Airworthiness Directives; Boeing Model 737-100, -200, -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 currently requires modification of certain fuselage support structure for the number 2 galley. This action would require modification of the same support structure using new methods based on new calculations. This action also would expand the applicability of the existing AD to include additional airplanes. The actions specified by the proposed AD are intended to prevent the galley from shifting, which could limit access to the galley door during emergencies, and result in injury to passengers and flightcrew. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by June 21, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-324-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-324-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 Airplanes, 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:

Keith Ladderud, Aerospace Engineer, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 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-324-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-324-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On January 19, 1995, the FAA issued AD 95-02-08, amendment 39-9127 (60 FR 8295, February 14, 1995), applicable to certain Boeing Model 737 series airplanes, to require modification of certain fuselage support structure for the number 2 galley. That action was prompted by results of engineering tests and analyses which revealed that certain fuselage support structure for the number 2 galley is unable to support certain loads that may occur during emergency landing conditions. If the fuselage support structure breaks, the galley may shift and cause blockage of the forward service door (galley door). The requirements of that AD are intended to prevent inability of passengers and crew to exit the airplane through this door after an emergency landing.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the FAA has determined that the calculations used in the initial release of Boeing Service Bulletin 737-53-1154 were incorrect, and the modification required by that AD was inadequate. Also since issuance of that AD, additional airplanes have been identified that require modification. The actions proposed in this AD are intended to prevent the galley from shifting, which could limit access to the galley door during emergencies, and result in injury to passengers and flightcrew.

Issuance of New Service Information

The FAA has reviewed and approved Boeing Special Attention Service Bulletin 737-53-1154, Revision 1, dated October 3, 2002, which describes various procedures depending on the configuration group to which the airplane belongs.

For airplanes identified in the service bulletin as Group 1, that have a galley operating weight of 995 pounds or less, the service bulletin states that no change is required. For airplanes identified in the service bulletin as Group 1 with a galley operating weight of 996 pounds or greater, the service bulletin advises contacting Boeing for modification instructions.

For airplanes identified in the service bulletin as Group 2, on which the modifications based on the initial release of the service bulletin have been incorporated, the service bulletin advises contacting Boeing for modification instructions.

For airplanes identified as Groups 3 through 9, the service bulletin describes procedures for determining the galley modification requirements by identifying the maximum allowable operating weight of the galley; for identifying the type of intercostal (triangular or rectangular) that is installed at stringer 5R; and for determining if the body station (BS) 360 frame has shear-ties from stringer 3R to stringer 7R. If there are any problems with identifying the modification requirements (e.g., if the existing structure matches the structure applicable to a different configuration group), the service bulletin recommends contacting Boeing.

For airplanes identified in the service bulletin as Groups 3 through 9 that were not modified in accordance with the initial release of the service bulletin, Part I of the Accomplishment Instructions describes the following procedures:

• For Groups 3, 4, and 5: replacing the triangular intercostal with a rectangular intercostal.
• For Groups 3 through 8: installing a shear-tie kit, and installing a stringer clip kit.
• Groups 3 through 9: installing a radius strap kit.

For airplanes identified in the service bulletin as Groups 3 through 8 that were modified in accordance with the initial release of the service bulletin; Part II of the Accomplishment Instructions in the service bulletin describes the following procedures:

• Inspecting to verify that the shear-ties are attached to the BS 360 frame, retrofitting, or contacting Boeing for instructions; as applicable.
• Installing a supplemental parts kit on the rectangular intercostal; installing a radius strap kit; and contacting Boeing if a kit cannot be installed.

Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

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 95-02-08 to continue to require modification of certain fuselage support structure for the number 2 galley. This new action would require modification of the same fuselage support structure using different modification methods based on new calculations. This new action would also apply to additional airplanes that were delivered with a single number 2 galley support intercostal at stringer 5R. The actions would be required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

Difference Between the Proposed AD and the Service Bulletin

Although the service bulletin specifies that operators may contact the manufacturer for disposition of certain modifications, this proposed AD would require operators to make modifications per a method approved by the FAA, or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings.

Explanation of Change in Applicability

Additional airplanes are included in the applicability of the proposed AD that were not included in AD 95-02-08. The additional airplanes are included in the proposed AD because airplanes of a certain configuration were not included in the original issue of the service bulletin, and this configuration requires modification.

Clarification of Compliance Time

The service bulletin specifies doing the actions at the next maintenance check. Because maintenance schedules vary among operators, this proposed AD would require accomplishment of the actions within 18 months after the effective date of the proposed AD. We find that 18 months is within an interval of time that parallels normal scheduled maintenance for most affected operators and is appropriate for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 583 airplanes of the affected design in the worldwide fleet. The FAA estimates that 170 airplanes of U.S. registry would be affected by this proposed AD.

The new actions that are proposed in this AD would take between 8 and 22 work hours per airplane to accomplish, depending on the airplane's configuration. The average labor rate is $65 per work hour. Required parts would cost between $5,200 and $23,790 per airplane, depending on the airplane's configuration. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be between $5,720 and $25,220 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.