AD 96-20-06

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Jetstream Model 4101 airplanes, that currently requires inspection to determine the number of hours time-in-service on the landing gear control unit, and modification of the cable (electrical wiring circuit) of the landing gear control unit. That AD was prompted by a report of failure of a micro-switch in the landing gear control unit. This amendment requires installation of a new landing gear control unit. This amendment also expands the applicability of the existing AD to include additional airplanes. The actions specified by this AD are intended to prevent uncommanded retraction of a landing gear, which could adversely affect airplane controllability.

Final rule

96-20-06 JETSTREAM AIRCRAFT LIMITED: Amendment 39-9772. Docket 96-NM-49-AD. Supersedes AD 95-09-03, Amendment 39-9241.
Applicability: Model 4101 airplanes, constructor numbers 41001 through 41073 inclusive; 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 (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 as indicated, unless accomplished previously.

To prevent uncommanded retraction of the landing gear, which can adversely affect airplane controllability, accomplish the following:

(a) For airplanes having constructor numbers 41001 through 41046 inclusive, and 41048 through 41052 inclusive; equipped with either landing gear control unit part number 717701-1 or 717701-1 Mod A: Within 8 hours time-in-service after June 14, 1995 (the effective date of AD 95-09-03, amendment 39-9241), perform an inspection to determine the number of hours time-in- service on the landing gear control unit, in accordance with Jetstream Alert Service Bulletin J41- A32-042, dated April 13, 1995.

(1) For those airplanes on which the control unit has accumulated less than 200 hours time-in-service: Prior to further flight, modify the cable (electrical wiring circuit) of the landing gear control unit in accordance with the alert service bulletin.

(2) For those airplanes on whichthe control unit has accumulated 200 hours or more time-in-service: Within 50 hours time-in-service or within 7 days after June 14, 1995 (the effective date of AD 95-09-03, amendment 39-9241), whichever occurs earlier, modify the cable (electrical wiring circuit) of the landing gear control unit in accordance with the alert service bulletin.

(b) For airplanes having constructor numbers 41001 through 41073 inclusive: Within 6 months after the effective date of this AD, install a new improved landing gear control unit and modify the wiring, in accordance with Jetstream Service Bulletin J41-32-044, dated September 22, 1995.

(c) As of the effective date of this AD, no person shall install a landing gear control unit having part number 717701-1 or 717701-1 Mod A, on any airplane.

(d) 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.

(e) 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.

(f) The inspection and modification shall be done in accordance with Jetstream Alert Service Bulletin J41-A32-042, dated April 13, 1995. The installation shall be done in accordance with Jetstream Service Bulletin J41-32-044, dated September 22, 1995. The incorporation by reference of Jetstream Alert Service Bulletin J41-A32-042, dated April 13,1995, 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 June 14, 1995 (60 FR 28035, May 30, 1995). The incorporation by reference of Jetstream Service Bulletin J41-32-044, dated September 22, 1995, 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.

(g) This amendment becomes effective on November 4, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-09-03, amendment 39-9241 (60 FR 28035, May 30, 1995), which is applicable to certain Jetstream Model 4101 airplanes, was published in the Federal Register on April 29, 1996 (61 FR 18707). The action proposed to supersede AD 95-09-03. For those airplanes subject to AD 95-09-03, it proposed to continue to require an inspection to determine the number of hours time-in-service on the landing gear control unit, and modification of the cable (electrical wiring circuit) of the landing gear control unit. For those airplanes and certain others, it proposed to require installation of a new improved landing gear control unit.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. Support for the Proposed Rule

One commenter supports the proposed rule.Request to Limit Applicability of Proposed Rule

One commenter questions why the proposed rule requires Jetstream Modification JM41490 (modification of the cable of the landing gear control unit) to be accomplished on the additional airplanes that have been included in the applicability of the proposed rule. The commenter states that this modification was installed on airplanes having constructor numbers 41052 and subsequent at the manufacturer's facility prior to delivery. Therefore, those airplanes should not be subject to the requirement for that modification.

The FAA points out that Modification JM41490 (which is described in Jetstream Alert Service Bulletin J41-A32-042) is required by AD 95-09-03 to be accomplished on Model 4101 airplanes having constructor numbers 41001 through 41046 inclusive, and 41048 through 41052 inclusive. That requirement is specified in paragraph (a) of AD 95-09-03. Paragraph (a) of this new AD merely restates the requirements of paragraph (a) of AD 95-09-03. It clearly indicates that it is applicable only to those same airplanes that were subject to AD 95-09-03; no new, additional airplanes are subject to the requirements of that paragraph. Further, airplanes on which those actions have been performed previously, do not have to be modified in accordance with that paragraph a second time. Request to Verify Parts Availability

One commenter states that it has information that the manufacturer has been unable to produce the landing gear control units at the originally planned rate. The commenter requests that the FAA verify with the manufacturer that the landing gear control units required by paragraph (b) of the proposed rule will be available for installation within the proposed compliance time of six months.

The FAA has verified with the manufacturer that there should be no delay in the manufacturing of those parts. Therefore, the compliance time of six months for this AD will remain unchanged. ConclusionAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. Cost Impact

There are approximately 44 Jetstream Model 4101 airplanes of U.S. registry that will be affected by this AD.

The actions that are currently required by AD 95-09-03, and retained in this AD, take approximately 7 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. The required parts are provided by the manufacturer at no cost to the operator. Based on these figures, the cost impact on U.S. operators of the actions currently required is estimated to be $18,480, or $420 per airplane. The FAA has been advised that all affected U.S. operators have accomplished these requirements; therefore, there is no future cost impact of these requirements on current U.S. operators of these airplanes.

The new installation that is required by this new AD will take approximately 6 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would be provided at no cost to the operator. Based on these figures, the cost impact on U.S. operators of the new requirements of this AD is estimated to be $15,840, or $360 per airplane. This cost impact figure is based on assumptions that no operator has yet accomplished this requirement of this AD action, and that no operator would accomplish that action 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 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 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 (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 removing amendment 39-9241 (60 FR 28035, May 30, 1995), and by adding a new airworthiness directive (AD), amendment 39-9772, to read as follows: