AD 98-11-31

This amendment adopts a new airworthiness directive (AD) that applies to all British Aerospace (BAe) Jetstream Model 3101 airplanes equipped with a certain autopilot. This AD requires modifying the autopilot elevator electric system relays by installing two additional relays and associated wiring changes in the relay box located under the right hand crew seat. 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 failure of the autopilot elevator electric system relays for the up and down trim interlocks, which could result in uncommanded trim servo operation and possible loss of control of the airplane.

Final rule

98-11-31 BRITISH AEROSPACE: Amendment 39-10556; Docket No. 97-CE-100-AD.
Applicability: Jetstream Model 3101 airplanes, all serial numbers, certificated in any category, that are equipped with autopilot systems installed under Jetstream Aircraft Limited (JAL) Modifications JM3027, 3243, 3352, or 3483.

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 shouldinclude specific proposed actions to address it.

Compliance: Required within the next 12 calendar months after the effective date of this AD, unless already accomplished.

To prevent failure of the autopilot elevator electric system relays for the up and down trim interlocks, which could result in uncommanded trim servo operation and possible loss of control of the airplane, accomplish the following:

(a) Modify the autopilot system with Jetstream Aircraft Ltd. (JAL) Kit No. JK2628 in accordance with Jetstream 3100/3200 Series Service Bulletin No. 22-JK 2628, Revision 2, Original Issue: October 21, 1996, by installing two additional relays in the relay box with associated wiring changes. This relay box is located under the right-hand crew seat in the cockpit.

(b) The modification required by paragraph (a) of this AD eliminates the 800-hour life limit requirement for the pitch-up and pitch-down relays. Operators are encouraged to obtain the revision for their affected maintenance manuals that is available from the manufacturer.

(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 Jetstream 3100/3200 Series Service Bulletin No. 22-JK 2628, Revision 2, Original Issue: October 21, 1996, 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 modification required by this AD shall be done in accordance with Jetstream 3100/3200 Series Service Bulletin No. 22-JK 2628, Revision 2, Original Issue: October 21, 1996. 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 the British AD No. 006-10-96, undated.

(g) This amendment becomes effective on July 17, 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 all BAe Jetstream Model 3101 airplanes equipped with certain autopilots was published in the Federal Register as a notice of proposed rulemaking (NPRM) on March 25, 1998 (63 FR 14383). The autopilot system that would be affected by the NPRM is installed under Jetstream Aircraft Limited (JAL) Modifications JM3027, 3243, 3352, or 3483. These modifications encompassed the installation of an autopilot system that has pitch-up and pitch-down relays with an 800 hour life limit. The NPRM proposed to require modifying the autopilot system by installing two additional relays and associated wiring changes in the relay box located below the right-hand crew seat in the cockpit. This modification would remove the existing 800-hour life limit on the pitch-up and pitch down relays.

Accomplishment of theproposed action as specified in the NPRM would be in accordance with Jetstream Series 3100/3200 Service Bulletin 22-JK 2628, Revision 2, Original Issue: October 21, 1996.

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.

Compliance Time of This AD
The compliance time of this AD is presented in calendar time instead of hours time-in-service (TIS). The FAA has determined that a calendar time compliance is the most desirable method because this action removes an existing 800-hour life limit on the pitch-up and pitch-down relays in the autopilot system. Therefore, to ensure that the above-referenced condition is corrected on all of the affected airplanes within a reasonable period of time without inadvertently grounding any airplanes, a compliance schedule based upon calendar time instead of hours TIS is required.

Cost Impact

The FAA estimates that 189 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. Parts cost approximately $430 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $149,310, or $790 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 beobtained 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: