AD 95-11-17

This amendment supersedes Airworthiness Directive (AD) 90-13-12, which currently requires modifying the airplane electrical system and revising the emergency procedures section of the Airplane Flight Manual (AFM) on certain Jetstream Aircraft Limited (JAL) Jetstream Models 3101 and 3201 airplanes. This action retains the requirements of AD 90-13-12 for those airplanes that do not have modified inverters installed and the inverted transfer function restored. The Federal Aviation Administration (FAA) has determined that installing modified inverters along with restoring the inverter transfer function corrects the problems in the power supply addressed by AD 90-13-12. The actions specified by this AD are intended to prevent alternating current system failures, which, if not detected and corrected, could result in damage to the airplane navigational systems.

Final rule

95-11-17 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9250; Docket No. 90-CE- 67-AD. Supersedes AD 90-13-12, Amendment 39-6629.
Applicability: Jetstream Models 3101 and 3201 airplanes (serial numbers 697 through 904), certificated in any category, that do not have the following:

1. Two modified inverters, part number (P/N) 1B350-1B1-3, installed in accordance with the instructions in Jetstream Service Bulletin (SB) 24-JM 7740, dated November 15, 1990; and

2. The inverter transfer function restored in accordance with the instructions in Jetstream SB 24-JA 900941, dated November 14, 1990; or Jetstream SB 24-JA 900941, Revision 1, dated February 18, 1992.

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 use the authority provided in paragraph (e) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless already accomplished (compliance with superseded AD 90-13-12).

To prevent alternating current system failures, which, if not detected and corrected, could result in damage to the airplane navigational systems, accomplish the following:

(a) Within the next 50 hours time-in-service (TIS) after the effective date of this AD, modify the airplane electricalsystem and revise the emergency procedures section of the airplane flight manual in accordance with the instructions in Jetstream Alert Service Bulletin (ASB) 24-A- JA 900443, Revision 2, dated November 15, 1990, Section 2, ACCOMPLISHMENT INSTRUCTIONS; and APPENDIX C.

(b) Within the next 100 hours TIS after the effective date of this AD, modify the airplane electrical system in accordance with the instructions in Jetstream ASB 24-A-JM 7708, Revision 1, dated May 22, 1990, and revise the emergency procedures section of the airplane flight manual in accordance with the instructions in Jetstream ASB 24-A-JA 900443, Revision 2, dated November 15, 1990, APPENDIX C; or the following Advance Amendment Bulletins (AAB), as applicable:

Model
Publication
3101
AFM HP.4.10, Jetstream AAB number 6 with at least issue 1 status; and AFM HP.4.10, Jetstream AAB number 4 with at least issue 2 status
3201

AFM HP.4.16, Jetstream AAB number 2 with at least issue 2 status, and removal ofJetstream AAB number 2, issue 1

NOTE 2: Compliance with a previous revision level of the service information referenced in this AD fulfills the applicable requirements of this AD and is considered "unless already accomplished" for that portion of the AD.

(c) Replacement of both inverters, P/N 1B350-1B1-2, with modified inverters P/N 1B350-1B1-3 in accordance with the "ACCOMPLISHMENT INSTRUCTIONS" section of Jetstream SB 24-JM 7740, dated November 15, 1990, and restoration of the inverter transfer function in accordance with Jetstream ASB 24-JA 900941, dated November 14, 1990; or Jetstream ASB 24-JA 900941, Revision 1, dated February 18, 1992, is considered terminating action for the requirements of this AD.

(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 times that provides an equivalent level of safety may be approved by the Manager, Brussels Aircraft Certification Office ACO, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, B-1000 Brussels, Belgium. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Brussels ACO.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Brussels ACO.

(f) The modifications required by this AD shall be done in accordance with Jetstream Alert Service Bulletin 24-A-JA 900443, Revision 2, dated November 15, 1990, and Jetstream Alert Service Bulletin 24-A-JM 7708, Revision 1, dated May 22, 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 fromJetstream Aircraft Limited, Manager Product Support, Prestwick Airport, Ayrshire, KA9 2RW Scotland; or Jetstream Aircraft Inc., Librarian, P.O. Box 16029, Dulles International Airport, Washington, DC, 20041-6029. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief 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.

(g) This amendment (39-9250) supersedes AD 90-13-12, Amendment 39-6629.

(h) This amendment becomes effective on July 19, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain JAL Models 3101 and 3201 airplanes was published in the Federal Register on February 10, 1995 (60 FR 7922). The action proposed to supersede AD 90-13-12 with a new AD that would (1) retain the requirements of modifying the airplane electrical system and revising the emergency procedures section of the AFM required by AD 90-13-12; and (2) require these modification and revisions only for those airplanes that do not have modified inverters, P/N 1B350-1B1-3, installed in accordance with the instructions in Jetstream Service Bulletin (SB) 24-JM 7740, dated November 15, 1990, and do not have the inverter transfer function restored in accordance with the instructions in Jetstream SB 24-JA 900941, dated November 14, 1990; or Jetstream SB 24-JA 900941, Revision 1, dated February 18, 1992. Accomplishment of the proposed airplane electricalmodifications would be in accordance with Jetstream Alert Service Bulletin (ASB) 24-A-JA 900443, Revision 1, dated May 1, 1990; and Jetstream ASB 24-A-JM 7708, Revision 1, dated May 22, 1990.

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.

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.

The FAA estimates that 180 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 10 workhours per airplane to accomplish the required 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 $108,000. This figure is based on the assumption that no affected owner/operator has accomplished the required modification.

Since AD 90-13-12, which this AD supersedes, requires the same actions (except for a limit in the airplane applicability), there is no additional cost of this AD on U.S. operators. The $28,800 cost difference between this AD (estimated $108,000) and superseded AD 90-04-04 (estimated $79,200) is a result of inflationary costs used in determining the costs of labor ($60 per hour as opposed to $40 per hour).

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

Section 39.13 - [AMENDED]
2. Section 39.13 is amended by removing AD 90-13-12, Amendment 39-6629 (55 FR 23890, June 13, 1990), and adding a new AD to read as follows: