04-4940. Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes. This proposal would require replacement of certain hydraulic hoses with new hydraulic hoses. This action is necessary to prevent cracking and/or rupture and subsequent failure of hydraulic hoses. Such failure could result in loss of hydraulic pressure and fluid quantity, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by April 5, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-278-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-278-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linköping, Sweden. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Rosanne Ryburn, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

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 action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-278-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. 2003-NM-278-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 SF340A and SAAB 340B series airplanes. The LFV advises that a large number of hydraulic hoses have failed due to fatigue caused by exposure of the hoses to both high pressure and bending cycles. Such failure could result in loss of hydraulic pressure and fluid quantity, and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

Saab has issued Service Bulletin 340-29-022, Revision 01, dated February 20, 2003, which describes procedures for removal of the existing hydraulic hoses leading to the actuators for the flaps, main landing gear (MLG), nose landing gear (NLG), NLG wheel well, and NLG downlock; identification of the new hydraulic hoses, and subsequent installation (including torquing the coupling nuts). Identification of new hydraulic hoses includes using a Vibro-pen to engrave the year, month, and date of the hose installation, and the serial number of the airplane on which the hose was installed. New hydraulic hoses installed in the flap actuators and MLG actuators must also be identified with the letters RF for the right-side flap actuator, LF for the left-side actuator, RG for the right-side MLG actuator, and LG for the left-side MLG actuator. 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 1-170, dated December 17, 2001, to ensure the continued airworthiness of these airplanes in Sweden.

FAA's Conclusions

These airplane models are manufactured in Sweden and are type certificated for operation in the United States under the provisions of section 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 AD

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 actions specified in the service bulletin described previously.

Cost Impact

We estimate that 308 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 5 work hours per airplane to accomplish the proposed replacement of the hydraulic hoses, and that the average labor rate is $65 per work hour. Required parts would cost approximately $1,600 per airplane. Based on these figures, the cost impact of the proposed replacement of the hydraulic hoses on U.S. operators is estimated to be $592,900, or $1,925 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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.

§ 39.13

[Amended]

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

Saab Aircraft AB: Docket 2003-NM-278-AD.

Applicability: Model SAAB SF340A series airplanes having serial numbers 004 through 159 inclusive, and SAAB 340B series airplanes having serial numbers 160 through 459 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent cracking and/or rupture and subsequent failure of hydraulic hoses, which could result in loss of hydraulic pressure and fluid quantity, and consequent reduced controllability of the airplane, accomplish the following:

Replacement of Hydraulic Hoses

(a) Replace the hydraulic hoses leading to the actuators of the flaps, main landing gear (MLG), nose landing gear (NLG), NLG downlock, and NLG wheel well, with new hydraulic hoses by doing all of the actions per the Accomplishment Instructions of Saab Service Bulletin 340-29-022, Revision 01, dated February 20, 2003. Do the replacement at the times specified in paragraphs (a)(1) and (a)(2) of this AD, as applicable.

(1) For airplanes on which affected hydraulic hoses have accumulated 12,000 or more total flight cycles since new: Within the next 5,000 flight cycles or 24 months after the effective date of this AD, whichever is first.

(2) For airplanes on which affected hydraulic hoses have accumulated less than 12,000 total flight cycles since new: Before the accumulation of 12,000 total flight cycles or within 24 months after the effective date of this AD, whichever is later.

Alternative Methods of Compliance

(b) In accordance with 14 CFR 39.19, the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, is authorized to approve alternative methods of compliance for this AD.

Note 1:

The subject of this AD is addressed in Swedish airworthiness directive 1-170, dated December 17, 2001.

Issued in Renton, Washington, on February 24, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.