Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737 series airplanes. That AD currently requires a one-time general visual inspection of the seat locks and seat tracks of the flightcrew seats to ensure that the seats lock in position and to verify that lock nuts and bolts of adequate length are installed on the rear track lock bracket, and corrective action, if necessary. This action would revise the applicability of the existing AD by adding airplanes. The actions specified by the proposed AD are intended to prevent uncommanded movement of the flightcrew seats during acceleration and take-off of the airplane, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 20, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-174-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-174-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Shannon Lennon, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 917-6435; fax (425) 917-6590.

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-174-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-174-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 18, 2000, the FAA issued AD 2000-10-21, amendment 39-11745 (65 FR 34063, May 26, 2000), applicable to certain Boeing Model 737 airplanes, to require a one-time general visual inspection of the seat locks and seat tracks of the flightcrew seats to ensure that the seats lock in position and to verify that lock nuts and bolts of adequate length are installed on the rear track lock bracket, and corrective action, if necessary. That action was prompted by reports indicating instances of the pilot seat sliding to the aft-most position during acceleration and take-off on certain Boeing Model 737 series airplanes. The requirements of that AD are intended to prevent uncommanded movement of the flightcrew seats during acceleration and take-off of the airplane, which could result in reduced controllability of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the airplane manufacturer has informed the FAA that additional airplanes may be equipped with IPECO flightcrew seats that are subject to the identified unsafe condition. Those seats may have been installed on airplanes out of operators' stock or from an airplane not yet modified per AD 2000-10-21, amendment 39-11745.

Explanation of Relevant Service Information

We have reviewed and approved Boeing Alert Service Bulletin 737-25A1363, Revision 1, dated March 28, 2002, which revises the effectivity of the initial release (which was referenced as the appropriate source of service information for the actions required by AD 2000-10-21) of the service bulletin by adding additional airplanes. The procedures for a one-time general visual inspection and corrective actions if necessary specified in Revision 1 are essentially identical to those described in the initial release of the service bulletin. No more work is necessary on airplanes changed per the initial release of this service bulletin. Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition.

Boeing Alert Service Bulletin 737-25A1363, Revision 1, dated March 28, 2002, refers to IPECO Service Bulletin A001-25-47, dated January 13, 1992, as an additional source of service information for accomplishment of the inspection of the seat locks and seat tracks of the flightcrew seats and corrective action, if necessary.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 2000-10-21 to continue to require a one-time general visual inspection of the seat locks and seat tracks of the flightcrew seats to ensure that the seats lock in position and to verify that lock nuts and bolts of adequate length are installed on the rear track lock bracket, and corrective action, if necessary. The proposed AD would also revise the applicability of the existing AD by adding airplanes. The actions would be required to be accomplished in accordance with the Boeing alert service bulletin described previously, except as discussed below.

Difference Between Service Bulletin and Proposed AD

Operators should note that, although the Boeing alert service bulletin does not recommend a compliance time for accomplishment of the described actions, the FAA has determined that a 90-day compliance time would address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this proposed AD, we considered the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the actions. In light of all of these factors, we find a 90-day compliance time for completion of the actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Explanation of Change Made to Existing Requirements

For clarification, we have revised the definition of a “general visual inspection” in this proposed AD.

Cost Impact

There are approximately 1,385 airplanes of the affected design in the worldwide fleet. The FAA estimates that 282 airplanes of U.S. registry would be affected by this proposed AD.

For Group 1 airplanes listed in Boeing Alert Service Bulletin 737-25A1363, Revision 1: The actions that are currently required by AD 2000-10-21 take approximately 3 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $195 per airplane.

For Group 2 airplanes listed in Boeing Alert Service Bulletin 737-25A1363, Revision 1: The new actions that are proposed in this AD action would take approximately 3 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $195 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or 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.