01-17121. Airworthiness Directives; Boeing Model 737-600, -700, -700C, and -800 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737-600, -700, -700C, and -800 series airplanes. This action prohibits installation of repairs of the elevator tab using previously approved repair procedures. This action is necessary to prevent installation of repairs of the elevator tab that are outside allowable limits, which could result in excessive in-flight vibrations of the elevator tab, and consequent loss of controllability of the airplane.

DATES:

Effective July 26, 2001.

Comments for inclusion in the Rules Docket must be received on or before September 10, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-188-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. 2001-NM-188-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 for Windows or ASCII text.

The service information referenced in this AD 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 98055-4056.

FOR FURTHER INFORMATION CONTACT:

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA has received numerous reports of in-flight vibrations of the elevator tab on Model 737-600, -700, and -800 (“Next Generation”) series airplanes. These vibrations have been attributed to loose or missing components of the elevator tab assemblies, excessive wear of the elevator tab, excessive tab freeplay, and/or tab weight and center of gravity changes.

In addition, we have determined that repairs of the elevator tab done using certain procedures approved before the effective date of this AD can adversely affect the weight and center of gravity of the elevator tab. Such changes in the tab weight and center of gravity can cause excessive in-flight vibration of the elevator tab. Therefore, updated limitations on repair procedures are necessary to ensure the reliability of the elevator tab in flight. Continued operation of these airplanes in such conditions could result in excessive in-flight vibrations of the elevator tab, and consequent loss of controllability of the airplane.

Explanation of Service Information

The FAA has reviewed Boeing All Operator Message M-7200-01-00756, Revision 1, dated May 29, 2001, which describes allowable repair limits for the elevator tab. Repair limits include, but are not limited to, the following:

• Repair can only be one facesheet (upper or lower skin) and honeycomb core in depth.
• Repair of damaged honeycomb core by potting is not permitted.
• Maximum size of damage (allowable damage) that may be sealed using aluminum foil tape is 1 inch in diameter.
• Maximum damage size that could be repaired using 150 degree or 200 degree wet layup is .5 inch across the largest dimension.
• No 250 degree prepreg repairs are permitted.

Explanation of the Requirements of the Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent installation of repairs that are outside allowable limits of the elevator tab, which could result in excessive in-flight vibrations of the elevator tab, consequent loss of the elevator tab, and loss of controllability of the airplane. This AD prohibits installation of certain repairs of the elevator tab.

Interim Action

This is interim action. The FAA is working with the manufacturer to identify proper action to ensure that unsafe conditions do not exist on airplanes that were repaired before the effective date of this AD. If a corrective action for the existing repairs is necessary, the FAA may consider further rulemaking in this regard.

The manufacturer also has advised that it currently is developing a modification that will positively address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.

Determination of Rule's Effective Date

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

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 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 rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-188-AD.” The postcard will be date stamped and returned to the commenter.

Regulatory Impact

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from 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

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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:

2001-14-05 Boeing: Amendment 39-12315. Docket 2001-NM-188-AD.

Applicability: All Model 737-600, -700, -700C, and -800 series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent installation of repairs of the elevator tab that are outside allowable limits, which could result in excessive in-flight vibrations of the elevator tab, and consequent loss of controllability of the airplane, accomplish the following:

Elevator Tab Repairs

(a) As of the effective date of this AD, no person shall install on any airplane any elevator tab repairs that are NOT done in accordance with Boeing All Operator Message M-7200-01-00756, Revision 1, dated May 29, 2001.

Alternative Methods of Compliance

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 1:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Effective Date

(d) This amendment becomes effective on July 26, 2001.

Issued in Renton, Washington, on July 2, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.