AD 98-21-14

This amendment adopts a new airworthiness directive (AD) that applies to certain British Aerospace Jetstream Model 3101 airplanes. This AD requires modifying the airplane s navigational system by shortening and re-clipping the cable looms to the No. 1 and No. 2 vertical gyroscopes, installing a warning label adjacent to the gyroscopes, and performing an operational check on the system. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent a cross connection in the No. 1 and No. 2 vertical gyroscopes, which could result in navigational errors during flight.

Final rule; request for comments

98-21-14 BRITISH AEROSPACE: Amendment 39-10823; Docket No. 98-CE-33-AD.
Applicability: Jetstream Model 3101 airplanes, serial numbers 703, 705, and 707, certificated in any category.

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 (e) 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 prior to further flight after the effective date of this AD, unless already accomplished.

To prevent a cross connection in the No. 1 and No. 2 vertical gyroscopes, which could result in navigational errors during flight, accomplish the following:

(a) Modify the navigation system by shortening and re-clipping the cable looms on the No. 1 and No. 2 vertical gyroscope in accordance with the Accomplishment Instructions section of Jetstream Service Bulletin No. 34-JA 891143, dated March 2, 1990.

(b Install a warning label, part number JA-891143-K1 or an FAA-approved equivalent part number, adjacent to the No. 1 and No. 2 vertical gyroscope in accordance with the Accomplishment Instructions section of Jetstream Service Bulletin No. 34-JA 891143, dated March 2, 1990.

(c) Perform an operational check of the No. 1 and No. 2 vertical gyroscope in accordance with the Accomplishment Instructions section of Jetstream Service Bulletin No. 34- JA 891143, dated March 2, 1990. If the vertical gyroscopes do not operate correctly, prior to further flight, correct any discrepancies in accordance with the Accomplishment Instructions section of Jetstream Service Bulletin No. 34-JA 891143, dated March 2, 1990.

(d) 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.

(e) 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.

(f) Questions or technical information related to British Aerospace Jetstream SB 34- JA 891143, dated March 2, 1990, 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.

(g) The modification and operational check required by this AD shall be done in accordance with British Aerospace Jetstream Service Bulletin 34-JA 891143, dated March 2, 1990. 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 British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland. Copies may be inspected at the FAA, Central Region,Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in British Aerospace Jetstream SB 34-JA 891143, dated March 2, 1990. This service bulletin is classified as mandatory by the United Kingdom Civil Aviation Authority (CAA).

(h) This amendment becomes effective on November 2, 1998.

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. The CAA reports that the navigational system in these airplanes could malfunction with a cross connection of the No. 1 and No. 2 vertical gyroscopes.

This condition, if not corrected, could result in navigational errors during flight.

Relevant Service Information
British Aerospace has issued Jetstream Service Bulletin (SB) 34-JA 891143, dated March 2, 1990, which specifies procedures for modifying the navigation system by shortening and re-clipping the cable looms of the No. 1 and No. 2 vertical gyroscopes, installing a warning label, part number (P/N) JA-891143-K1, next to the vertical gyroscopes, and performing an operational check to assure the gyroscopes are operating correctly.

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 This AD
Since an unsafe condition has been identified that is likely to exist or develop in other Jetstream Model 3101 airplanes of the same type design, this AD requires modifying the navigation system by shortening and re-clipping the cable looms on the No. 1 and No. 2 vertical gyroscopes, installing a warning label adjacent to the vertical gyroscopes, and performing an operational check to assure correct operation of the vertical gyroscopes. The actions are to be done in accordance with the instructions in British Aerospace Jetstream SB 34-JA 891143, dated March 2, 1990.

Cost Impact
None of the Jetstream Model 3101 airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers this rule necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register.

Should an affected airplane be imported and placed on the U.S. Register, accomplishment of the required modification would take approximately 8 workhours at an average labor charge of $60 per workhour. Based on these figures, the total cost impact of this AD would be $480 per airplane that would become registered in the United States.

The Effective Date of This AD
Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.

Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered,and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 98-CE-33-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
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 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, 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. 106(g), 40113, 44701.

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