AD 98-21-13 ACTIVE

This amendment adopts a new airworthiness directive (AD) that applies to certain British Aerospace Jetstream Model 3101 airplanes. This AD requires 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. 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 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.

Final rule

98-21-13 BRITISH AEROSPACE: Amendment 39-10822; 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, ifthe 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 Service Bulletin 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 adjustmentsin accordance with the ACCOMPLISHMENT INSTRUCTIONS section in British Aerospace Alert Service Bulletin Jetstream 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 AirplaneDirectorate.

(e) Questions or technical information related to British Aerospace Alert Service Bulletin Jetstream 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986, and Jetstream Service Bulletin 22-A-JA 860413, ORIGINAL ISSUE: 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.

(f) The replacement, inspections, and possible adjustments required by this AD shall be done in accordance with British Aerospace Alert Service Bulletin Jetstream 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986, and Jetstream Service Bulletin 22-A-JA 860413, ORIGINAL ISSUE: April 16, 1986. 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 Alert Service Bulletin Jetstream 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986, and Jetstream Service Bulletin 22-A-JA 860413, ORIGINAL ISSUE: April 16, 1996. These service bulletins are classified as mandatory by the United Kingdom Civil Aviation Authority (CAA).

(g) This amendment becomes effective on November 20, 1998

Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain British Aerospace Jetstream Model 3101 airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on June 17, 1998 (63 FR 33018). The NPRM proposed to require replacing the elevator trim servo motor with one 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. Accomplishment of the proposed actions as specified in the NPRM would be in accordance with Jetstream Service Bulletin 22-A-JA 860413, ORIGINAL ISSUE: April 16, 1986, and British Aerospace Alert Service Bulletin Jetstream 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986.

The NPRM was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Cost Impact
The FAA estimates that 25 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 6 workhours per airplane to accomplish this 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 this AD on U.S. operators is estimated to be $9,000, or $360 per airplane.

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 final evaluation prepared for this action is contained 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:

Service information that applies to this AD may be obtained from British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This information may also be examined at 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; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

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