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 inspection of the main landing gear's (MLG) separation bolt harness, corrective actions if necessary, and replacement of the MLG's separation bolt harness. For certain airplanes, this proposal would also require modification of the MLG separation bolt's electrical harness. These actions are necessary to prevent failure of the MLG to extend during use of the emergency backup system. These actions are intended to address the identified unsafe condition.

DATES:

Comments must be received by May 3, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-17-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-17-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:

Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2125; fax (425) 227-1149.

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-17-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-17-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

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. LFV advises that it has received a number of reports of broken wires and corroded connectors in the harness for the separation bolt. The cause has been attributed to repairs and installations that have not been accomplished in accordance with the type design. If the system harness is incorrectly installed or repaired, the function of the separation bolt will be inhibited, and consequently the emergency system for landing gear extension will not be fully available. This condition, if not corrected, could result in failure of the main landing gear to extend during use of the emergency backup system.

Explanation of Relevant Service Information

Saab has issued Service Bulletin 340-32-127, dated December 18, 2002; and Revision 01, dated January 23, 2003, which describes procedures for inspection of the MLG's separation bolt harness, and corrective actions, if necessary. The corrective actions involve modifications to the separation bolt harness's wires, clamps, convolex tube, and shrinkable tube, as applicable. Saab has also issued Service Bulletin 340-32-128, dated March 28, 2003, which describes procedures for replacement of the separation bolt harness of the MLGs with a new improved harness.

For certain airplanes, Saab Service Bulletin 340-32-128 recommends prior or concurrent accomplishment of the Accomplishment Instructions of Saab Service Bulletin 340-32-041, Revision 1, dated October 9, 1987. The Accomplishment Instructions describe procedures for modification of the separation bolt harness. The modification includes the lengthening of the existing electrical harness for the explosive bolt with a new, improved electrical harness, and the rerouting and securing of the existing harness.

For certain airplanes, Saab Service Bulletin 340-32-041 recommends prior or concurrent accomplishment of the Accomplishment Instructions of Saab Service Bulletin 340-32-028, Revision 01, dated November 25, 1986. The Accomplishment Instructions describe procedures for modification of the separation bolt harness. The modification includes adding a shrink sleeve to the separation bolt squib electrical connectors, and re-routing the separation bolt ground wires at the wheel well structure.

Accomplishment of the actions specified in these service bulletins is intended to adequately address the identified unsafe condition. LFV classified these service bulletins as mandatory and issued Swedish airworthiness directives 1-186, dated December 20, 2002, and 1-189, dated April 1, 2003, to ensure 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 section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, LFV has kept the FAA informed of the situation described above. The FAA has examined the findings of 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 actions specified in the service bulletins described previously.

Cost Impact

The FAA estimates that 224 airplanes of U.S. registry would be affected by this proposed AD. The following table shows the estimated cost impact for airplanes affected by this AD. The average labor rate is $65 per work hour.

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.