Airworthiness Directives; Saab Model SAAB 2000 Series Airplanes

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-239-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-239-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Luftfartsverket (LFV), which is the airworthiness authority for Sweden, notified the FAA that an unsafe condition may exist on certain Saab Model SAAB 2000 series airplanes. The LFV advises that it has received reports of excessive leakage of hydraulic fluid from the Number 2 hydraulic system. The cause of such leakage has been attributed to failure of the aluminum end-pieces on the expansion chamber attenuator (ECA) of the standby pump for the Number 2 hydraulic system. This condition, if not corrected, could result in loss of nose wheel steering, flap operation, normal landing gear operation, and reduced redundancy in the brake and flight controls systems.

Explanation of Relevant Service Information

Saab has issued Service Bulletin 2000-29-016, dated April 17, 1998, which describes procedures for replacement of the two end-pieces of the ECA for the standby pump for the Number 2 hydraulic system with new, improved end-pieces constructed of steel. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The LFV classified this service bulletin as mandatory and issued Swedish airworthiness directive (SAD) 1-126, dated April 20, 1998, in order to assure the continued airworthiness of these airplanes in Sweden.

FAA's Conclusions

This airplane model is manufactured in Sweden and is type certificated for operation in the United States under the provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LFV has kept the FAA informed of the situation described above. The FAA has examined the findings of the LFV, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the action specified in the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Information

Operators should note that the referenced service bulletin recommends incorporation of Saab Modification 6096 (reference Saab Service Bulletin 2000-29-015) at the time of accomplishment of the actions described in Saab Service Bulletin 2000-29-016. Saab Modification 6096 is similar to Saab Modification 6132 (reference Saab Service Bulletin 2000-29-016), in that it addresses modification of the end-pieces of the expansion chamber attenuator (ECA) of the Number 3 hydraulic system. However, this proposed AD would not require incorporation of Modification 6096 since modification of the Number 2 hydraulic system adequately addresses the unsafe condition.

Cost Impact

The FAA estimates that 3 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 3 work hours per airplane to accomplish the proposed replacement, and that the average labor rate is $60 per work hour. Required parts would cost approximately $820 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $3,000, or $1,000 per airplane. The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have sufficient

federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 draft regulatory 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, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Saab Aircraft AB: Docket 98-NM-239-AD.

Applicability: Model SAAB 2000 series airplanes, serial numbers -004 through -099 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 (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 leakage of hydraulic fluid from the Number 2 hydraulic system due to failure of the end-pieces of the expansion chamber attenuator (ECA), which could result in loss of nose wheel steering, flap operation, normal landing gear operation, and reduced redundancy in the brake and flight controls systems, accomplish the following: (a) Within 4 months after the effective date of this AD, replace the two end-pieces of the ECA of the standby pump for the Number 2 hydraulic system with new, improved end-pieces constructed of steel, in accordance with Saab Service Bulletin 2000-29-016, dated April 17, 1998. (b) As of the effective date of this AD, no person shall install on any airplane any ECA having P/N 7329114-691. (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, International Branch, ANM-116, 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, International Branch, ANM-116.

Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116. (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.

Note 3: The subject of this AD is addressed in Swedish airworthiness directive (SAD) 1-126, dated April 20, 1998.

Issued in Renton, Washington, on October 5, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-27601 Filed 10-14-98; 8:45 am] BILLING CODE 4910-13-U