, the 
proposed AD would require a one-time inspection of the spring bungee 
assembly of the NLG to ensure proper torque of the collar and correct 
clearance between the collar and the body of the bungee, and 
replacement of the spring bungee assembly with a serviceable (new or 
reworked) unit, if necessary. The actions would be required to be 
accomplished in accordance with the service bulletins described 
previously.

Explanation of Differences between Service Bulletins and the 
Proposed Rule

    Operators should note that the compliance time specified in this 
proposed AD (within 90 days after the effective date of the AD) differs 
from the times recommended in the referenced service bulletins. [The 
compliance time recommended in Canadair Challenger Service Bulletin 
601-0454 for Model CL-600-2B16 series airplanes is ``at the next 300-
hour check.'' Canadair Regional Jet Alert Service Bulletin A601R-32-037 
(for Model CL-600-2B19 series airplanes) recommends a compliance time 
of no later than the next ``A'' check or within the next three months 
after receipt of the alert service bulletin.] The FAA finds that the 
compliance time should not differ for each airplane model, since the 
spring bungee installed on both models has the same part number. In 
developing an appropriate compliance time for this AD, the FAA also 
considered not only the degree of urgency associated with addressing 
the subject unsafe condition, but availability of replacement parts and 
the maximum interval of time allowable for all affected airplanes to 
continue to operate without compromising safety. The FAA finds 90 days 
to be an appropriate compliance time for accomplishing these actions.

Cost Impact

    The FAA estimates that 101 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 4 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$24,240, or $240 per airplane.
    The cost impact figure discussed above 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.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

    Bombardier, Inc. (Formerly Canadair): Docket 95-NM-247-AD.

    Applicability: Model CL-600-2B16 (CL-601-3A and -3R), serial 
numbers 5100 through 5166 inclusive; and Model CL-600-2B19 (Regional 
Jet Series 100) series airplanes, serial numbers 7003 through 7048 
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 request approval for an 
alternative method of compliance in accordance with paragraph (d) 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

[[Page 35693]]

been eliminated, the request should include specific proposed 
actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent improper operation of the nose landing gear (NLG) 
door and consequent inability to extend the NLG due to a reduced 
stroke of the spring bungee, accomplish the following:
    (a) Within 90 days after the effective date of this AD: Perform 
a one-time inspection of the spring bungee assembly of the NLG to 
ensure proper torque of the collar and correct clearance between the 
collar and the body of the bungee; in accordance with Canadair 
Regional Jet Alert Service Bulletin A601R-32-037, Revision `A,' 
dated December 2, 1994 (for Model CL-600-2B19 series airplanes); or 
Canadair Challenger Service Bulletin 601-0454, dated May 15, 1995, 
as amended by Service Bulletin Information Sheet 601-0454, dated 
July 14, 1995 (for Model CL-600-2B16 series airplanes); as 
applicable.
    (b) If improper torque of the collar is found, or if incorrect 
clearance between the collar and the body of the bungee is found: 
Prior to further flight, replace the spring bungee assembly with a 
serviceable (new or reworked) unit that has been inspected in 
accordance with Canadair Regional Jet Alert Service Bulletin A601R-
32-037, Revision ``A'', dated December 2, 1994 (for Model CL-600-
2B19 series airplanes); or Canadair Challenger Service Bulletin 601-
0454, dated May 15, 1995, as amended by Service Bulletin Information 
Sheet 601-0454, dated July 14, 1995 (for Model CL-600-2B16 series 
airplanes); as applicable. Accomplish the replacement in accordance 
with the applicable service bulletin.
    (c) As of the effective date of this AD, no person shall install 
a spring bungee assembly having part number 600-86115-1 (for Model 
CL-600-2B16 series airplanes) or 600-86115-5/70 (for Model CL-600-
2B19 series airplanes) on any airplane unless that assembly has been 
inspected and reworked, as necessary, in accordance with paragraph 
(a) of this AD.
    (d) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.
    (e) 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 July 1, 1996.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-17218 Filed 7-5-96; 8:45 am]
BILLING CODE 4910-13-P