04-10240. Airworthiness Directives; Boeing Model 757-200 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 certain Boeing Model 757-200 series airplanes. This action requires initial and repetitive inspections of the fuselage skin and bear strap at the forward, upper corner of the L1 entry door cutout for cracking, and repair if necessary. This action also provides an optional terminating action for the repetitive inspections. This action is necessary to detect and correct cracking of the fuselage skin and bear strap at the forward, upper corner of the L1 entry door cutout, which could result in reduced structural integrity of the L1 entry door and consequent rapid decompression of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Effective May 24, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of May 24, 2004.

Comments for inclusion in the Rules Docket must be received on or before July 6, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2004-NM-44-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. 2004-NM-44-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 this AD 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; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call [phone], or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

FOR FURTHER INFORMATION CONTACT:

Dennis Stremick, 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 reports of cracking in the fuselage skin and bear strap at the forward, upper corner of the L1 entry door cutout on Boeing Model 757-200 series airplanes. A 6.0-inch crack was found on an airplane having 27,071 total flight cycles. A 1.4-inch crack was also found on an airplane having 29,340 total flight cycles, and a 1.7-inch crack was found in the bear strap on an airplane having 26,686 total flight cycles. These cracks were found during visual inspections during maintenance and were attributed to fatigue caused by pressurization cycles.

This condition, if not corrected, could result in reduced structural integrity of the L1 entry door and consequent rapid decompression of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Special Attention Service Bulletin 757-53-0089, dated March 18, 2004. The service bulletin describes procedures for performing initial and repetitive high frequency eddy current (HFEC) and low frequency eddy current (LFEC) inspections for cracking of the fuselage skin around the adjacent fasteners, along the edge of the skin and bear strap, and the bear strap around the fasteners adjacent at the forward, upper corner of the L1 entry door cutout; as applicable. The service bulletin specifies to contact Boeing for repair instructions for any cracks found during the HFEC and LFEC inspections.

The service bulletin also describes procedures for accomplishing a preventative modification, which eliminates the need for the repetitive inspections. The modification includes performing a general visual inspection to ensure that the fastener edge margins adjacent to the forward, upper corner of the L1 entry door cutout are 0.5 inch or greater; and related investigative/corrective actions, if necessary. Related investigative actions include repeating the general visual inspection at specified intervals if the margins are less than 0.50 inch or removing the fasteners and performing an HFEC inspection on the holes in the fuselage skin and bear strap if the margins are equal to or greater than 0.50 inch. The corrective actions include coldworking the fastener holes and installing over-sized fasteners if no crack is found during the HFEC inspection or contacting Boeing for repair instructions if any crack is found during either the general visual or the HFEC inspection. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

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 registered in the United States, this AD requires accomplishment of the actions specified in the service bulletin described previously, except as discussed below. This AD also provides for optional terminating action for the repetitive inspections.

Differences Between This AD and the Service Bulletin

Although the service bulletin specifies that operators contact the manufacturer for disposition of certain repair conditions, this AD requires operators to repair those conditions 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.

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 2004-NM-44-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
• Incorporation by reference
• 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:

2004-09-32 Boeing: Amendment 39-13622. Docket 2004-NM-44-AD.

Applicability: Model 757-200 series airplanes, line numbers 1 through 90 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct cracking of the fuselage skin and bear strap at the forward, upper corner of the L1 entry door cutout, which could result in reduced structural integrity of the L1 entry door and consequent rapid decompression of the airplane; accomplish the following:

Initial Inspections

(a) Within 500 flight cycles after the effective date of this AD, or within 90 days after the effective date of this AD, whichever occurs later: Do the inspections of the forward, upper corner of the L1 entry door cutout specified in paragraphs (a)(1), (a)(2), and (a)(3) of this AD, per Part 1 of the Work Instructions of Boeing Special Attention Service Bulletin 757-53-0089, dated March 18, 2004.

(1) Do a high frequency eddy current (HFEC) inspection for cracking of the fuselage skin around the adjacent fasteners.

(2) Do an HFEC inspection for cracking along the edge of the skin and bear strap.

(3) Do a low frequency eddy current (LFEC) inspection of the bear strap.

No Crack Detected: Repetitive Inspections

(b) If no crack is detected during any inspection required by paragraph (a) of this AD: Repeat the inspections required by paragraph (a) of this AD at intervals not to exceed 1,400 flight cycles.

Any Crack Detected: Repair

(c) If any crack is detected during any inspection required by this AD, and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.

Optional Terminating Modification

(d) As an alternative to accomplishing the inspections required by paragraphs (a) and (b) of this AD, do the optional preventative modification of the forward, upper corner of the L1 entry door cutout, and do all applicable related investigative/corrective actions by accomplishing all the actions specified in Part 2 of the Work Instructions of Boeing Special Attention Service Bulletin 757-53-0089, dated March 18, 2004. Accomplishment of the modification constitutes terminating action for the repetitive inspection requirements of this AD.

Alternative Methods of Compliance

(e)(1) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.

(2) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings.

Incorporation by Reference

(f) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Special Attention Service Bulletin 757-53-0089, dated March 18, 2004. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call [phone], or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Effective Date

(g) This amendment becomes effective on May 24, 2004.

Issued in Renton, Washington, on April 28, 2004.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.