01-29598. Airworthiness Directives; Boeing Model 727 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 all Boeing Model 727 series airplanes. This proposal would require repetitive inspections for cracking of the upper chord of the rear spar of the wing, and corrective action, if necessary. This action is necessary to find and fix such cracking, which could result in fuel leaking through the cracks, reduced structural integrity of the wing, and separation of the wing from the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 14, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-203-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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-203-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 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:

Walter Sippel, 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-203-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. 2001-NM-203-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports that fatigue cracking has been found in the upper chord of the rear spar of the wing at approximately wing station (WS) 293 on several Boeing Model 727 series airplanes. In most cases, the cracking was discovered during inspections to determine the source of fuel leaks on the left wing of the airplane. All of the cracks were fully through the vertical flange of the chord, and several extended into the horizontal flange to the first row of fasteners that attach the skin of the wing to the chord. During routine visual inspections, this cracking would not be seen until it extends from under the flanges of the stiffener installed at WS 293. Cracking of the upper chord of the rear spar, if not corrected, could result in fuel leaking through the cracks, reduced structural integrity of the wing, and separation of the wing from the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 727-57-0184, dated August 16, 2001, which describes procedures for repetitive detailed visual and high frequency eddy current inspections for cracking of the upper chord of the rear spar at approximately WS 293. The detailed visual inspection also includes an inspection of the surface finish for damage or deterioration (discoloration, blistering, raised or rough areas), removal of the finish, if necessary, and blending of the area until smooth, if necessary. If any cracking is found, the service bulletin specifies to contact Boeing for repair instructions. 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, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished according to a method approved by the FAA, or according to data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) who has been authorized by the FAA to make such findings.

Operators also should note that, if any damage or deterioration, but no cracking, is found during the proposed inspection, the proposed AD would require removal of the finish, blending of the area until smooth, and reapplication of the finish. However, if the necessary blend-out is outside the limits specified in the Boeing 727 SRM, the proposed AD would require repair according to a method approved by the FAA or according to data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the FAA to make such findings.

Operators also should note that, although the effectivity summary in paragraph 1.A.1. of the referenced service bulletin identifies only Model 727-100 and -200 series airplanes as being subject to the actions specified in the service bulletin, we have determined that the proposed actions apply to all Model 727 series airplanes, including Model 727, 727-100C, 727-200F, and 727C series airplanes.

Cost Impact

There are approximately 1,375 airplanes of the affected design in the worldwide fleet. The FAA estimates that 912 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 12 work hours per airplane to accomplish the proposed inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $656,640, or $720 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.

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 2001-NM-203-AD.

Applicability: All Model 727 series airplanes, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To find and fix cracking of the upper chord of the rear spar of the wing, which could result in fuel leaking through the cracks, reduced structural integrity of the wing, and separation of the wing from the airplane, accomplish the following:

Repetitive Inspections

(a) Prior to the accumulation of 20,000 total flight cycles, or within 500 flight cycles after the effective date of this AD, whichever is later, do detailed visual and high frequency eddy current inspections for cracking of the upper chord of the rear spar of the wing, according to Boeing Service Bulletin 727-57-0184, dated August 16, 2001. The detailed visual inspection must include an inspection of the surface finish for damage or deterioration (discoloration, blistering, raised or rough areas), as described in the service bulletin. Repeat all inspections every 4,500 flight cycles.

Note 2:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Repairs

(b) If any cracking, damage, or deterioration is found during any inspection required by paragraph (a) of this AD: Before further flight, do paragraph (b)(1) or (b)(2) of this AD, as applicable.

(1) If any damage or deterioration but no cracking is found, remove the finish, blend the area smooth, and reapply the finish according to Boeing Service Bulletin 727-57-0184, dated August 16, 2001.

(i) If the blend-out is within the limits specified in Section 57-10-1 of the Boeing 727 Structural Repair Manual (SRM), no further action is required by this paragraph.

(ii) If the blend-out is outside the limits specified in Section 57-10-1 of the Boeing 727 SRM, before further flight, repair according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to 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 by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

(2) If any cracking is found, repair according to a method approved by the Manager, Seattle ACO, or according to data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

Alternative Methods of Compliance

(c) 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 ACO. 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 3:

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

(d) 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.

Issued in Renton, Washington, on November 21, 2001.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.