02-17549. 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 for fatigue cracking of certain areas of the forward and aft frames of the cargo doors and repair, if necessary. This action is necessary to find and fix such cracking, which could lead to rapid depressurization of the airplane and result in reduced structural integrity of the cargo doorway. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 26, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-192-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-192-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:

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:

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 2001-NM-192-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-192-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report indicating that, during fatigue testing of the fuselage of a Boeing Model 757 series airplane, extensive cracking in the web and inner and outer chords of the number 1 and 2 cargo door frames was found. Subsequent to that testing, several reports were received from operators indicating cracking of the door frames on the number 1 and 2 cargo door frames on other Model 757 series airplanes. Cracking of the frame web was found on four of those airplanes. All of the cracking occurred at, or slightly outboard of, door stop number 6. Inner chord cracking ranged from 0.12 to 3.0 inches, and web cracking ranged from 0.40 inch to completely severed. The airplanes had accumulated between 22,199 and 27,528 flight cycles, and between 32,956 and 55,707 flight hours. Fatigue cracking of the cargo door frames, if not found and fixed, could lead to rapid depressurization of the airplane and result in reduced structural integrity of the cargo doorway.

Related Rulemaking

This proposed AD is related to AD 86-17-05R1, amendment 5714 (52 FR 32534, August 28, 1987), which is applicable to certain Boeing Model 727 series airplanes. That AD requires repetitive inspections for cracking of cargo door frames and repair, if necessary. That AD also provides a modification as terminating action for the forward frame of the number 3 cargo door.

This NPRM proposes similar actions for certain Boeing Model 757-200 series airplanes because the number 3 cargo door is very similar to the number 3 cargo door on Model 727 series airplanes.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 757-53A0080, dated February 3, 2000, which describes procedures for repetitive detailed and high frequency eddy current inspections for cracking of the cargo door frames, and repair, if necessary. Group 1 and 2 airplanes described in the service bulletin have only number 1 and 2 cargo doors. Group 3 airplanes have an additional number 3 cargo door. The inspections include the frame webs, frame inner and outer chords, bear strap, and skin panels between the upper and lower sills of the cargo door. The service bulletin also describes procedures for detailed inspections for stringers 29R and 24R.

The service bulletin describes procedures for repair of cracking that is confined to the frame webs. The service bulletin specifies contacting Boeing for repair information if any cracking is found in one of the frame chords, the bear strap, or the skin panel adjacent to the cargo doorway, or if damaged areas are outside specified limits. 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 This Proposed AD and the Service Information

The compliance times specified in the tables in Section 1.E., Compliance, of the referenced service bulletin identify various inspection thresholds for doing the initial detailed and high frequency eddy current inspections, based on the number of flight cycles the airplane has accumulated (between 27,000 and 30,000). However, we have determined that the inspections required by this proposed AD must be done before the accumulation of 22,000 total flight cycles or within 500 flight cycles after the effective date of the AD, whichever is later. This determination is based on fleet data received from the manufacturer which show that fatigue cracking of the frames on the cargo door occurred on affected airplanes that have accumulated between 22,199 and 27,528 total flight cycles.

Although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposed AD would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA, or in accordance with 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.

Interim Action

This is considered to be interim action. The manufacturer has advised that it currently is developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA may consider further rulemaking.

Cost Impact

There are approximately 57 airplanes of the affected design in the worldwide fleet. The FAA estimates that 28 airplanes of U.S. registry would be affected by this proposed AD.

For all airplanes it would take approximately 3 work hours per airplane to do the proposed high frequency eddy current and detailed inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspections proposed by this AD on U.S. operators is estimated to be $5,040, or $180 per airplane, per inspection cycle.

For Group 3 airplanes it would take approximately 1 work hour per airplane to do the proposed additional detailed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this proposed inspection on U.S. operators is estimated to be $60 per airplane, per inspection cycle.

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 2001-NM-192-AD.

Applicability: Model 757-200 series airplanes, line numbers 1 through 57 inclusive, 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 fatigue cracking of the cargo door frames, which could lead to rapid depressurization of the airplane and result in reduced structural integrity of the cargo doorway, accomplish the following:

Repetitive Inspections

(a) Before the accumulation of 22,000 total flight cycles or within 500 flight cycles after the effective date of this AD, whichever is later: Do the applicable inspections specified in paragraph (a)(1) and (a)(2) of this AD, per Boeing Alert Service Bulletin 757-53A0080, dated February 3, 2000.

(1) For all airplanes: Do detailed and high frequency eddy current (HFEC) inspections for cracking of the door frames of the number 1 and 2 cargo doors (includes the frame webs, frame inner and outer chords, bear strap, and skin panels between the upper and lower sills of the cargo door). Repeat the detailed inspections every 3,000 flight cycles, and the HFEC inspections every 12,000 flight cycles.

(2) For Group 3 airplanes: Do a detailed inspection for cracking of the door frame of the number 3 cargo door. Repeat the inspection every 3,000 flight cycles.

Note 2:

For the purposes of this AD, a detailed 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.”

Repair

(b) Before further flight, repair any cracking found in the frame webs per Boeing Alert Service Bulletin 757-53A0080, dated February 3, 2000. If any cracking is found in any other area and the service bulletin specifies to contact Boeing for disposition of those repairs, 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.

Note 3:

There is no terminating action currently available for the repetitive inspections required by 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, 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 4:

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

Special Flight Permit

(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 July 8, 2002.

Vi Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.