AD 97-02-05

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Jetstream Model 4101 airplanes, that currently requires, among other things, replacing certain yaw damper servos in the autopilot system, or rendering the servo inoperative. The actions specified by that AD are intended to prevent overheat failure of the Flight Control Computer (FCC), which could result in smoke in the flight deck that could inhibit the ability of the flightcrew to safely operate and land the airplane. This new amendment requires installation of circuit breakers on the avionics relay panel, which, when accomplished, constitutes terminating action for the previous requirements of the AD.

Final rule

97-02-05 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9889. Docket 96-NM-243-AD. Supersedes AD 96-19-06, Amendment 39-9754.
Applicability: Model 4101 airplanes having serial numbers 41004 through 41092, inclusive; on which Jetstream Service Bulletin J41-22-006, dated July 1, 1996 (Kit JK42867), has not been accomplished; certificated in any category.

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 (c) 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 as indicated, unless accomplished previously.

To prevent overheat failure of the Flight Control Computer (FCC), which could result in smoke in the flight deck that could inhibit the ability of the flightcrew to safely operate and land the airplane, accomplish the following:

(a) Within 14 days after October 1, 1996 (the effective date of AD 96-19-06), perform a one- time inspection of the airplane records to determine the serial number, the total number of hours time-in-service accumulated, and the date of installation of the yaw damper servo in the autopilot system; and to determine the date of installation of Kit JK42716 (reference Jetstream Service Bulletin J41-53-016 or J41-22-007), if installed. Accomplish the inspection in accordance with Part 1 of the Accomplishment Instructions of Jetstream Alert Service Bulletin J41-A22-005, dated July 1, 1996.Thereafter, either remove and replace the yaw damper servo and install Kit JK42716 (if not installed previously), or render the yaw damper servo inoperative, in accordance with Part 2 or 3 of the alert service bulletin, respectively, at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable.

(1) If Kit JK42716 has not been installed: Prior to the accumulation of 1,000 hours total time-in-service on the yaw damper servo, or within 30 days after October 1, 1996, whichever occurs later.

(2) If Kit JK42716 has been installed and the yaw damper servo was installed prior to the installation of Kit JK42716: Prior to the accumulation of 1,000 hours total time-in-service on the yaw damper servo, or within 30 days after October 1, 1996, whichever occurs later.

(3) If Kit JK42716 has been installed and the yaw damper servo was installed after the installation of Kit JK42716: Prior to the accumulation of 3,000 total hours time-in-service on the yaw damper servo, or within 30 days after October 1, 1996, whichever occurs later.

(b) Within 90 days after the effective date of this AD, install circuit breakers on the avionics relay panel (Kit JK42867) in accordance with Jetstream Service Bulletin J41-22-006, dated July 1, 1996. Accomplishment of this installation constitutes terminating action for the requirements of paragraph (a) of this AD.

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(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) The actions shall be done in accordance with Jetstream Alert Service Bulletin J41-A22- 005, dated July 1, 1996; and Jetstream Service Bulletin J41-22-006, dated July 1, 1996. The incorporation by reference of Jetstream Alert Service Bulletin J41-A22-005, dated July 1, 1996, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of October 1, 1996 (61 FR 48614, September 16, 1996). The incorporation by reference of Jetstream Service Bulletin J41-22-006, dated July 1, 1996, 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, Inc., P.O. Box 16029, Dulles International Airport, Washington, DC 20041-6029. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment becomes effective on February 27, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 96-19-06, amendment 39-9754 (61 FR 48614, September 16, 1996), which is applicable to certain Jetstream Model 4101 airplanes, was published in the Federal Register on October 23, 1996 (61 FR 54967). The action proposed to supersede AD 96-19-06 to continue to require the actions currently specified in that AD:

1. a one-time inspection of the airplane records to determine:

- the serial number,

- the total number of hours time-in-service accumulated,

- the date of installation of the yaw damper servo in the autopilot system; and

- the date of installation of a particular kit, if installed.

2. removal and replacement of certain yaw damper servos, or rendering the yaw damper servo inoperative.

The action also proposed to add a requirement to install circuit breakers on the avionics relay panel. When accomplished, thisinstallation would constitute terminating action for the previous requirements of the AD.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed. Cost Impact

There are approximately 55 Jetstream Model 4101 airplanes of U.S. registry that will be affected by this AD.

The actions that are currently required by AD 96-19-06 take approximately 2 to 5 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the previously required actions on U.S. operators is estimated to be between $6,600 and $16,500, or between $120 and $300 per airplane.

The new action (installation of circuit breakers) that is required by this new AD will take approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact of the installation requirement of this AD on U.S. operators is estimated to be $9,900, or $180 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. 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 towarrant 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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 (14CFR 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 removing amendment 39-9754 (61 FR 48614, September 16, 1996), and by adding a new airworthiness directive (AD), amendment 39-9889, to read as follows: