[Federal Register Volume 59, Number 43 (Friday, March 4, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-4955]


[[Page Unknown]]

[Federal Register: March 4, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-213-AD]

 

Airworthiness Directives; Canadair Model CL-600-2B19 (Regional 
Jet) 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 Canadair Model CL-600-2B19 
(Regional Jet) series airplanes. This proposal would require 
modification of the stall protection system (SPS) input wiring, a 
revision to the FAA-approved Airplane Flight Manual (AFM) to specify 
that a pre-flight check of the slip/skid indications must be conducted 
prior to engine start; and modification of the attitude and heading 
reference system (AHRS). This proposal is prompted by a report that the 
AHRS could send conflicting input to the stall protection computer 
(SPC) on the airplane. The actions specified by the proposed AD are 
intended to prevent the loss of stall warning protection on the 
airplanes.

DATES: Comments must be received by April 29, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-213-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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 A, Montreal, 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, 181 South Franklin 
Avenue, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: Peter Cuneo, Electrical Engineer, 
Systems and Equipment Branch, ANE-173, FAA, Engine and Propeller 
Directorate, New York Aircraft Certification Office, 181 South Franklin 
Avenue, room 202, Valley Stream, New York 11581; telephone (516) 791-
6427; fax (516) 791-9024.

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 93-NM-213-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. 93-NM-213-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 Canadair Model CL-600-2B19 series airplanes. Transport 
Canada advises that the attitude and heading reference system (AHRS) 
could send conflicting input to the stall protection computer (SPC) on 
these airplanes. When the AHRS sends input to the SPC, the left- and 
right-hand channels on the SPC receive and compare that input. The SPC 
has a built-in feature that compares lateral acceleration from these 
channels. When the SPC recognizes unequal lateral acceleration signals 
of 0.03g or higher, it will inhibit the stall horn, light, and stick 
push command, and an ``SPS FAILURE'' caution message will display on 
the primary flight display. Due to a build-up effect of AHRS 
tolerances, these unequal signals may be detected within the SPC at a 
roll rate within the normal flight envelope. This condition, if not 
corrected, could result in the loss of stall warning protection on the 
airplane.
    Bombardier, Inc., has issued Regional Jet Canadair Alert Service 
Bulletin S.B. A601R-34-028, Revision `A,' dated October 22, 1993, that 
describes procedures for modification of the stall protection system 
(SPS) input wiring. The modification involves removing the right 
channel input wires from the connection to the SPC, capping and stowing 
the removed wires, installing splices from the left-hand channel input 
to the right-hand channel connection of the SPC, and installing a 
ground jumper wire. Accomplishment of these wiring changes will prevent 
a build-up effect of AHRS tolerances and unequal signals between the 
left- and right-hand SPC channels. Transport Canada Aviation classified 
this service bulletin as mandatory and issued Canadian Airworthiness 
Directive CF-93-27, dated October 26, 1993, in order to assure the 
continued airworthiness of these airplanes in Canada.
    -This airplane model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
Section 21.29 of the Federal Aviation Regulations 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 require modification of the 
SPS input wiring. The modification would be required to be accomplished 
in accordance with the alert service bulletin described previously.
    -This proposed AD would also require revising the Normal Procedures 
section of the FAA-approved Airplane Flight Manual (AFM) to specify 
that a pre-flight check of the slip/skid indications must be conducted 
prior to engine start. Finally, this proposed AD would require 
modification of the AHRS to restore the dual AHRS inputs to the SPC. 
This modification would be required to be accomplished in accordance 
with a method approved by the FAA.
    -It should be noted that Canadian AD CF-93-27 requires that the 
flight crew be advised of the possibility of an inadvertent inhibition 
of the stall horn, light, and stick push command at a roll rate within 
the normal flight envelope, and that an ``SPS FAILURE'' caution message 
will be displayed on the primary flight display. The Canadian AD 
requires that when such a message is displayed, appropriate abnormal 
procedures in the AFM should be followed. However, the FAA's position 
in this regard is that it is not necessary to include a requirement in 
this proposed AD to direct the flight crew to follow existing AFM 
procedures.
    -The FAA estimates that 9 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 2 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $55 per work hour. The cost for required parts 
would be minimal. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $990, or $110 per 
airplane. This total cost figure assumes that no operator has yet 
accomplished the proposed requirements of this AD action.
    -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 14 
CFR part 39 of the Federal Aviation Regulations 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 adding the following new 
airworthiness directive:


Canadair Limited: Docket 93-NM-213-AD.

    Applicability: Model CL-600-2B19 series airplanes, serial 
numbers 7003 through 7026 inclusive, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the loss of stall warning protection on the airplane, 
accomplish the following:
    (a) Within 30 days after the effective date of this AD, modify 
the stall protection system (SPS) input wiring, in accordance with 
Canadair Regional Jet Alert Service Bulletin A601R-34-028, Revision 
`A,' dated October 22, 1993.
    (b) Prior to further flight after accomplishment of the 
modification required by paragraph (a) of this AD, revise the Normal 
Procedures section of the FAA-approved Airplane Flight Manual (AFM) 
by inserting the following into the AFM as facing page 04-20-13 
 to advise the flight crew that a pre-flight check of the slip/
skid indications must be accomplished as a ``Before Start'' item. 
This may be accomplished by inserting a copy of this AD into the 
AFM.
    ``Change step (4) within paragraph E, Before Start, to read as 
follows:
(4) EFIS--Checked and Set
Check that no annunciations are displayed on EFIS
EFIS slip/skid indications--Normal

    Indications of a one-half (1/2) symbol width lateral deviation -
- should be interpreted as an AHRS failure.

Note

    One-half (1/2) symbol width displacement corresponds to -- 
approximately one-half displacement on a conventional inclinometer.

EFIS--Set for Departure''

    Note 1: Insertion of Canadair Regional Jet Airplane Flight 
Manual CSP A-012, Temporary Revision RJ/26, dated October 21, 1993, 
in the Normal Procedures section of the AFM is an acceptable method 
of compliance with the requirements of paragraph (b) of this AD.

    (c) Within 6 months after the effective date of this AD, modify 
the attitude and heading reference system (AHRS) to restore the dual 
AHRS inputs to the stall protection computer (SPC), in accordance 
with a method approved by the Manager, New York Aircraft 
Certification Office (ACO), FAA, Engine and Propeller Directorate.
    (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 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: 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 
Federal Aviation Regulations (FAR) 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 February 28, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-4955 Filed 3-3-94; 8:45 am]
BILLING CODE 4910-13-U