AD 94-08-02 ACTIVE

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.

Final rule

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 thecompliance 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:

Service Bulletin
Number and Date
Page Number
Revision Level
Shown on Page
Date
Shown on PageATP-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.)

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.)

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.

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.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

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.

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.