[Federal Register Volume 63, Number 71 (Tuesday, April 14, 1998)]
[Proposed Rules]
[Pages 18160-18163]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-9755]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-83-AD]
RIN 2120-AA64


Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional 
Jet Series 100) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the supersedure of an existing 
airworthiness

[[Page 18161]]

directive (AD), applicable to certain Bombardier Model CL-600-2B19 
(Regional Jet Series 100) series airplanes, that currently requires a 
revision to the Airplane Flight Manual (AFM) to prohibit the use of 
mach trim and to add speed restrictions if the autopilot is disengaged 
or inoperative. That AD also requires installation of an associated 
placard. This proposed AD would add requirements for replacement of the 
horizontal stabilizer trim control unit (HSTCU) with a new HSTCU, and 
reactivation of the mach trim engage/disengage switch/light (if 
deactivated). Accomplishment of these actions would terminate the 
requirements of the existing AD. This proposed AD also would limit 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 prevent deficiencies of the HSTCU, which could result in a 
nose-up trim runaway when a single component in the mach trim circuit 
fails.

DATES: Comments must be received by May 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-83-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: Peter Cuneo, Aerospace Engineer, 
Systems and Flight Test 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) 256-7506; 
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 97-NM-83-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. 97-NM-83-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On July 24, 1995, the FAA issued AD 95-13-04, amendment 39-9325 (60 
FR 38668, July 28, 1995), applicable to certain Bombardier Model CL-
600-2B19 (Regional Jet Series 100) series airplanes, to require a 
revision to the Airplane Flight Manual (AFM) to prohibit the use of 
mach trim and to add speed restrictions if the autopilot is disengaged 
or inoperative. That AD also requires installation of an associated 
placard. That action was prompted by deficiencies that were discovered 
during a review of vendor documentation of the horizontal stabilizer 
trim control unit (HSTCU). The requirements of that AD are intended to 
prevent such deficiencies, which could result in a nose-up trim runaway 
when a single component in the mach trim circuit fails.

Actions Since Issuance of Previous Rule

    In the preamble to AD 95-13-04, the FAA specified that the actions 
required by that AD were considered ``interim action.'' The FAA 
indicated that it may consider further rulemaking action once a 
terminating modification was developed, approved, and available. The 
manufacturer now has developed such a modification (an improved HSTCU), 
and the FAA has determined that further rulemaking action is indeed 
necessary in order to address the unsafe condition and ensure the 
continued safe operation of those airplanes; this proposed AD follows 
from that determination.

Explanation of Relevant Service Information

    Bombardier has issued Canadair Regional Jet Service Bulletin 601R-
27-053, dated May 27, 1996; Revision A, dated August 26, 1996; and 
Revision B, dated February 21, 1997; which describes procedures for 
installation of a new HSTCU and reactivation of the mach trim engage/
disengage switch/light. The service bulletins also limit the 
effectivity listing of the airplanes. Accomplishment of the actions 
specified in the service bulletin is intended to adequately address the 
identified unsafe condition. Transport Canada Aviation (TCA), which is 
the airworthiness authority for Canada, classified this service 
bulletin as mandatory and issued Canadian airworthiness directive CF-
95-08R2, dated July 23, 1996, in order to assure the continued 
airworthiness of these airplanes in Canada.

FAA's Conclusions

    This airplane model is manufactured in Canada and is 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, TCA has kept the FAA informed of the 
situation described above. The FAA has examined the findings of TCA, 
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 95-13-04 to 
continue to

[[Page 18162]]

require a revision to the AFM to prohibit the use of mach trim and to 
add speed restrictions if the autopilot is disengaged or inoperative, 
and installation of an associated placard.
    This new proposed AD would add requirements for replacement of the 
HSTCU with a new unit, and reactivation of the mach trim engage/
disengage switch/light (if deactivated). Accomplishment of these 
actions would constitute terminating action for the requirements of the 
existing AD. The replacement and reactivation would be required to be 
accomplished in accordance with the service bulletin described 
previously.
    This proposed AD also limits the applicability of the existing AD 
to airplanes having certain serial numbers. The manufacturer has 
notified the FAA that for serial numbers 7113 and subsequent, the 
airplane will be modified during production.

Cost Impact

    There are approximately 54 Bombardier Model CL-600-2B19 (Regional 
Jet Series 100) series airplanes of U.S. registry that would be 
affected by this proposed AD.
    The actions that are currently required by AD 95-13-04 take 
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 $6,480, or $120 per airplane.
    The new actions that are proposed in this AD action would take 
approximately 3 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would be provided by 
the manufacturer at no cost to the operator. Based on these figures, 
the cost impact of the proposed requirements of this AD on U.S. 
operators is estimated to be $9,720, or $180 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 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 removing amendment 39-9325 (60 FR 
38668, July 28, 1995), and by adding a new airworthiness directive 
(AD), to read as follows:

Bombardier, Inc. (Formerly Canadair): Docket 97-NM-83-AD. Supersedes 
AD 95-13-04, Amendment 39-9325.

    Applicability: Model CL-600-2B19 (Regional Jet Series 100) 
series airplanes, serial numbers 7003 through 7112 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)(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 prevent deficiencies of the horizontal stabilizer trim 
control unit (HSTCU), which could result in a nose-up trim runaway 
when a single component in the mach trim circuit fails, accomplish 
the following:

Restatement of Requirements of AD 95-13-04

    (a) Within 24 hours after August 14, 1995 (the effective date of 
AD 95-13-04, amendment 39-9325), accomplish the requirements of 
paragraphs (a)(1), (a)(2), and (a)(3) of this AD.
    (1) Install a placard adjacent to the primary flight display 
next to the airspeed limitation placard, to read:
    ``USE OF MACH TRIM IS PROHIBITED. IF THE AUTOPILOT IS DISENGAGED 
OR INOPERATIVE, RESTRICT SPEED TO 250 KIAS OR 0.7 MACH.''

    (2) Revise the Limitations section of the FAA-approved Airplane 
Flight Manual (AFM) to include the following information. The 
requirements of this paragraph may be accomplished by inserting a 
copy of this AD, or Canadair Regional Jet Temporary Revision No. TR 
RJ/43, into the AFM.

    ``USE OF MACH TRIM IS PROHIBITED. IF THE AUTOPILOT IS DISENGAGED 
OR INOPERATIVE, RESTRICT SPEED TO 250 KIAS OR 0.7 MACH.''

    Note 2: When the temporary revision has been incorporated in the 
general revisions of the AFM, the general revisions may be inserted 
in the AFM, provided the information contained in the general 
revision is identical to that specified in Canadair Regional Jet 
Temporary Revision No. TR RJ/43.

    (3) Revise the Limitations section of the FAA-approved AFM to 
include the following information. The requirements of this 
paragraph may be accomplished by inserting a copy of this AD into 
the AFM.

    ``Prior to the accomplishment of Bombardier Alert Service 
Bulletin S.B. A601R-27-054, dated June 12, 1995, when the Mach trim 
system is disengaged, the ``MACH TRIM'' caution message will be 
displayed on the Engine Indication and Crew Alerting System (EICAS), 
and the Mach trim engage/disengage switch ``INOP'' legend will be 
illuminated. The EICAS message may be scrolled out of view prior to 
takeoff, but the switch ``INOP'' light will remain illuminated.''

New Requirements of this Ad

    (b) Within 18 months after the effective date of this AD, 
replace the HSTCU with a new HSTCU having part number 601R92301-9, 
and reactivate the mach trim switch/light (if deactivated), in 
accordance with Bombardier Service Bulletin 601R-27-053, dated May 
27, 1996; Revision A, dated August 26, 1996; or Revision B, dated 
February 21, 1997. Accomplishment of this modification constitutes 
terminating action for the requirements of paragraph (a) of this AD; 
after the modification has been

[[Page 18163]]

accomplished, the previously required AFM limitation may be removed.
    (c) As of the effective date of this AD, no person shall install 
any HSTCU having part number 601R92301-5, 601R92301-7, or 601R92301-
951 on any airplane.
    (d)(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, 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.
    (d)(2) Alternative methods of compliance approved previously in 
accordance with AD 93-13-04, amendment 39-9325, 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 New York ACO.
    (e) Special flight permits may be issued in accordance with 
Secs. 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 Canadian 
airworthiness directive CF-95-08R2, dated July 23, 1996.

    Issued in Renton, Washington, on April 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-9755 Filed 4-13-98; 8:45 am]
BILLING CODE 4910-13-P