AD 94-24-01

This amendment supersedes Airworthiness Directive (AD) 87-04-04 and AD 89-16-02, which currently require the following on Jetstream Aircraft Limited (JAL) HP 137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes: repetitively inspecting the universal joints and universal rivets, replacing any damaged part, and limiting the in-service life of the torque tube shaft assembly. JAL has introduced an improved flap torque tube shaft assembly that includes universal joints that are not life limited. The Federal Aviation Administration's policy on aging commuter-class aircraft is to eliminate or, in certain instances, reduce the number of certain repetitive short-interval inspections when improved parts or modifications are available. This action requires installing this improved flap torque shaft assembly in place of the repetitive inspection and life limit requirements of the two existing AD's. The actions specified by this AD are intended to prevent failure of the flap torque assembly, which could result in asymmetric flap deployment and loss of control of the airplane.

Final rule

94-24-01 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9074; Docket No. 94-CE- 02-AD. Supersedes AD 87-04-04, Amendment 39-5529, and AD 89-16-02, Amendment 39- 6273.
Applicability: HP 137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 airplanes (all serial numbers), certificated in any category.

Compliance: Required within the next 50 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

To prevent failure of the flap torque shaft assembly, which could result in asymmetric flap deployment and loss of control of the airplane, accomplish the following:

NOTE 1: The effective date of this AD is more than 12 months after the issue date of this AD. This will allow operators time to schedule the flap torque shaft assembly replacement. The requirements of AD 87-04-04 and AD 89-16-02 will apply until the effective date of this AD or until the installation or modification specified by paragraph (a) of this AD is accomplished, whichever occurs first.

(a) Install an improved torque shaft assembly in accordance with Part 1 of the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Aircraft Limited Service Bulletin (SB) No. 27-JA 920340; or modify the existing torque shaft assembly in accordance with Part 2 of the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Aircraft Limited SB No. 27- JA 920340, which incorporates the following pages:

Pages
Revision Level
Date
1 through 6
and 9 through 16
2
December 21, 1993
7, 8, and 17
through 28
Original Issue
September 2, 1992

(b) The life limit requirements of the torque tube shaft assembly required by AD 87- 04-04, and the repetitive inspections of the universal joints and universal joint rivets required by AD 89-16-02 remain mandatory until the effective date of this AD or upon accomplishing the installation or modification referenced by paragraph (a) of this AD, whichever occurs first.

(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, Brussels Aircraft Certification Office (ACO), Europe, Africa, Middle East office, FAA, c/o American Embassy, 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Brussels ACO.

(e) The installation or modification required by this AD shall be done in accordance with Jetstream Service Bulletin No. 27-JA 920340:

Pages
Revision Level
Date
1 through 6
and 9 through 16
2
December 21, 1993
7, 8, and 17
through 28
Original Issue
September 2, 1992

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 Jetstream 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. 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.

(f) This amendment (39-9074) supersedes both AD 87-04-04, Amendment 39-5529, and AD 89-16-02, Amendment 39-6273.

(g) This amendment becomes effective on December 1, 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 HP 137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes was published in the Federal Register on July 12, 1994 (59 FR 35490). The action proposed to supersede both AD 87-04-04 and AD 89-16-02 with a new AD that would require installing this improved flap torque shaft assembly in place of the repetitive inspection and life limit requirements of the two existing AD's. The proposed actions would be accomplished in accordance with Jetstream Aircraft Limited Service Bulletin No. 27-JA 920340.

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, the FAA has determined that air safety and the public interestrequire 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 nor add any additional burden upon the public than was already proposed.

This action is based on the FAA's aging commuter-class aircraft policy. This policy simply states that airplane owners/operators should incorporate a known design change when it could eliminate, or, in certain instances, reduce the number of critical repetitive inspections.

This final rule action has an effective date of approximately 12 months after publication in the Federal Register and a compliance time of 50 hours time-in-service after the effective date. This will allow operators time to schedule the flap torque shaft assembly replacement. The requirements of AD 87-04-04 and AD 89-16-02 will still apply until the effective date of this AD or until the installation or modification required by this AD is accomplished, whichever occurs first.

The FAA estimates that 245 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 31 workhours per airplane to accomplish the required action, and that the average labor rate is approximately $55 an hour. Parts cost approximately $1,010 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $665,175. This figure is based on the assumption that no affected airplane operator has accomplished the required actions. In addition, this action eliminates the need for the repetitive inspections required by AD 87-04-04 and AD 89-16-02. The FAA has no way of determining the operation levels of each individual operator of the affected airplanes, and subsequently cannot determine the repetitive inspection costs that will be eliminated by the required action. The FAA estimates these costs to be substantial over the long-term.

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 both AD 87-04-04, Amendment 39-5529, and AD 89-16-02, Amendment 39-6273, and by adding a new airworthiness directive to read as follows: