Airworthiness Directives; De Havilland Model DHC-8 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-20-AD; Amendment 39-9005; AD 94-17-10]

Airworthiness Directives; De Havilland Model DHC-8 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

applicable to all de Havilland Model DHC-8 series airplanes, that

requires removal of the aluminum or brass hardware in the firewall

terminal block and battery shunt cable assemblies and replacement with

steel hardware. This amendment is prompted by the results of an

investigation, which revealed that corroded aluminum washers in the DC

firewall terminal block and battery shunt cable assemblies may loosen

the electrical connections. The actions specified by this AD are

intended to prevent interruption of DC electrical power due to

connections that may have loosened from corrosion.

DATES: Effective September 21, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of September 21, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Bombardier, Inc., Bombardier Regional Aircraft Division,

Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information

may be examined at the Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 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; or at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an airworthiness

directive (AD) that is applicable to all de Havilland Model DHC-8

series airplanes was published in the Federal Register on April 22,

1994 (59 FR 19152). That action proposed to require removal of the

aluminum or brass hardware in the firewall terminal block and battery

shunt cable assemblies and replacement with steel hardware

(Modification 8/1984).

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were submitted in response

to the proposal or the FAA's determination of the cost to the public.

The FAA has determined that air safety and the public interest require

the adoption of the rule as proposed.

The FAA estimates that 130 airplanes of U.S. registry will be

affected by this AD, that it will take approximately 3 work hours per

airplane to accomplish the required actions, and that the average labor

rate is $55 per work hour. Required parts will be nominal in cost.

Based on these figures, the total cost impact of the AD on U.S.

operators is estimated to be $21,450, or $165 per airplane.

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

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.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it 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 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. 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:

94-17-10 De Havilland, Inc.: Amendment 39-9005. Docket 94-NM-20-AD.

Applicability: All Model DHC-8 series airplanes, certificated in

any category. -

Compliance: Required as indicated, unless accomplished

previously.

To prevent interruption of DC electrical power due to

connections that may have loosened from corrosion, accomplish the

following:

(a) Within 60 days after the effective date of this AD, remove

the aluminum or brass hardware in the firewall terminal block and

battery shunt cable assemblies and replace with steel hardware

(Modification 8/1984), in accordance with de Havilland Service

Bulletin S.B. 8-24-47, Revision `A,' dated November 29, 1993.

(b) As of the effective date of this AD, no person shall install

on any airplane a terminal block, part number 72470052-101 or

82450068-001, unless it has been previously reworked and bears the

identification 8/1984.

(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: 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

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.

(e) The removal and replacement shall be done in accordance with

de Havilland Service Bulletin S.B. 8-24-47, Revision `A,' dated

November 29, 1993. This incorporation by reference was approved by

the Director of the Federal Register in accordance with 5 U.S.C.

552(a) and 1 CFR part 51. Copies may be obtained from Bombardier,

Inc., Bombardier Regional Aircraft Division, Garratt Boulevard,

Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected 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; or at the Office of the Federal

Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment becomes effective on September 21, 1994.

Issued in Renton, Washington, on August 11, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-20158 Filed 8-19-94; 8:45 am]

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