Airworthiness Directives; Boeing Model 727 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 727 series airplanes, that requires repetitive structural inspections of certain aging airplanes, and repair, if necessary. This amendment also provides for optional terminating action for the repetitive inspections. This amendment is prompted by reports of incidents involving fatigue cracking and corrosion in transport category airplanes that are approaching or have exceeded their economic design service goal. The actions specified by this AD are intended to prevent degradation of the structural capabilities of the affected airplanes. This AD relates to the recommendations of the Airworthiness Assurance Task Force assigned to review Model 727 series airplanes, which indicate that, to assure long term continued operational safety, various structural inspections should be accomplished.

DATES:

Effective May 16, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of May 16, 2000.

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 FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. 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:

Walter Sippel, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.

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 727 series airplanes was published in the Federal Register on June 25, 1999 (64 FR 34168). That action proposed to require repetitive structural inspections of certain aging airplanes, and repair, if necessary.

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 Proposal

The Air Transport Association (ATA) of America, on behalf of three of its members, indicates that these members generally support the proposal. One of those members states that it does not operate any Boeing Model 727-200 series airplanes, line numbers 1 through 1214; another member has no objections to the proposed rule; and another member has no objection to the intent of the proposed rule but proposes certain clarifications.

Requests To Correct References

Two commenters state that a number of incorrect references are cited in the proposed AD. The commenters recommend changing references from “AD 94-05-04” to “AD 90-06-09” in the “Other Relevant Rulemaking” and “Differences Between Proposed Rule and Service Bulletin” sections of the proposed AD, the applicability of the proposed AD, and paragraph (d) of the proposed AD [cited as paragraphs (g)(1) and (g)(2) in the final rule]. One of the commenters contends that Revision 3 of Boeing Service Bulletin 727-57-0127, dated August 24, 1989 (which is referenced in Boeing Document Number D6-54860), clearly references repetitive inspections at intervals of 14,000 flight cycles. However, the Boeing document only specifies an inspection in accordance with Note 2 of Revision 3 of the service bulletin, and Note 2 does not refer to the repetitive inspections. Another of the commenters contends that Revision 2 of the service bulletin, dated February 13, 1976, was cited in the Boeing document and was mandated by AD 94-07-08.

Although the “Other Relevant Rulemaking” and “Differences” sections are not included in the final rule, the FAA concurs that it is necessary to change all references from “AD 94-05-04” to “AD 90-06-09” because the proposed AD incorrectly referenced AD 94-05-04. However, with regard to the correct revision number of the service bulletin, the FAA points out that AD 94-07-08 specifies Revision 3 rather than Revision 2 of the service bulletin, and that Revision 2 of the service bulletin is relevant to AD 90-06-09. To clarify the applicability of the final rule, the FAA has changed the AD reference, and clarified that the actions are to be accomplished for certain airplanes on which the modification specified by either Revision 2 or Revision 3 of the service bulletin has not been accomplished. In addition, the AD references are changed in paragraphs (g)(1) and (g)(2) of the final rule.

Request To Extend Compliance Time for Initial Inspection

The commenter states that the compliance time in paragraph (a) of the proposed AD should be extended. That compliance time assumes that all Model 727 series airplanes have exceeded the initial inspection threshold, as it requires the initial inspection within 2,000 flight cycles [a phase-in (grace) period] after the effective date of the AD. The commenter points out that Note 2 in Part III of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0127, Revision 3, specifies a threshold of 16,000 flight cycles and a phase-in period if an airplane has exceeded that threshold. The commenter has reviewed the active fleet of Model 727 series airplanes and has found that, at the present time, there are 36 airplanes that have accumulated less than 14,000 total flight cycles. The commenter also states that if the initial inspection has been accomplished in accordance with AD 94-07-08, that AD also requires repetitive inspection intervals of 14,000 total flight cycles. Therefore, the commenter recommends extending the compliance time in paragraph (a) of the proposed AD.

The FAA concurs that the compliance time should be extended, and that whether the initial inspection has or has not been accomplished in accordance with AD 94-07-08 should be considered. Therefore, paragraph (a) of the final rule has been revised to specify the inspection requirements for those airplanes on which the initial inspection has not been accomplished in accordance with AD 94-07-08, and a new paragraph (b) has been added to specify the inspection requirements for those airplanes on which the initial inspection has been accomplished in accordance with AD 94-07-08. [Paragraphs (a)(1) and (a)(2) of the proposed AD have been renumbered as paragraphs (c) and (d) in the final rule.]

Request To Clarify Type of Inspection

One commenter states that although the proposed AD requires a “dye penetrant inspection,” Revision 3 of the Boeing service bulletin only specifies a “penetrant inspection,” and does not reference a Boeing process specification, Non-Destructive Test manual reference, or any other kind of reference as to the type of penetrant inspection (e.g., dye or fluorescent) that should be performed.

The FAA acknowledges that clarification of the type of inspection is necessary. Paragraph (a)(1) of the proposed rule specifies a “dye penetrant inspection” in accordance with Boeing Service Bulletin 727-57-0127, Revision 3, and Boeing Standard Overhaul Practices Manual D6-51702, Chapter 20-20-02, Revision 79, dated March 1, 1999. Although the service bulletin specifies a “penetrant inspection,” Figure 1 of the Standard Overhaul Practices Manual specifies a “fluorescent dye penetrant inspection (Type I).” Based on the type of inspection included in the manual, the FAA has clarified the type of inspection specified in the preamble and paragraph (c) of the final rule.

Request To Clarify Terminating Action Required by AD 94-07-08

One commenter states that operators have expressed concerns that another AD is being written to mandate the inspections required by Boeing Service Bulletin 727-57-0127 [Revision 3], when AD 94-07-08 currently mandates such inspections. However, the proposed AD does not state that it will supersede the inspection requirements of Service Bulletin 727-57-0127, as mandated by AD 94-07-08. Therefore, the commenter recommends adding a note to the proposed AD stating that “Upon incorporation of the requirements of this AD, the inspection requirements of Boeing Service Bulletin 727-57-0127 mandated by AD 94-07-08 may be deleted.”

The FAA acknowledges the concern expressed by the commenter that the proposed AD requires inspections currently required by paragraph (a) of AD 94-07-08. In response, the FAA has clarified in paragraph (g)(1) of the final rule that accomplishment of the inspections required by this AD constitutes terminating action for the inspections required by paragraph (a) of AD 94-07-08, as specified in Boeing Service Bulletin 727-57-0127, Revision 3.

Request To Delete Reference to Corrosion

One commenter states that, although the summary of the proposed AD states that the AD was prompted by reports of incidents involving fatigue cracking and corrosion found on older airplane models, Boeing Service Bulletin 727-57-0127 only addresses fatigue cracking and does not address corrosion. The FAA infers that the commenter suggests deleting the reference to corrosion in the summary of the proposed rule.

The FAA does not concur. Although the service bulletin does not include a reference to corrosion and only includes a reference to fatigue cracking, the FAA points out that the Working Group's reference to Boeing Document Number D6-54860, “Aging Airplane Service Bulletin Structural Modification Program—Model 727,” Revision C, dated December 11, 1989 (as cited in the Discussion paragraph of the proposed AD), was established to address problems associated with both fatigue cracking and corrosion. In light of this, the FAA considers that the reference to corrosion is appropriate, and no change to the final rule is necessary in this regard.

Request To Clarify Inspection Requirement for Airplanes in Groups 4 and 5

One commenter recommends revising “Other Relevant Rulemaking” in the proposed AD to clarify that AD 94-07-08 inadvertently omitted the requirement to mandate repetitive inspections for certain wing ribs on airplanes in groups 4 and 5, because Section 4 of Boeing Document Number D6-54860 references Revision 2 of Boeing Service Bulletin 727-57-0127. The commenter adds that Revision 3 of the service bulletin specifies an additional rib inspection for airplanes in groups 4 and 5 only, and no additional requirements for airplanes in groups 1, 2, 3, and 6.

Although “Other Relevant Rulemaking” is not included in the final rule, the FAA acknowledges that AD 94-07-08 inadvertently omitted a requirement for the repetitive inspections. However, the FAA points out that the commenter was mistaken in stating that Boeing Document Number D6-54860, references Revision 3 (rather than Revision 2) of the service bulletin. In addition, Revision 3 of the service bulletin does include the additional rib inspection for airplanes in groups 4 and 5. Therefore, no change to the final rule is necessary in this regard.

Request To Allow Later Revisions of Service Bulletins

One commenter states that, in the “Initial Inspection” section of the NPRM, the reference documents for accomplishing the dye penetrant and high frequency eddy current inspections include a specific revision number for the service bulletin. The commenter suggests adding “or later revisions” so that when future revisions are released, there will not be any confusion as to which revision to use.

The FAA does not concur with the request to revise the AD to reference later revisions of the service bulletin, because it cannot approve the use of a document that does not yet exist. In addition, when a service bulletin is referenced in an AD, the use of the phrase, “or later FAA-approved revisions,” violates Office of the Federal Register regulations regarding approval of materials that are incorporated by reference. Therefore, the FAA has determined that it is necessary to specify a certain revision number for all service bulletins specified in the final rule. However, the FAA points out that operators may submit any requests to use a later service bulletin through an appropriate FAA Principal Maintenance Inspector, as provided for by paragraph (h) of this AD.

Request To Revise Inspection Intervals

One commenter recommends extending the inspection intervals in paragraph (b) of the proposed AD to give credit for the accomplishment of initial or previous inspections in accordance with AD 94-07-08, and basing the next required inspection interval on the date the previous inspection was accomplished.

The FAA does not concur that it is necessary to revise the inspection intervals required by paragraph (b) of the proposed AD [cited as paragraph (e) of the final rule] because paragraph (a) of the proposed AD [cited as paragraph (b) of the final rule] states that the initial inspection is required within 2,000 flight cycles after the effective date of this AD, “unless accomplished within the last 12,000 flight cycles in accordance with AD 94-07-08.” Therefore, the proposed AD provides credit for a previous inspection that was accomplished within 12,000 flight cycles; as a result, the proposed AD allows operators to repeat the inspection within 14,000 flight cycles after the last inspection. No change to the final rule is necessary in this regard.

Explanation of Change Made to the Proposal

The FAA has revised paragraph (c) of the proposed rule that requires repair in accordance with Boeing Service Bulletin 727-57-0127, Revision 3. That paragraph, renumbered as paragraph (f) in the final rule, adds that repair also may 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.

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 975 Model 727 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 538 airplanes of U.S. registry will be affected by this AD, that it will take approximately 300 work hours per airplane to accomplish the required inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspections required by this AD on U.S. operators is estimated to be $9,684,000, or $18,000 per airplane, per inspection cycle.

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.

Should an operator elect to accomplish the optional terminating action rather than continue the repetitive inspections, it would take approximately 900 work hours per airplane to accomplish the modification, at an average labor rate of $60 per work hour. Required parts will cost approximately $31,144 per airplane. Based on these figures, the cost impact of this optional terminating action is estimated to be $85,144 per airplane.

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 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.

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

2000-07-12 Boeing: Amendment 39-11666. Docket 99-NM-53-AD.

Applicability: Model 727-100, -100C, and -200 series airplanes, line numbers 1 through 1214 inclusive; certificated in any category; except those on which the modification specified by either Boeing Service Bulletin 727-57-0127, Revision 2, dated February 13, 1976, or Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989, has been installed.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (h) 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 prevent degradation of the structural capabilities of the affected airplanes, accomplish the following:

Initial Inspection

(a) For those airplanes on which the initial inspection has not been accomplished in accordance with AD 94-07-08, amendment 39-8866: Prior to the accumulation of 16,000 total flight cycles or within 2,000 flight cycles after the effective date of this AD, whichever occurs later, accomplish the inspections required by either paragraph (c) or (d) of this AD.

(b) For those airplanes on which the initial inspection has been accomplished in accordance with AD 94-07-08, amendment 39-8866: Within 2,000 flight cycles after the effective date of this AD, unless accomplished within the last 12,000 flight cycles in accordance with AD 94-07-08, accomplish the inspections required by either paragraph (c) or (d) of this AD.

(c) Perform a fluorescent dye penetrant inspection (Type I) to detect cracking of certain wing ribs at the rib-to-stringer attachment in the areas specified in Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989; in accordance with Boeing Standard Overhaul Practices Manual D6-51702, Chapter 20-20-02, Revision 79, dated March 1, 1999.

(d) Perform a high frequency eddy current inspection to detect cracking of certain wing ribs at the rib-to-stringer attachment in the areas specified in Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989; in accordance with Boeing Commercial Jet Nondestructive Test Manual, Chapter 51-00-00, Part 6, dated August 5, 1997.

Repetitive Inspections and Corrective Action

(e) If no crack is detected during any inspection required by either paragraph (c) or (d) of this AD, repeat the applicable inspection thereafter at intervals not to exceed 14,000 flight cycles.

(f) If any crack is detected during any inspection required by either paragraph (c) or (d) of this AD, prior to further flight, repair in accordance with Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989; or in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA Transport Airplane Directorate; 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 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. Repeat the applicable inspection thereafter at intervals not to exceed 14,000 flight cycles, following accomplishment of the repair.

Terminating Action

(g)(1) Accomplishment of the actions required by this AD constitutes terminating action for the inspections required by paragraph (a) of AD 94-07-08, as specified in Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989.

(2) Accomplishment of the structural modifications specified in either Boeing Service Bulletin 727-57-0127, Revision 2, dated February 13, 1976; or Revision 3, dated August 24, 1989; constitutes terminating action for the requirements of this AD.

Alternative Methods of Compliance

(h) 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, Transport Airplane Directorate. An alternative method of compliance that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO.

Note 2:

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

(i) Special flight permits may be issued in accordance with §§ 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

(j) Except as provided by paragraph (f) of this AD, the repairs shall be done in accordance with Boeing Service Bulletin 727-57-0127, Revision 3, dated August 24, 1989; as applicable. 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.

(k) This amendment becomes effective on May 16, 2000.