AD 94-20-12

This amendment adopts a new airworthiness directive (AD), applicable to certain IAI Model 1125 Westwind Astra airplanes, that requires relocation of the ground cable in the slat power drive unit. This amendment is prompted by a report that the drive system for the leading edge slat stopped in transit during flight on a Model 1125 Westwind Astra airplane. This incident was caused by an improper ground connection for the electric motor of the slat drive system, which resulted in arcing and an open electrical circuit. The actions specified by this AD are intended to prevent possible fuel vapor fire due to electrical arcing in an area where fuel vapors might be present and the inability to move the slats during flight due to an open electrical circuit.

Final rule

94-20-12 ISRAEL AIRCRAFT INDUSTRIES LIMITED: Amendment 39-9041. Docket 94-NM- 39-AD.
Applicability: Model 1125 Westwind Astra airplanes; serial numbers 004 through 066 inclusive, and 068; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent possible fuel vapor fire due to electrical arcing in an area where fuel vapors might be present and the inability to move the slats during flight due to an open electrical circuit, accomplish the following:

(a) Within 50 hours time-in-service after the effective date of this AD, relocate the ground cable in the slat power drive unit in accordance with Astra Jet Service Bulletin SB 1125-27-110, Revision 1, dated February 16, 1994.

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

(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) The relocation shall be done in accordance with Astra Jet Service Bulletin SB 1125-27- 110, Revision 1, dated February 16, 1994, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-3, 5
1
February 16, 1994
4
Original
January 19, 1994
This incorporation by reference was approved by the Director of the FederalRegister in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Astra Jet Corporation, Technical Publications, 77 McCullough Drive, Suite 11, New Castle, Delaware 19720-9813. 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.

(e) This amendment becomes effective on November 14, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Israel Aircraft Industries (IAI) Model 1125 Westwind Astra airplanes was published in the Federal Register on May 5, 1994 (59 FR 23174). That action proposed to require relocation of the ground cable in the slat power drive unit.

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

The FAA estimates that 52 airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will costapproximately $53 per airplane. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $11,336, or $218 per airplane.

The total cost impact figure discussed above is 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.

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

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: