03-30675. Airworthiness Directives; Boeing Model 757-200 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757-200 series airplanes. This proposal would require repetitive inspections of the intercostals that back up the door stops and hinges at door 2 left and door 2 right for cracks, and corrective action, if necessary. This proposal also would provide for an optional terminating action for the repetitive inspections. This action is necessary to prevent fatigue cracks from propagating in the intercostals, which could lead to the loss of a door in flight and subsequent rapid decompression. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 26, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. FAA-2003-16646, 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. FAA-2003-16646” 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:

Mark Freisthler, 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:

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 FAA-2003-16646.” 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. FAA-2003-16646, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of cracking in the intercostals that provide structural support for the door stops and hinges at door 2 left and door 2 right for Boeing Model 757-200 series airplanes. The cause of the cracks is fatigue caused by the cyclic pressurization of the cabin. If left undetected, the fatigue cracks will continue to propagate. This condition, if not corrected, could result in the loss of a door in flight and subsequent rapid decompression.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Special Attention Service Bulletin 757-53-0086, dated March 14, 2002. The service bulletin describes the following procedures:

• Performing an initial detailed inspection for cracks in the intercostals that back up the door stops and hinges at door 2 left and door 2 right;
• For cases of no crack findings, performing repetitive dye penetrant or eddy current inspections for cracks in the intercostals that back up the door stops and hinges at door 2 left and door 2 right;
• For cases of crack findings or for an optional terminating action, installing a preventative modification of the intercostal (i.e. cut off the integral clips at the bend relief on the forward end of the intercostals and install new, separate clips to attach the intercostals to the frame at station 660); and/or replacing the intercostal with a new improved intercostal. Accomplishment of the preventative modification or replacement would eliminate the need for the repetitive inspections.

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 require accomplishment of the actions specified in the service bulletin described previously.

The FAA is not proposing to mandate the preventative modification of each intercostal or the replacement of each intercostal for several reasons:

1. Accessing the intercostals for inspection at the intervals is easily accomplished.

2. The cracks at the intercostals are easily detected by means of a detailed inspection.

3. The cracking of the intercostals could result in compromised structural integrity of the door stops; however, the detailed inspections will preclude the potential occurrence of continued cracking.

Cost Impact

There are approximately 95 airplanes of the affected design in the worldwide fleet. The FAA estimates that 55 airplanes of U.S. registry would be affected by this proposed AD.

We estimate that it would take approximately 8 work hours per airplane to accomplish the proposed inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the inspection on U.S. operators is estimated to be $28,600, or $520 per airplane, per inspection cycle.

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 proposed 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.

The optional preventative modification terminating action, if done, would take approximately 50 work hours per airplane at an average labor rate of $65 per work hour. Based on these figures, we estimate the cost of this optional terminating action to be $3,250 per airplane.

Parts for the optional replacement terminating action would cost approximately $692 for each Top Kit—Door Stop 1 Intercostal (L/H or R/H) and $4,581 for each Top Kit—Intercostal Replacement (L/H or R/H).

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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket FAA-2003-16646.

Applicability: Model 757-200 series airplanes, line numbers 1 through 95 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue cracks from propagating in the intercostals, which could lead to the loss of a door in flight and subsequent rapid decompression, accomplish the following:

Service Bulletin References

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-53-0086, dated March 14, 2002.

Initial Inspection

(b) Prior to the accumulation of 12,000 total flight cycles, or within 3,000 flight cycles after the effective date of this AD, whichever occurs later: Perform a detailed inspection for cracks of the intercostals that back up the door stops and hinges at door 2 left and door 2 right, per Part I of the service bulletin.

No Crack Findings: Repetitive Inspections

(c) If no crack is found during the inspection required by paragraph (b) of this AD, before further flight, do a dye penetrant or eddy current inspection for cracks of the intercostals that back up the door stops and hinges at door 2 left and door 2 right, per Part I of the service bulletin. Repeat thereafter at intervals not to exceed 3,000 flight cycles, until the preventative modification specified in paragraph (g) of this AD or the replacement specified in paragraph (h) of this AD has been accomplished.

Crack Findings: Modification/Replacement

(d) If, during the inspections required by paragraph (b) and/or (c) of this AD, any intercostal for door stop 1, 4, 5, 6, upper hinge, or lower hinge has cracks, but not beyond the aft edge of the bend relief radius: Before further flight, do the preventative modification specified in paragraph (g) of this AD or the replacement specified in paragraph (h) of this AD.

(e) If, during the inspections required by paragraph (b) and/or (c) of this AD, any intercostal for door stop 2 or 3 has cracks: Before further flight, do the replacement specified in paragraph (h) of this AD.

(f) If, during the inspections required by paragraph (b) and/or (c) of this AD, any intercostal has cracks that extend beyond the aft edge of the bend relief radius: Before further flight, do the replacement specified in paragraph (h) of this AD.

Terminating Actions

(g) Do the preventative modification on the intercostal per Part II of the service bulletin. Accomplishment of the preventative modification on an intercostal per Part II of the service bulletin constitutes terminating action for the repetitive inspection requirements of this AD for the modified intercostal only.

(h) Replace the intercostal with a new improved intercostal per Part III of the service bulletin. Accomplishment of the replacement of an intercostal with a new improved intercostal per Part III of the service bulletin constitutes terminating action for the repetitive inspection requirements of this AD for the replaced intercostal only.

Alternative Methods of Compliance

(i) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on December 4, 2003.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.