01-25617. Airworthiness Directives; Boeing Model 757 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757 series airplanes, that requires revising the Airworthiness Limitations Section of the maintenance manual (757 Airworthiness Limitations Instructions (ALI)). The revision will incorporate into the ALI certain inspections and compliance times to detect fatigue cracking of principal structural elements (PSE). This amendment is prompted by analysis of data that identified specific initial inspection thresholds and repetitive inspection intervals for certain PSEs to be added to the ALI. The actions specified by the proposed AD are intended to ensure that fatigue cracking of various PSEs is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.

DATES:

Effective November 20, 2001.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of November 20, 2001.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Dennis Stremick, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 757 series airplanes was published in the Federal Register on January 29, 1999 (64 FR 4367). That action proposed to require revising Section 9 of the Airworthiness Limitations Section of the maintenance manual (757 Airworthiness Limitations Instructions (ALI)). The revision would incorporate certain inspections and compliance times to detect fatigue cracking of principal structural elements (PSE).

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Support for the Notice of Proposed Rulemaking (NPRM)

One commenter supports the NPRM.

1. Request for Specific Task Content and Implementation Intervals

The manufacturer requests that a newer revision, dated November 1998 of Boeing 757 Maintenance Planning Data, Boeing Document D622N001-9, be specified in the final rule. The manufacturer notes that the November 1998 revision contains qualifying statements that, for some affected airplanes, would reduce the scope of some of the actions required by the May 1997 revision, which was cited in the NPRM as the appropriate source of service information. Another commenter states that it opposes the NPRM, but if the FAA issues the final rule, the operator requests that the identical task content and interval of implementation specified in Revision November 1998 of Boeing Document D622N001-9 be followed in the final rule.

The FAA concurs that the final rule should specify more recent service information than the May 1997 revision. Since the issuance of the NPRM, Boeing Document D622N001-9 (Section 9), dated November 1998, has been issued by the manufacturer and approved by the FAA. We have, therefore, included the November 1998 revision as an option to accomplish in lieu of the May 1997 revision specified in paragraph (a) of this final rule. We consider the requirements of this final rule to be interim action until such time that a new NPRM may be developed to require accomplishment of the November 1998 revision of Boeing Document D622N001-9.

2. Request To Extend Reporting Requirement Period

One commenter requests that the reporting period (as specified in Section 9) be extended from the proposed 10 days to 20 days. The commenter notes that 20 days would allow enough time to collate all inspection findings and transmit a single data package for each airplane.

The FAA agrees with the commenter. However, since Section 9 is not specifically identified in the NPRM (it is embodied in the reference to Subsection B of Boeing Document D622N001-9), we have incorporated the reference to the reporting requirement that was specified in Note 2 of the NPRM into a new paragraph (b) of the final rule. Paragraph (b) of the final rule clarifies that the reporting requirement embodied in the reference to Subsection B has been extended to within 20 days after performance of inspections required by paragraph (a) of the final rule.

3. Request To Provide Further Clarification Regarding Flight Cycles vs. Flight Hour Thresholds

One commenter, the airplane manufacturer, states that, since there is reference to the 25,000-flight-cycle threshold and 50,000-flight-cycle threshold in the preamble of the NPRM, it should also be noted that there is a flight cycle versus flight hour threshold for some items that are sensitive to flight length. Also, the commenter notes that there are some other restrictions, such as a calendar threshold of 20 years unless an FAA-approved Corrosion Prevention and Control Program (CPCP) has been implemented, as well as a requirement to revert any escalated structural inspections back to the intervals specified in Section 8 of the Maintenance Planning Data (MPD) document.

The FAA acknowledges that there is other information available in the revision to the MPD, which was not discussed in the preamble of the NPRM. The information that we provided in the preamble of the NPRM was intended to be representative of the information that was used to determine that none of the airplanes affected is likely to reach the threshold for certain PSEs, which are identified as Structurally Significant Items (SSIs) in the ALIs. Since the Discussion section in the preamble of the NPRM does not reappear in the final rule, no change to the final rule is necessary in this regard.

4. Request To Revise Certain Preamble Information

One commenter, the manufacturer, notes that some necessary clarifications and corrections to information included under the heading “Actions Taken by the Manufacturer” in the preamble of the NPRM. The commenter advises that reference to the word “recently” is misleading since most of the listed actions occurred many years ago. The commenter also recommends listing the actions in order of significance and adding additional items to the actions specified under that heading.

The FAA acknowledges that certain information under that heading could be revised for clarification purposes. However, since the information in the paragraph under that heading in the preamble of the NPRM does not reappear in the final rule, no change to the final rule is necessary in this regard.

5. Request To Revise Certain SSI Repair Actions

One commenter requests that the proposed requirements of the NPRM be revised to reflect certain repair actions for SSIs that were installed before the effective date of the AD and certain other repair actions for SSIs that are installed after the effective date of the AD.

The FAA does not agree. In the case of this final rule, the required action is simply to revise Section 9 of the Model 757 MPD by incorporating Subsection B of Boeing Document D622N001-9, Revision May 1997 or November 1998. The specific information contained in the MPD is developed (with the concurrence of the FAA) and then printed by the manufacturer. We point out that the requirements of this AD do not address the accomplishment of the specific information contained in Subsection B. The effect of requiring that the MPD be revised to incorporate the current version of the ALI is that, in accordance with 14 CFR Part 91.403(c), operators are then required to comply with limitations contained in the MPD. This is analogous to the effect of requiring a revision to the operating limitations. (In accordance with 14 CFR Part 91.9(a), operators are required to comply with the revised operating limitations.) However, a new NOTE 1 has been added to the AD to address the possible need to obtain approval of alternative methods of compliance (AMOC) for certain repairs. Therefore, no further change to the final rule is necessary in this regard.

6. Request To Specify Proper MPD Subsection

One commenter, the manufacturer, notes that the reference in the NPRM to “Chapter B” of Section 9 of Boeing 757 MPD is incorrect. The commenter states that the correct title is “Subsection B.” The FAA agrees and has revised the final rule accordingly.

7. Request To Withdraw the NPRM

Several commenters state that the NPRM is unnecessary.

One commenter states that the NPRM is unnecessary because Section 9 of the MPD already mandates compliance with Airworthiness Certification Maintenance Requirements.

Another commenter states that the NPRM is unnecessary as long as Boeing agrees to incorporate the changes on their own within the proposed three-year compliance time. The commenter states that issuing an AD to require the manufacturer to comply with a certain revision of its own manuals will only require more regulation down the road. The commenter explains that, when it is time to revise the MPD, an Alternate Means of Compliance (AMOC) would be required prior to using the new revision.

Another commenter states that the rule is unnecessary because operators cannot revise a Boeing document.

The FAA infers that, since these commenters state that they believe the NPRM is unnecessary, the commenters would like the NPRM to be withdrawn. We do not agree. The airworthiness limitations, like the operating limitations, are a part of the type certificate for an airplane. Once an airworthiness certificate is issued for an airplane certifying that it conforms to an approved type design, this design is “locked” in the sense that the manufacturer cannot unilaterally change it for the subject airplane. Therefore, when the manufacturer makes any subsequent changes to the type certificate, including changes to the operating or airworthiness limitations, those changes are legally required only for products that are submitted for airworthiness certification based on a showing of conformity to the later design.

Thus, for many years, the FAA has imposed operating restrictions that are necessary to address identified unsafe conditions by requiring revisions to the operating limitations section of the Airplane Flight Manual (AFM). (Revision of the AFM by the type certificate holder would be effective only for airplanes produced after that revision.) Similarly, Boeing's revision to the ALI was effective only for airplanes later certificated with those revisions included in their type certificate. For this reason, as stated in the NPRM, we must engage in rulemaking (i.e., issuance of an AD), in order to make the revisions mandatory for previously certificated airplanes.

While the ALIs are contained in a “Boeing document” in the sense that Boeing originally produced it, the document, nevertheless, is a part of the instructions for continued airworthiness that operators must use to maintain the airplane properly. As explained in the NPRM, the effect of requiring that the document be revised to incorporate the current version of the ALI is that, in accordance with 14 CFR part 91.403(c), operators are then required to comply with those limitations. This is analogous to the effect of requiring a revision to the operating limitations: in accordance with 14 CFR part 91.9(a), operators are required to comply with the revised operating limitations.

Of course, those operators that have previously revised the ALI (or incorporated the revision into their maintenance programs) are given credit for having previously accomplished the requirements of this AD, as allowed by the phrase, “unless accomplished previously.” The legal effect is the same: the operator is required to comply with the limitations per 14 CFR part 91.403(c).

8. Request To Clarify Intent of the NPRM

One commenter states that paragraph (b) of the NPRM (paragraph (c) of the final rule) appears to conflict with the original intent of the NPRM. Paragraph (b) of the NPRM specifies that, after revising the MPD in accordance with paragraph (a) of the NPRM, no alternative inspections or inspection intervals shall be approved for the PSEs. The commenter explains that it is not clear why paragraph (b) is needed if the inspections were accomplished in accordance with 14 CFR parts 43 and 91. The commenter states that paragraph (b) of the NPRM essentially defeats the stated purpose of the NPRM, which is to have operators record their AD compliance only once (at the time the operator's maintenance program is changed), in order to reduce the burden of record keeping and tracking.

The FAA does not agree. The purpose of this AD is to address the identified unsafe condition of fatigue cracking in certain PSEs. We have determined that, in order to accomplish that purpose, those airplanes must be brought into compliance with the certification basis, i.e., 14 CFR Part 25.571, amendment 25-45. Revising the ALI, as required by paragraph (a) of this AD, fulfills this purpose. Once an operator records that the ALI have been revised, additional record keeping of AD compliance is not required, since the actual accomplishment of the inspections specified in the ALI is required, not by the AD, but by 14 CFR 91.403(c). We point out that paragraph (c) of the final rule merely repeats and enforces the provision presently existing in the Boeing 757 MPD, which requires any revision of the airworthiness limitations to be approved by the Manager, Seattle Aircraft Certification Office, FAA. We consider that paragraph (c) of the final rule, therefore, does not conflict with the intention to have operators record their AD compliance only once. No change is necessary to the final rule in this regard.

9. Request To Permit Compliance With Damage Tolerance Rating (DTR) System

One commenter requests that paragraph (b) of the NPRM be revised to permit compliance with the DTR system. The commenter states that the supplemental inspection program uses the DTR system to determine the inspections/inspection intervals necessary to provide adequate fatigue damage detection for each SSI. The commenter notes that the DTR check forms define inspection options permitting an operator to customize an inspection program.

The FAA does not agree that a revision is necessary. The DTR system is specifically referenced in the ALI, and its use is allowed by paragraph (a) of this AD. Therefore, there is no need to obtain a separate approval for its use. This AD does not specifically address (or restrict) the use of the DTR specified in the ALI. No change is necessary to the final rule in this regard.

10. Requests To Require Incorporation of ALI Into Operations Specifications

One commenter, the manufacturer, suggests that the NPRM be revised to require the operators to incorporate the ALIs into the appropriate Maintenance Program Specification (Operations Specification).

The FAA does not agree that incorporation of the ALIs into the Operations Specifications (Ops Specs) is appropriate. Operation of certain transport airplanes may be exclusively under the provisions and requirements of part 91, and therefore, operators would not even be required to maintain Ops Specs. Further, Ops Specs simply authorize the use of a Continuous Airworthiness Maintenance Program (CAMP) for the operator's individual airplane models and specify, in particular, that procedures, standards, checks, service, repair, and/or preventive maintenance, and tests, shall be described in the certificate holder's manual.

The commenter further requests that the requirements of the NPRM be written such that the operator's Ops Specs is continuously updated with the current revision of Section 9 of the MPD. If that process is not possible, the commenter suggests that the requirements be accomplished in accordance with the latest FAA-approved revision of Section 9 of the MPD.

The FAA does not agree with the commenter's requests. We note that the commenter provided no justification or benefit of implementing the suggested changes. In response to the suggestion that the Ops Specs be continuously updated with current revisions of Section 9 of the MPD, we note that incorporation of new revisions of the ALI into the Ops Specs would have the effect of imposing new requirements without providing notice to the public and opportunity for comment.

However, in this case, the request to reference a specific later revision is acceptable as an alternative method of compliance, as explained previously in comment number 1. of this final rule. Therefore, we have revised paragraph (a) of the final rule to add the “November 1998” revision of Section 9 of the MPD as an optional or alternative method of compliance with the requirements of this AD.

11. Request To Omit Apostrophe in Acronyms

The manufacturer requests that the apostrophe be deleted on plural use of acronyms, e.g., PSEs and ADs. The FAA acknowledges that there are different applications of the use of apostrophes for plural acronyms. For the purpose of consistency in this AD, we have revised all plural acronyms to omit the apostrophe.

Editorial Changes Appearing in the Final Rule

We have revised the contents of Note 1 of the final rule to clarify for operators the intent and purposes of that note when performing inspections in accordance with certain airworthiness limitations documents.

We also note that, while SSIs are a subset of PSEs, the Federal Aviation Regulations (FAR) related to damage tolerance refer only to PSEs. Therefore, for the purposes of this AD, we consider the two terms interchangeable. A new NOTE 2 has been added to the final rule to clarify this information.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 764 Boeing Model 757 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 300 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $18,000, or $60 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this 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.

Although this AD requires only a revision to the current ALI, the FAA recognizes that the inspections contained in the ALI will then be required by parts 43 and 91 of the FAR. The FAA estimates that it will take approximately 1,000 work hours to accomplish all of the ALI inspections. At an average labor rate of $60 per work hour, the cost to perform the ALI inspections (required by FAR parts 43 and 91, rather than by part 39) will be approximately $60,000 per airplane. The FAA notes that the majority of work hours needed to perform the inspections will be expended when an affected airplane reaches the 50,000-flight-cycle threshold. Based upon current airplane utilization, the FAA estimates that no airplane will reach this threshold for at least 10 years.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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:

2001-20-12 Boeing: Amendment 39-12460. Docket 98-NM-225-AD.

Applicability: Model 757 series airplanes having line numbers 1 through 764 inclusive, certificated in any category.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these inspections is required by 14 CFR Part 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these inspections, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR part 91.403(c), the operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include a description of the changes to the required inspections that will ensure the continued damage tolerance of the affected structure. The FAA has provided guidance for this determination in Advisory Circular (AC) 25-1529.

Compliance: Required as indicated, unless accomplished previously.

To ensure continued structural integrity of these airplanes, accomplish the following:

Revision of Airworthiness Limitations and Certification Maintenance Requirements

(a) Within 3 years after the effective date of this AD, revise Section 9 of the Boeing 757 Maintenance Planning Data (MPD) Document entitled “Airworthiness Limitations and Certification Maintenance Requirements (CMRs)” to incorporate Subsection B. of Boeing Document D622N001-9, Revision “May 1997,” or Revision “November 1998.”

Note 2:

For the purposes of this AD, the terms Principal Structural Elements (PSEs) as used in this AD, and Structural Significant Items (SSIs) as used in Section 9 of Boeing 757 MPD Document, are considered to be interchangeable.

Reporting Requirements

(b) Although Subsection B. of Boeing Document D622N001-9, dated November 1998, references a requirement that cracks found during the specified inspections be reported with 10 days, this AD requires that those reports be submitted to the Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, within 20 days after the inspection. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501, et seq.) and have been assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance

(c) Except as provided in paragraph (d) of this AD: After the actions required by paragraph (a) of this AD have been accomplished, no alternative inspections or inspection intervals shall be approved for the PSEs contained in Boeing Document D622N001-9, Revision “May 1997” or “November 1998.”

(d) 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

(e) 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.

Incorporation by Reference

(f) The MPD revision shall be done in accordance with Boeing 757 Maintenance Planning Data Document, Section 9, Boeing Document D622N001-9, Revision “MAY 1997;” or Boeing 757 Maintenance Planning Data Document, Section 9, Boeing Document D622N001-9, Revision “November 1998.” Boeing 757 Maintenance Planning Data Document, Section 9, Boeing Document D622N001-9, Revision “MAY 1997” contains the following effective pages:

Page No.	Revision shown on page
List of Effective Pages—Page 9.0-4	May 1997.

Boeing 757 Maintenance Planning Data Document, Section 9, Boeing Document D622N001-9, Revision “November 1998” contains the following effective pages:

Page No.	Revision shown on page
List of Effective Pages—Page 9.0-5	November 1998.

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 Airplane Group, 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 Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(g) This amendment becomes effective on November 20, 2001.

Issued in Renton, Washington, on October 4, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.