Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that would have required replacement of the retract actuator bracket attachment bolt (RABAB) of the main landing gear (MLG) with a new RABAB, and reidentification of the MLG shock strut. This new action revises the proposed rule by referencing new service information; and by adding an inspection for corrosion, fretting, or other damage of any RABAB installed in accordance with the old service information; and applicable corrective actions. The actions specified by this new proposed AD are intended to prevent failure of the RABAB, which could result in loosening of the actuator bracket and consequent failure of the MLG to retract, with considerable damage to other landing gear parts, including the MLG trunnion fitting. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 25, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-182-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. 2002-NM-182-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, Link”ping, 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 2002-NM-182-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. 2002-NM-182-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on April 15, 2004 (69 FR 19952). That NPRM would have required replacement of the retract actuator bracket attachment bolt (RABAB) of the main landing gear (MLG) with a new RABAB, and reidentification of the MLG shock strut. That NPRM was prompted by reports of failures of the RABAB of the MLG due to hydrogen embrittlement. This can be caused by failure to fully de-embrittle after electroplating the RABAB during manufacture. That condition, if not corrected, could result in loosening of the retract actuator bracket and consequent failure of the MLG to retract, with considerable damage to other landing gear parts, including the MLG trunnion fitting.

Actions Since Issuance of Previous Proposal

Since the issuance of the original NPRM, the Luftfartsverket (LFV), which is the airworthiness authority for Sweden, notified us of reports of failures of RABABs that were replaced in accordance with Saab Service Bulletin 340-32-124, Revision 01, dated May 21, 2002 (which the original NPRM refers to as the acceptable source of service information for replacing the RABAB). Investigation revealed that the service bulletin does not specify the torque value for installing the new RABAB. This condition, if not corrected, could result in improper installation of the RABAB with consequent failure and possible collapse of the MLG.

Explanation of New Relevant Service Information

Saab has issued Saab Service Bulletin 340-32-131, dated June 29, 2004; including as Attachments 1 and 2, APPH Ltd. Service Bulletins AIR83022-32-28 and AIR83064-32-08, both dated January 2002; and as Attachments 3 and 4, APPH Ltd. Service Bulletins AIR83022-32-29 and AIR83064-32-09, both dated April 2002. Saab Service Bulletin 340-32-131 supersedes Saab Service Bulletin 340-32-124, Revision 01, dated May 21, 2002, including as Attachments 1 and 2, APPH Ltd. Service Bulletins AIR83022-32-28 and AIR83064-32-08, both dated January 2002; and Saab Service Bulletin 340-32-125, dated April 29, 2002, including as Attachments 1 and 2, APPH Ltd. Service Bulletins AIR83022-32-29 and AIR83064-32-09, both dated April 2002. Saab Service Bulletin 340-32-131 describes procedures for replacing the RABAB with a new RABAB and reidentifying the MLG strut. If Service Bulletin 340-32-124, Revision 01, has been accomplished previously, Saab Service Bulletin 340-32-131 describes procedures for a one-time visual inspection of the new RABAB for corrosion, fretting, or other damage; and applicable corrective actions. Corrective actions could include replacing the RABAB with a new RABAB and repairing any other damage. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The LFV mandated the service information and issued Swedish airworthiness directive 1-195, dated July 6, 2004, to ensure the continued airworthiness of these airplanes in Sweden.

Comments

Comments were submitted on the original NPRM. Due to the release of new service information, those comments are no longer applicable and are not addressed by this supplemental NPRM.

Conclusion

Since this change expands the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Differences Between the Supplemental NPRM and Service Bulletin

The service bulletin refers to a “visual inspection” of a previously replaced RABAB for corrosion, fretting, or other damage. We have determined that the procedures in the service bulletin should be described as a “detailed inspection.” We have included Note 2 to define this type of inspection.

Cost Impact

We estimate that approximately 281 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 7 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $65 per work hour. Required parts would be supplied at no cost by the manufacturer. Based on these figures, the cost impact of this proposed AD on U.S. operators is estimated to be $127,855, or $455 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.