Airworthiness Directives; Jetstream Model ATP Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-169-AD; Amendment 39-8873; AD 94-08-02]

Airworthiness Directives; Jetstream Model ATP Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

applicable to certain Jetstream Model ATP series airplanes, that

requires modification of the wiring for the electric-powered disconnect

unit for the elevator control system and a subsequent functional test

of the elevator control system. This amendment is prompted by an in-

service report of damaged wire insulation in the electrical power

circuit for the elevator disconnect unit, which resulted in grounding

of the circuit and consequent uncommanded operation of the disconnect

unit. The actions specified by this AD are intended to prevent

uncommanded operation of the elevator disconnect unit, which would

result in single elevator operation and, consequently, reduced

controllability of the airplane.

DATES: Effective May 23, 1994.

The incorporation by reference of certain publications listed in

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

of May 23, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Jetstream Aircraft, Inc., P.O. Box 16029, Dulles

International Airport, Washington, DC 20041-6029. 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 Office of the Federal Register, 800 North Capitol

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

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2148; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to certain Jetstream Model ATP series airplanes was

published in the Federal Register on December 6, 1993 (58 FR 64199).

That action proposed to require modification of the wiring for the

electric-powered disconnect unit for the elevator control system and a

subsequent functional test of the elevator control system.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the single comment received.

The commenter supports the proposal.

Since the issuance of the notice, Jetstream Aircraft Limited has

issued Revision 2 of Service Bulletin ATP-27-49-1023A, dated November

23, 1993. This revision of the service bulletin is essentially

identical to Revision 1, which was referenced in the notice, but

contains corrections of certain minor errors. It also excludes two

airplanes (Aircraft Constructor's numbers 2046 and 2047) from the

effectivity listing, since these airplanes are not subject to the

addressed unsafe condition. The FAA has revised the applicability of

the final rule to exclude these two airplanes. The FAA has also revised

paragraph (a) of the final rule to include a reference to Revision 2 of

the service bulletin as an additional source of appropriate service

information.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the changes previously

described. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

The FAA estimates that 10 airplanes of U.S. registry will be

affected by this AD, that it will take approximately 8 work hours per

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

rate is $55 per work hour. Required parts will cost approximately $25

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

on U.S. operators is estimated to be $4,650, or $465 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 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:

94-08-02 Jetstream Aircraft Limited (Formerly British Aerospace):

Amendment 39-8873. Docket 93-NM-169-AD.

Applicability: Model ATP airplanes, Aircraft Constructor's numbers

2002 through 2045, inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent uncommanded operation of the elevator disconnect unit,

which would result in single elevator operation and consequent reduced

controllability of the airplane, accomplish the following:

(a) Within 6 months after the effective date of this AD, modify the

wiring for the electric-powered disconnect unit for the elevator

control system (Modification 10234A); and, prior to further flight

after modification, perform a functional test of the elevator control

system; in accordance with BAe ATP Service Bulletin ATP-27-49-10234A,

Revision 1, dated August 14, 1993, or Revision 2, dated November 23,

1993.

(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, Standardization Branch, ANM-113, FAA,

Transport Airplane Directorate. Operators shall submit their requests

through an appropriate FAA Principal Maintenance Inspector, who may add

comments and then send it to the Manager, Standardization Branch, ANM-

113.

Note: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

(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.

(d) The modification shall be done in accordance with the following

BAe ATP service bulletins, which contain the following list of

effective pages:

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Service bulletin number and date Page No. Revision level shown on page Date shown on page

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ATP-27-49-10234A, Revision 1, August 14, 1993.. 1-5, 7, 9, 11, 13, 15 1 August 14, 1993

6, 8, 10, 12, 14 (These pages are not used.) (These pages are not used.)

ATP-27-49-10234A, Revision 2, November 23, 1993 1-5, 7, 9, 11, 13 2 November 23, 1993

6, 8, 10, 12 (These pages are not used.) (These pages are not used.)

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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 Jetstream Aircraft, Inc., P.O. Box 16029,

Dulles International Airport, Washington, DC 20041-6029. Copies may be

inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,

SW., Renton, Washington; or at the Office of the Federal Register, 800

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

(e) This amendment becomes effective on May 23, 1994.

Issued in Renton, Washington, on March 31, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-8176 Filed 4-20-94; 8:45 am]

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