Airworthiness Directives; Canadair Model CL-600-2B16 (CL-601-3A) Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-222-AD]

Airworthiness Directives; Canadair Model CL-600-2B16 (CL-601-3A)

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-600-2B16

series airplanes. This proposal would require inspection to detect

chafing of the wiring harness of the air driven generator (ADG),

modification of the wiring harness, and repair of any chafed harness.

This proposal is prompted by a report that the wiring harness on

certain airplanes were produced in a configuration that is subject to

chafing and electrical shorting. The actions specified by the proposed

AD are intended to prevent loss of ADG power to the essential bus when

the ADG is deployed during an emergency situation.

DATES: Comments must be received by May, 9, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 93-NM-222-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, room 202, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT: Michele Maurer, Aerospace 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-222-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-222-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

On August 23, 1991, the FAA issued AD 91-19-01, Amendment 39-8026

(56 FR 45893, September 9, 1991), applicable to certain Canadair Model

CL-600-1A11, CL-600-2A12, and CL-600-2B16 series airplanes. That AD

requires inspection to detect chafing and modification of the wiring

harness of the air driven generator (ADG), and repair of any chafed

harness. That action was prompted by reports of chafing of the ADG

electrical output harness against the backshell of the connector on the

turbine generator assembly. Although the chafing occurred while the ADG

was in the stowed position, when the ADG was deployed, the chafed wires

shorted to the airplane structure and prevented the ADG from powering

the essential bus. This essential bus provides electrical power to the

hydraulic flight control system and to the essential flight control

equipment. In these instances, the shorting also damaged the ADG output

harness and its support structure.

This condition, if not corrected, could result in loss of emergency

power to the essential bus when the ADG is deployed.

Since issuance of AD 91-19-01, Transport Canada Aviation, which is

the airworthiness authority for Canada, notified the FAA that the same

unsafe condition addressed in AD 91-19-01 may exist on certain

additional Model CL-600-2B16 series airplanes. Transport Canada

Aviation advises that, during production of Model CL-600-2B16 series

airplanes having serial numbers 5099 through 5131, inclusive, the

wiring harnesses of the ADG's were not modified to preclude chafing

against the backshell of the connector on the turbine generator

assembly. (AD 91-19-01 is applicable only to airplanes having serial

numbers 5001 through 5098, inclusive.) Therefore, these airplanes are

also subject to losing ADG power to the essential bus when the ADG is

deployed during an emergency situation.

Canadair has issued Alert Service Bulletin A601-0370, Revision 1,

dated April 15, 1993, that describes procedures for a one-time

inspection to detect chafing and modification of the ADG wiring

harness, and repair of any chafed harness. This modification entails

replacing two existing harness support brackets with redesigned

brackets that would preclude chafing of the harness. The effectivity of

this service bulletin includes Model CL-600-2B16 series airplanes

having serial numbers 5099 through 5131 only. Transport Canada Aviation

classified this alert service bulletin as mandatory and issued Canadian

Airworthiness Directive CF-91-21R1, dated May 6, 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

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 inspection to

detect chafing and modification of the wiring harness of the ADG, and

repair of any chafed harness. The actions would be required to be

accomplished in accordance with the alert service bulletin described

previously. This proposed AD would apply only to airplanes having

serial numbers 5099 through 5131, inclusive.

Note: The FAA's normal policy is that when an AD requires a

substantive change, such as a change in its applicability, the

``old'' AD is superseded by removing it from the system and a new AD

is added. In the case of this AD action, the FAA normally would have

proposed superseding AD 91-19-01 to expand its applicability to

include the additional affected airplanes. However, in

reconsideration of the entire fleet size that would be affected by a

supersedure action, and the consequent workload associated with

revising maintenance record entries, the FAA has determined that a

less burdensome approach is to issue a separate AD applicable only

to these additional airplanes. This AD does not supersede AD 91-19-

01; airplanes listed in the applicability of AD 91-19-01 are

required to continue to comply with the requirements of that AD.

This proposed AD is a separate AD action, and is applicable only to

airplanes having serial numbers 5099 through 5131, inclusive.)

The FAA estimates that 25 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 1 work

hour per airplane to accomplish the proposed inspection, and that the

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

total cost impact of the proposed inspection on U.S. operators is

estimated to be $1,375, or $55 per airplane.

The FAA estimates that it would take approximately 9 work hours per

airplane to accomplish the proposed modification and the average labor

rate is $55 per work hour. Required parts would cost approximately $199

per airplane. Based on these figures, the total cost impact of the

proposed modification on U.S. operators is estimated to be $17,350 or

$694 per airplane.

Based on the figures, above, the total (inspection plus

modification) cost impact of the proposed AD on U.S. operators is

estimated to be $18,725 or $749 per airplane.

The total 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.

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: Docket 93-NM-222-AD.

Applicability: Model CL-600-2B16 series airplanes having serial

numbers 5099 through 5131, inclusive; certificated in any category.

Note 1: Airplanes having serial numbers 5001 through 5098,

inclusive, are subject to the requirements of AD 91-19-01, Amendment

39-8026.

Compliance: Required as indicated, unless accomplished

previously.

To prevent loss of emergency power to the essential bus when the

air driven generator (ADG) is deployed, accomplish the following:

(a) Within 25 hours time-in-service after the effective date of this

AD, inspect to detect chafing of the wiring harness of the ADG in

accordance with Canadair Alert Service Bulletin A601-0370, Revision

1, dated April 15, 1993. If chafing is found, prior to further

flight, repair in accordance with the service bulletin.

(b) Within 60 days after the effective date of this AD, modify

the harness installation of the ADG in accordance with Canadair

Alert Service Bulletin A601-0370, Revision 1, dated April 15, 1993.

(c) 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.

(d) 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 March 8, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-5851 Filed 3-11-94; 8:45 am]

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