Airworthiness Directives; Canadair Model CL-600-1A11, -2A12, and -2B16 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-207-AD]

Airworthiness Directives; Canadair Model CL-600-1A11, -2A12, and

-2B16 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-

1A11, -2A12, and -2B16 series airplanes. This proposal would require a

test of the engine throttle quadrant to determine if the throttle lever

bypasses the idle stop into the shut-off position, and modification of

the throttle quadrant or replacement of the throttle quadrant with a

modified unit. This proposal is prompted by reports of unintentional

engine shutdown on Model CL-600-2A12 and -2B16 series airplanes. The

actions specified by the proposed AD are intended to prevent

inadvertent shutdown of an engine while the airplane is taxiing or in

flight.

DATES: Comments must be received by April 5, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 93-NM-207-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: Raymond J. O'Neill, Aerospace

Engineer, Propulsion Branch, ANE-174, FAA, Engine and Propeller

Directorate, New York Aircraft Certification Office, 181 South Franklin

Avenue, room 202, Valley Stream, New York 11581; telephone (516) 791-

7421; 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-207-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-207-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-600-1A11, -2A12, and -2B16 series airplanes.

Transport Canada Aviation advises that it has received two reports of

unintentional engine shutdown: One incident occurred during flight on a

Model CL-600-2A12, the other occurred on a Model CL-600-2B16 while the

airplane was on the ground. In both cases, engine shutdown occurred

when the throttle lever over-rode the idle stop during throttle

retardation. The throttle lever then moved directly to the shut-off

position. -

Tests results performed on throttle quadrants that were both

installed and not installed revealed that, in some cases, the idle stop

spring-loaded pawl can be lifted sufficiently for it to pass over the

idle stop without pressure being applied to the release latch. This

condition becomes more apparent when the friction device on the

quadrant is loaded and a side load is applied to the throttle lever.

This condition, if not corrected, could result in inadvertent shutdown

of an engine while the airplane is taxiing or in flight. -

Model CL-600-1A11 series airplanes are similar in type design to

the airplane models on which the reported incidents occurred.

Therefore, all three models are subject to the addressed unsafe

condition. -

Bombardier has issued Canadair Alert Service Bulletin A600-0615,

dated June 10, 1992 (for Model CL-600-1A11 series airplanes), and

Canadair Alert Service Bulletin A601-0374 (for Model CL-600-2A12 and -

2B16 series airplanes), Revision 1, dated September 30, 1992. These

service bulletins describe procedures for a test of the engine throttle

quadrant to determine if the throttle lever bypasses the idle stop into

the shut-off position, and modification of the throttle quadrant or

replacement of the throttle quadrant with a modified unit. The

modification involves removing material from the small triangular area

on the outboard sides of both idle stop pawls to obtain specified

protrusion dimensions or foot widths, testing each throttle lever to

ensure it does not pass the idle stop into the shut-off position, and

permanently reidentifying the unit. Transport Canada Aviation

classified these service bulletins as mandatory and issued Canadian

Airworthiness Directive CF-92-23, dated November 17, 1992, in order to

assure the continued airworthiness of these airplanes in Canada. -

The Canadair alert service bulletins discussed previously reference

two service bulletins as additional sources of service information:

Sargent Aerospace Service Bulletins 43058-76-03 (for Model CL-600-1A11

series airplanes) and 43068-76-05 (for Model CL-600-2A12 and -2B16

series airplanes), both dated April 13, 1992. -

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 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 a test of the

engine throttle quadrant to determine if the throttle lever bypasses

the idle stop into the shut-off position, and modification of the

throttle quadrant or replacement of the throttle quadrant with a

modified unit. The actions would be required to be accomplished in

accordance with the Canadair alert service bulletins described

previously. -

The FAA estimates that 150 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 17 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $55 per work hour. Based on these figures, the

total cost impact of the proposed AD on U.S. operators is estimated to

be $140,250, or $935 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--[AMENDED]

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-207-AD.

Applicability: Model CL-600-1A11 series airplanes, serial

numbers 1004 through 1085 inclusive, equipped with Sargent throttle

quadrants, part numbers 600-90601-69, -71, and -73; Model CL-600-

2A12 series airplanes, serial numbers 3001 through 3066 inclusive,

equipped with Sargent throttle quadrants, part numbers 600-90601-

983, -1013, -1015, -1017, and -1019; and Model CL-600-2B16 series

airplanes, serial numbers 5001 through 5114 inclusive, equipped with

Sargent throttle quadrants, part numbers 600-90601-983, -1013, -

1015, -1017, and -1019; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent inadvertent shutdown of an engine while the airplane

is taxiing or in flight, accomplish the following:

(a) Within 50 hours time-in-service after the effective date of

this AD, perform a test of the engine throttle quadrant to determine

if the throttle lever bypasses the idle stop into the shut-off

position, in accordance with Canadair Alert Service Bulletins A600-

0615, dated June 10, 1992 (for Model CL-600-1A11 series airplanes),

or A601-0374, Revision 1, dated September 30, 1992 (for Model CL-

600-2A12 and -2B16 series airplanes), as applicable.

Note 1: Canadair Alert Service Bulletins A600-0615 and A601-0374

reference Sargent Aerospace Service Bulletins 43058-76-03 (for Model

CL-600-1A11 series airplanes) and 43058-76-05 (for Model CL-600-2A12

and -2B16 series airplanes), both dated April 13, 1992, for

additional service information.

(1) If the throttle lever bypasses the idle stop into the shut-

off position, prior to further flight, modify the throttle quadrant

or replace the throttle quadrant with a modified unit, in accordance

with the applicable service bulletin.

(2) If the throttle lever does not bypass the idle stop into the

shut-off position, within 600 landings after the effective date of

this AD, modify the throttle quadrant or replace the throttle

quadrant with a modified unit, in accordance with the applicable

service bulletin.

(b) 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.

(c) 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 3, 1994.

N.B. Martenson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-2914 Filed 2-8-94; 8:45 am]

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