04-7295. Airworthiness Directives; Boeing Model 757-200, -200PF, and -200CB 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, -200PF, and -200CB series airplanes. This proposal would require an inspection of certain ballscrews of the trailing edge flap system to find their part numbers, and replacement of the ballscrews with new, serviceable, or modified ballscrews if necessary. This action is necessary to prevent a flap skew due to insufficient secondary load path of the ballscrew of the trailing edge flaps in the event that the primary load path fails, which could result in possible loss of a flap and reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by May 17, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-166-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. 2003-NM-166-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:

Douglas Tsuji, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, 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 2003-NM-166-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. 2003-NM-166-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report from Boeing that certain ballscrews at positions 1 and 8 of the trailing edge flaps do not have a sufficient secondary load path on certain Boeing Model 757-200, -200PF, and -200CB series airplanes. Without a sufficient secondary load path, the ballnut can slip along the ballscrew if the primary load path fails. This condition, if not corrected, could result in a flap skew in the event of failure of the primary load path, which could result in possible loss of a flap and reduced controllability of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 757-27A0139, dated June 16, 2003, which describes procedures for an inspection of certain ballscrews of the trailing edge flap system to find their part numbers, and replacement of the ballscrews with new, serviceable, or modified ballscrews if necessary. 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.

Cost Impact

There are approximately 979 airplanes of the affected design in the worldwide fleet. The FAA estimates that 644 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed inspection at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $41,860, or $65 per airplane.

Replacement of a ballscrew with a new or serviceable ballscrew, if required, would take about 3 work hours per ballscrew, at an average labor rate of $65 per work hour. Required parts would cost about $8,400 per ballscrew. Based on these figures, we estimate the cost of a repair to be $8,595 per ballscrew (there are two ballscrews per airplane).

Removal, modification, and reinstallation of a ballscrew, if required, would take about 6 work hours per ballscrew, at an average labor rate of $65 per work hour. Required parts would cost about $553 per ballscrew. Based on these figures, we estimate the cost of a repair to be $943 per ballscrew (there are two ballscrews per airplane).

The cost impact figures discussed above are 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.

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 2003-NM-166-AD.

Applicability: Model 757-200, -200PF, and -200CB series airplanes, line numbers 1 through 979 inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent a flap skew due to insufficient secondary load path of the ballscrew of the trailing edge flaps in the event that the primary load path fails, which could result in possible loss of a flap and reduced controllability of the airplane, accomplish the following:

Inspection and Corrective Action

(a) Within 36 months after the effective date of this AD, do an inspection of the ballscrews of the trailing edge flap system to find their part numbers (P/N) per the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0139, dated June 16, 2003. If the P/N of the ballscrew is S251N401-5 (Thomson Saginaw P/N 7820921) or S251N401-9 (Thomson Saginaw P/N 7821341), within 36 months after the effective date of this AD, replace the ballscrew with a new, serviceable, or modified ballscrew per the service bulletin.

Parts Installation

(b) As of the effective date of this AD, no person may install a trailing edge flap ballscrew, P/N S251N401-5 or -9, on any airplane.

Alternative Methods of Compliance

(c) 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 March 24, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.