Airworthiness Directives; Canadair Model CL-600-2B19 ``Regional Jet'' Series 100 Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-230-AD; Amendment 39-8791; AD 94-01-09]

Airworthiness Directives; Canadair Model CL-600-2B19 ``Regional

Jet'' Series 100 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that

is applicable to Canadair Model CL-600-2B19 ``Regional Jet'' Series 100

airplanes. This action requires a revision to the Airplane Flight

Manual (AFM) to limit altitude and airspeed operations of the airplane

under certain conditions of hydraulic system failure. This amendment is

prompted by a report of sheared-off shear pins found on one airplane's

elevator dampers. The actions specified in this AD are intended to

prevent undampened vibration of the elevators in normal cruise

conditions when combined with hydraulic system failures, a condition

which could result in reduced controllability of the airplane.

DATES: Effective January 26, 1994.

Comments for inclusion in the Rules Docket must be received on or

before March 14, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 93-NM-230-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

FOR FURTHER INFORMATION CONTACT: Franco Pieri, Aerospace Engineer,

Airframe Branch, ANE-172, New York Aircraft Certification Office, FAA,

Engine and Propeller Directorate, 181 South Franklin Avenue, room 202,

Valley Stream, New York 11581; telephone (516) 791-6221; fax (516) 791-

9024.

SUPPLEMENTARY INFORMATION: 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

``Regional Jet'' Series 100 airplanes. Transport Canada Aviation

advises that one operator of these airplanes found that the shear pins

on the airplane elevator dampers had sheared off. This finding was made

during a routine check of the airplane. The cause of the pin failure

has not been determined. Failure of the shear pins on the elevator

damper, if not detected and corrected, may lead to undampened vibration

of the elevators during normal cruise conditions when combined with

hydraulic system failures. This situation could result in reduced

controllability of the airplane.

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.

In order to assure the continued airworthiness of these airplanes

in Canada, Transport Canada Aviation issued a Canadian airworthiness

directive on December 17, 1993, that restricts operation of these

airplanes to certain altitude and airspeed limits under various

conditions of hydraulic system failure. 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, this AD is being issued to prevent undampened

vibration of the elevators during normal cruise conditions in the event

of hydraulic system failures, which could result in reduced

controllability of the airplane. This AD requires a revision to the

Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to

restrict altitude and airspeed operations under conditions of single or

double hydraulic failure.

This is considered interim action until final action is identified,

at which time the FAA may consider additional rulemaking.

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All

communications received on or before the closing date for comments will

be considered, and this rule may be amended in light of the comments

received. Factual information that supports the commenter's ideas and

suggestions is extremely helpful in evaluating the effectiveness of the

AD action and determining whether additional rulemaking action would be

needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD 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-230-AD.'' The postcard will be date stamped and

returned to the commenter.

The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and is not a ``significant regulatory action''

under Executive Order 12866. It has been determined further that this

action involves an emergency regulation under DOT Regulatory Policies

and Procedures (44 FR 11034, February 26, 1979). If it is determined

that this emergency regulation otherwise would be significant under DOT

Regulatory Policies and Procedures, a final regulatory evaluation will

be prepared and placed in the Rules Docket. A copy of it, if filed, may

be obtained from the Rules Docket at the location provided under the

caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 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:

94-01-09 Canadair: Amendment 39-8791. Docket 93-NM-230-AD.

Applicability: Model CL-600-2B19 ``Regional Jet'' Series 100

airplanes; serial numbers 7003 and subsequent; certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent undampened vibration of the elevators during normal

cruise conditions in the event of hydraulic system failures, which

could result in reduced controllability of the airplane, accomplish

the following:

(a) Within 30 days after the effective date of this AD, revise

the Limitations Section of the FAA-approved Airplane Flight Manual

(AFM) to include the following restrictions of altitude and airspeed

operations under conditions of single or double hydraulic system

failure; and advise the flight crew of these revised limits.

Revision of the AFM may be accomplished by inserting a copy of this

AD in the AFM.

Note 1: The restrictions described in the AFM Temporary Revision

(TR) RJ/30 meet the requirements of this paragraph. Therefore,

inserting a copy of TR RJ/30 in lieu of this AD in the AFM is

considered an acceptable means of compliance with this paragraph.

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Altitude limit

(maximum) Airspeed limit (maximum)

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Single Hydraulic

System Failure:

31,000 feet....... 0.55 Mach (199 KIAS).

30,000 feet....... 0.55 Mach (204 KIAS).

28,000 feet....... 0.55 Mach (213 KIAS).

26,000 feet....... 0.55 Mach (222 KIAS).

24,000 feet....... 0.55 Mach (232 KIAS).

22,000 feet....... 0.55 Mach (241 KIAS).

20,000 feet and 252 KIAS.

below.

Double Hydraulic

System Failure:

10,000 feet....... 200 KIAS.

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(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 FAR

21.197 and 21.199 to operate the airplane to a location where the

requirements of this AD can be accomplished.

(d) This amendment becomes effective on January 26, 1994.

Issued in Renton, Washington, on January 3, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-344 Filed 1-10-94; 8:45 am]

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