AD 98-21-25

This amendment adopts a new airworthiness directive (AD) that applies to certain British Aerospace Jetstream Models 3101 and 3201 airplanes that are equipped with the ground inhibit function (Modification JM7813A (SB 27-JM7813A) or JM7813B). This AD requires removing the ground inhibit time delay and the ground test relay from the stall warning and protection system and rewiring part of the stall warning and protection system to assure that system reliance is maintained after relay removal. 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 ground inhibit relay while it is in the energized position caused by the current design, which could result in failure of the stall warning system and possible loss of control of the airplane in certain situations if the crew was not aware that the system had failed.

Final rule

98-21-25 BRITISH AEROSPACE: Amendment 39-10833; Docket No. 98-CE-28-AD.
Applicability: Jetstream Models 3101 and 3201 airplanes, all serial numbers, certificated in any category, that are equipped with the ground inhibit function (Modification JM7813A (SB 27 JM7813A) or JM7813B).

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 failure of the ground inhibit relay while it is in the energized position caused by the current design, which could result in failure of the stall warning system and possible loss of control of the airplane in certain situations if the crew was not aware that the system had failed, accomplish the following:

(a) Remove the ground inhibit time delay and the ground test relay from the stall warning and protection system, and rewire part of the stall warning and protection system to assure that system reliance is maintained after relay removal. Accomplish these actions in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of British Aerospace Jetstream Alert Service Bulletin 27-A-JM7847, Revision 1, dated April 27, 1998.

(b) If the actions of this AD were accomplished in accordance with BritishAerospace Jetstream Alert Service Bulletin 27-A-JM7847, dated December 24, 1997, the affected airplane still needs to be re-tested in accordance with British Aerospace Jetstream Alert Service Bulletin 27-A-JM7847, Revision 1, dated April 27, 1998.

(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 Alert Service Bulletin 27-A-JM7847, Revision 1, dated April 27, 1998, 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 modifications required by this AD shall be done in accordance with British Aerospace Jetstream Alert Service Bulletin 27-A-JM7847, Revision 1, dated April 27, 1998. 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 Alert Service Bulletin 27-A-JM7847, dated December 24, 1997, Revision 1, dated April 27, 1998. This service bulletin is classified as mandatory by the United Kingdom Civil Aviation Authority (CAA).

(g) This amendment becomes effective on November 26, 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 Models 3101 and 3201 airplanes that are equipped with the ground inhibit function (Modification JM7813A (SB 27-JM7813A) or JM7813B) was published in the Federal Register as a notice of proposed rulemaking (NPRM) on April 30, 1998 (63 FR 23686). The NPRM proposed to require removing the ground inhibit time delay and the ground test relay from the stall warning and protection system. The NPRM also proposed to require rewiring part of the stall warning and protection system to assure that system reliance is maintained after relay removal.

Accomplishment of the proposed action as specified in the NPRM would be in accordance with British Aerospace Jetstream Alert Service Bulletin 27-A-JM7847, dated December 24, 1997.

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

After the issuance of the NPRM, British Aerospace corrected the functional test procedures. To incorporate this change, British Aerospace revised Jetstream Alert Service Bulletin 27-A-JM7847 to the Revision 1 level (dated April 27, 1998).

This prompted the FAA to issue 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 Models 3101 and 3201 airplanes that are equipped with the ground inhibit function (Modification JM7813A (SB 27-JM7813A) or JM7813B), which was published in the Federal Register as a supplemental notice of proposed rulemaking on August 11, 1998 (63 FR 42270). The supplemental NPRM proposed to require removing the ground inhibit time delay and the ground test relay from the stall warning and protection system. The supplemental NPRM also proposed to require rewiring part of the stall warning and protection system to assure that system reliance is maintained after relay removal. Accomplishment of the proposed action as specified in the supplemental NPRM would be in accordance with British Aerospace Jetstream Alert Service Bulletin 27-A-JM7847, dated December 24, 1997, Revision 1, dated April 27, 1998.

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.

CostImpact
The FAA estimates that 301 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. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $108,360, 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: