Airworthiness directives: British Aerospace,

[Federal Register: June 17, 1998 (Volume 63, Number 116)]

[Proposed Rules]

[Page 33018-33019]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr17jn98-21]

[[Page 33018]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-32-AD]

RIN 2120-AA64

Airworthiness Directives; British Aerospace Jetstream Model 3101 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes to adopt a new airworthiness directive (AD) that would apply to certain British Aerospace Jetstream Model 3101 airplanes. The proposed AD would require replacing the elevator trim servo motor with a new motor of improved design and inspecting the cable tension and electrical operation of the elevator and trim tab for proper operation and making any necessary adjustments. The proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by the proposed AD are intended to prevent the elevator trim servo motor drive gear assembly from remaining engaged when the autopilot is disengaged, which could result in the pilot having to manually overpower the elevator trim control and possibly lose directional control of the airplane during critical phases of flight.

DATES: Comments must be received on or before July 24, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-CE-32-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Comments may be inspected at this location between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.

Service information that applies to the proposed AD may be obtained from British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This information also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. S.M. Nagarajan, Aerospace Engineer, FAA, Small Airplane Directorate, Aircraft Certification Service, 1201 Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-6932; facsimile: (816) 426-2169.

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 should 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 that summarizes each FAA-public contact concerned with the substance of this proposal will be filedin 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 No. 98-CE-32-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, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-CE-32-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Discussion

The Civil Airworthiness Authority (CAA), which is the airworthiness authority for the United Kingdom, notified the FAA that an unsafe condition may exist on certain British Aerospace Jetstream Model 3101 airplanes that are equipped with an autopilot. The CAA reports that an elevator trim servo motor in the autopilot failed on a Jetstream Model 3101 airplane, causing the pilot to use extreme force to manually rotate the elevator trim control handwheel. The investigation showed that the leaf spring in the solenoid assembly of the elevator trim servo motor fractured. This fracture caused the servo motor drive gear assembly to remain engaged, even with the solenoid de-energized and the autopilot disengaged. This condition occurs from residual magnetism in the solenoid core, which keeps the armature depressed.

These conditions, if not corrected, could result in loss of directional control of the airplane during critical phases of flight.

Relevant Service Information

British Aerospace has issued Jetstream Service Bulletin 22-A-JA 860413, dated April 16, 1986, which specifies procedures for replacing the elevator trim servo motor; and Jetstream Alert Service Bulletin 22- A-JA 851231, dated April 9, 1986, which specifies procedures for inspecting the cable tension and electrical operation of the elevator trim, along with testing and adjusting, if necessary, the friction and the electric trim manual override loads after the installation of the new elevator trim servo motor.

The CAA classified these service bulletins as mandatory in order to assure the continued airworthiness of these airplanes in the United Kingdom. The CAA classifying a service bulletin as mandatory is the same in the United Kingdom as the FAA issuing an AD in the United States.

The FAA's Determination

This airplane model is manufactured in the United Kingdom and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above.

The FAA has examined the findings of the CAA; reviewed all available information, including the service information referenced above; and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop in other British Aerospace Jetstream Model 3101 airplanes of the same type design registered in the United States, the FAA is proposing AD action. The proposed AD would require replacing the elevator trim servo motor with one of improved design, inspecting the cable tension and electrical operation, testing the friction and the

[[Page 33019]]

electric trim manual override loads after the new motor is installed, and making any necessary adjustments. Accomplishment of the proposed modification would be in accordance with the service bulletins previously referenced.

Cost Impact

The FAA estimates that 25 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 6 workhours per airplane to accomplish the proposed action, and that the average labor rate is approximately $60 an hour. The manufacturer will provide parts at no cost to the owner/operator. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $9,000, or $360 per airplane.

Regulatory Impact

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 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) 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 has been placed 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 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. 106(g), 40113, 44701.

    Sec. 39.13 [Amended]

  2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows:

    British Aerospace: Docket No. 98-CE-32-AD.

    Applicability: Jetstream Model 3101 airplanes, certificated in any category, with the following serial numbers, that are equipped with an autopilot:

    Serial Numbers

    601 603 604 606 607 609 610 612 614 616 620 621 622 626 629 634 637 641 645 648 649 655 665 686 690

    Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

    Compliance: Required within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

    To prevent the elevator trim servo motor drive gear assembly from remaining engaged when the autopilot is disengaged, which could result in the pilot having to manually overpower the elevator trim control, and possibly lose directional control of the airplane during critical phases of flight, accomplish the following:

    (a) Replace the elevator trim servo motor with a new elevator trim servo motor of improved design at fuselage station (F.S.) 421, aft of the rear bulkhead, in accordance with the ACCOMPLISHMENT INSTRUCTIONS section in JETSTREAM Alert Service Bulletin (SB) 22-A- JA 860413, ORIGINAL ISSUE: April 16, 1986.

    (b) Inspect the cable tension, system friction, and electric trim manual override and make any necessary adjustments in accordance with the ACCOMPLISHMENT INSTRUCTIONS section in JETSTREAM SB No. 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986.

    (c) Special flight permits may be issued in accordance with sections 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.

    (d) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Small Airplane Directorate, Aircraft Certification Service, 1201 Walnut, suite 900, Kansas City, Missouri 64106. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.

    Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small Airplane Directorate.

    (e) Questions or technical information related to British Aerospace Jetstream Service Bulletin 22-A-JA 851231, dated April 9, 1986, and Jetstream Alert Service Bulletin 22-A-JA 860413, dated April 16, 1986, should be directed to British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

    Note 3: The subject of this AD is addressed in British Aerospace Jetstream Service Bulletin 22-A-JA 851231, dated April 9, 1986, and British Aerospace Jetstream Service Bulletin 22-A-JA 860413, dated April 16, 1998. These service bulletins are classified as mandatory by the United Kingdom Civil Aviation Authority (CAA).

    Issued in Kansas City, Missouri, on June 9, 1998. Michael Gallagher, Manager, Small Airplane Directorate, Aircraft Certification Service.

    [FR Doc. 98-16024Filed6-16-98; 8:45 am]

    BILLING CODE 4910-13-U

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