Airworthiness Directives; Boeing Model 767 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 767 series airplanes. This AD requires repetitive inspections to detect discrepancies of the wiring and surrounding Teflon sleeves of the fuel tank boost pumps and override/jettison pumps; replacement of the sleeves with new sleeves, for certain airplanes; and repair or replacement of the wiring and sleeves with new parts, as necessary. This amendment is prompted by reports of chafing of Teflon sleeves that surround and protect electrical wires inside conduits installed in the fuel tanks. The actions specified by this AD are intended to ensure adequate protection to the fuel pump wire insulation. Such chafing of the wire insulation could eventually result in exposure of electrical conductor, permit arcing from the wire to the conduit, and create a potential for a fuel tank fire or explosion.

DATES:

Effective July 6, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of July 6, 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 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:

Holly Thorson, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1357; 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 all Boeing Model 767 series airplanes was published in the Federal Register on November 15, 1999 (64 FR 61798). That action proposed to require repetitive inspections to detect discrepancies of the wiring and surrounding Teflon sleeves of the fuel tank boost pumps and override/jettison pumps; replacement of the sleeves with new sleeves, for certain airplanes; and repair or replacement of the wiring and sleeves with new parts, as 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

Two commenters support the proposed rule.

Credit for Inspections Accomplished Previously

One commenter requests that the FAA revise the proposed rule to clarify that airplanes inspected prior to the effective date of this AD in accordance with Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999, do not have to be inspected again until 60,000 flight hours or 30,000 flight cycles after the last inspection, whichever occurs first. The commenter states that there is no mechanism in the notice of proposed rulemaking (NPRM) to provide credit for inspections accomplished previously.

The FAA concurs with the intent of the commenter's request. Airplanes that have been inspected prior to the effective date of this AD in accordance with the referenced service bulletin should be inspected next according to the repetitive interval (60,000 flight hours or 30,000 flight cycles after the most recent inspection, whichever occurs first) specified in this AD. However, credit for applicable actions accomplished prior to the effective date of an AD is always provided by means of the statement in the body of the AD, “Compliance: Required as indicated, unless accomplished previously.” Therefore, no change to the final rule is necessary in this regard.

Revise Reporting Requirement

One commenter requests that the FAA revise paragraph (e) of the proposed rule to eliminate the requirement to include, in any report of positive inspection findings, “a statement indicating whether any wire has ever been removed and inspected during maintenance, along with the date (if known) of any such inspection.” The commenter states that it would be “virtually impossible” to meet this requirement, and only a review of maintenance records would show if a wire was inspected. Further, the commenter states that, because operators are only required to retain maintenance records for one year, a review of maintenance records would only show whether such an inspection was completed within the past year.

The FAA concurs with the commenter's request to revise the reporting requirement of this AD. As the commenter states, a review of maintenance records would be the most effective method for determining if wiring of the fuel tank boost pumps had previously been removed and inspected. The FAA also acknowledges that an operator may not have maintenance records extending back for more than one year for its airplanes. Therefore, the subject statement in paragraph (e) of this AD has been revised to specify that the report of positive inspection findings should include, “a statement indicating, if known, whether any wire has ever been removed and inspected during maintenance, along with the date (if known) of any such inspection.” However, the FAA expects that any available maintenance records will be thoroughly reviewed to determine if boost pump wiring has been removed and inspected previously.

Correct Typographical Error

One commenter requests that the proposed rule be revised to correct a typographical error. The commenter points out that “NOTE 1” of the NPRM refers to paragraph (e), but should refer to paragraph (f). The FAA concurs with the commenter's request, and “NOTE 1” of this final rule has been revised accordingly.

Consider Actions Accomplished in Accordance With AD 98-10-10

One commenter requests that the proposed rule be revised to exclude Model 767 series airplanes on which wiring and Teflon sleeving were replaced in accordance with the requirements of AD 98-10-10, amendment 39-10522 (63 FR 26063, July 13, 1998), provided that lacing ties were not installed on the outside of the sleeving (except at sleeve ends). The commenter points out that AD 98-10-10 requires a one-time visual inspection to confirm installation of Teflon sleeves over the electrical wires to the fuel tank boost pumps installed inside conduits in the main and center wing tanks of certain Boeing Model 767 series airplanes. The commenter states that it accomplished the inspection required by that AD on its entire fleet of Model 767 series airplanes and installed new wiring and Teflon sleeving through the conduits to the boost pumps in all locations. The commenter notes that it detected no damage during examination of the removed wiring.

The FAA partially concurs with the commenter's request. The FAA concurs with the commenter's summary of the requirements of AD 98-10-10 with respect to Model 767 series airplanes. However, this AD requires actions that differ from those required by AD 98-10-10. While AD 98-10-10 confirms the installation of the Teflon sleeves and requires additional inspections to detect chafing of wiring on airplanes on which Teflon sleeves are found to be missing, this AD requires inspection of the Teflon sleeves over the fuel pump wires to detect and correct damage or installation discrepancies. Therefore, the FAA finds that it would be inappropriate to reference AD 98-10-10 in establishing compliance with this AD. However, as provided in paragraph (f) of this AD, the commenter may request approval of actions accomplished in accordance with the requirements of AD 98-10-10 as an alternative method of compliance for the actions required by this AD. No change to the final rule is necessary in this regard.

Extend Inspection Compliance Time for Certain Airplanes

One commenter requests that the FAA revise the proposed rule to extend the initial compliance threshold for the inspection of Model 767 series airplanes having line numbers 721 and subsequent. The commenter states that the intent of Boeing Service Bulletin 767-28A0053, Revision 1 (which was referenced in the proposed rule as the appropriate source of service information for the proposed actions), has been incorporated during production on airplanes having line numbers 721 and subsequent, and any discrepancies (e.g., splices, cuts, splits, holes, worn areas, and lacing ties installed on the outside) of the Teflon sleeves surrounding the wiring of the fuel boost pumps and override/jettison pumps have been corrected.

The FAA concurs with the intent of the commenter's request. However, the manufacturer has been unable to verify that all of the actions recommended in Boeing Service Bulletin 767-28A0053, Revision 1, were accomplished during production on Model 767 series airplanes having line numbers 721 and higher. The FAA finds that it would be inappropriate to delay the issuance of this AD for identification of the line numbers on which the intent of the service bulletin was accomplished during production. However, as provided in paragraph (f) of this AD, once the correct line numbers have been identified, the commenter may request approval of actions accomplished during production as an alternative method of compliance for the actions required by this AD. No change to the final rule is necessary in this regard.

Revise Discussion Section Language

One commenter, the manufacturer, requests that the proposed rule be revised to remove the word “significant” from the following sentence in the “Discussion” section of the NPRM: “The inspections revealed significant chafing through the Teflon sleeves that enclose wire bundles inside the conduits located in the fuel tanks.” The commenter states that it has reviewed inspection results received from operators of Boeing Model 767 series airplanes, and the results show that no chafing through both layers of the Teflon sleeves or of the wiring inside the Teflon sleeves has been found.

The FAA does not concur with the commenter's request to not refer to the degree of chafing as “significant.” As stated previously, the FAA has issued AD 98-10-10, which requires a one-time visual inspection to confirm installation of Teflon sleeves over the electrical wires to the boost pumps installed inside conduits in the main and center wing tanks of certain Boeing Model 767 series airplanes. A review of the data from inspections accomplished in accordance with that AD revealed three instances of chafing through both layers of Teflon sleeves. Therefore, the FAA does consider chafing through the Teflon sleeves to be significant. However, the section of the proposal to which the commenter refers is not restated in this final rule; thus, no change to the final rule is necessary in this regard.

Credit for Inspections Accomplished Using Validation Service Bulletin

One commenter requests that the FAA revise paragraph (a) of the proposed rule to specify a compliance time of 36 months after the effective date of this AD for airplanes inspected previously in accordance with Boeing Service Bulletin 767-28A0053 “Preliminary.” The commenter states that the FAA should not require airplanes on which the proposed actions were accomplished in accordance with the preliminary service bulletin to be inspected again within 18 months after the effective date of this AD. The commenter asserts that Teflon sleeves inspected previously will not be worn within 18 months.

The FAA concludes that the “preliminary” service bulletin to which the commenter refers is the validation copy of Boeing Alert Service Bulletin 767-28A0053, dated May 21, 1998. The FAA does not concur with the commenter's request to provide credit for inspections accomplished in accordance with the validation copy of the service bulletin. The FAA finds that the validation copy did not provide instructions for inspecting or replacing the Teflon sleeves. Also, because the validation copy of the service bulletin was effective for only a small number of airplanes, the FAA finds that it would be inappropriate to complicate this AD by including specific instructions for airplanes inspected in accordance with that issue of the service bulletin. However, as provided in paragraph (f) of this AD, the commenter may request approval of inspections accomplished in accordance with the validation copy of the service bulletin as an alternative method of compliance with this AD. No change to the final rule is necessary in this regard.

Exempt Airplanes With Deactivated Center Fuel Tank

One commenter requests that the FAA revise the proposed rule to state that airplanes on which the center fuel tank is deactivated are not subject to the inspections specified in the proposed AD. The commenter states that it operates several Boeing Model 767 series airplanes on which the center fuel tank has been deactivated in accordance with certain Boeing service bulletins. The commenter states that the airplanes are configured with the override/jettison pumps' motor winding circuits opened at the P36 and P37 panels, and, with no power available to these wires, the possibility of arcing is eliminated. The commenter also requests that, if the FAA does not revise the proposed rule to exempt airplanes with the center fuel tank deactivated, paragraph (d) of the proposed rule be revised to state that, if the center fuel tank is deactivated, the test of the override fuel pumps must be accomplished prior to reactivation of the center fuel tank (rather than prior to further flight).

The FAA does not concur with the commenter's request to revise this AD to accommodate airplanes on which the center fuel tank is deactivated. The FAA acknowledges that it may not be necessary for operators to perform initial or repetitive inspections of the override/jettison fuel pump wiring on airplanes with deactivated center fuel tanks. However, as stated in NOTE 1 of the proposed rule (as well as the final rule), for airplanes that have been modified, altered, or repaired so that the performance of the requirements of the proposed rule is affected, the operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. No change to the final rule is necessary in this regard.

Explanation of Change in Service Bulletin Reference

In the NPRM, the FAA referred to Boeing Service Bulletin 767-28A0053, Revision 1, as an “alert” service bulletin. However, while the original issue of the service bulletin was considered an “alert” service bulletin, Revision 1 is not. Therefore, this final rule has been revised to remove the word “alert” from the service bulletin references throughout the AD.

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 described previously. 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 716 airplanes of the affected design in the worldwide fleet. The FAA estimates that 253 airplanes of U.S. registry will be affected by this AD. It will take approximately 5 work hours per airplane (for airplanes with jettison pumps) or 3 work hours per airplane (for airplanes without jettison pumps) to accomplish the required inspection/replacement, at an average labor rate of $60 per work hour. Parts, if required, will cost $336 for the sleeve replacement required by this AD. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $636 or $516 per airplane, if required to accomplish the replacement action; and $300 or $180 per airplane, per inspection cycle.

The cost impact figures discussed above are 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.

Regulatory Impact

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

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.

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

2000-11-06 Boeing: Amendment 39-11754. Docket 98-NM-316-AD.

Applicability: All Model 767 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 (f) 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 exposure of electrical conductor, which could permit arcing from the wire to the conduit and create a potential for a fuel tank fire or explosion, accomplish the following:

Inspections

(a) Perform a detailed visual inspection to detect discrepancies—including the presence of splices, cuts, splits, holes, worn areas, and lacing ties installed on the outside of the sleeves (except at the sleeve ends)—of the Teflon sleeves surrounding the wiring of the fuel tank boost pumps and override/jettison pumps, at the earlier of the times specified in paragraphs (a)(1) and (a)(2) of this AD, in accordance with Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999. Repeat the inspection thereafter at intervals not to exceed 60,000 flight hours or 30,000 flight cycles, whichever occurs first.

(1) Prior to the accumulation of 50,000 total flight hours, or within 90 days after the effective date of this AD, whichever occurs later.

(2) Within 18 months after the effective date of this AD.

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.”

Corrective Actions

(b) If any discrepancy is detected during any inspection required by paragraph (a) of this AD: Prior to further flight, remove the Teflon sleeves and perform a detailed visual inspection to detect damage of the wiring, in accordance with paragraph D. of the Accomplishment Instructions of Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999.

(1) If no damage to the wiring is detected, prior to further flight, install new Teflon sleeves in accordance with the service bulletin.

(2) If any damage to the wiring is detected, prior to further flight, accomplish the requirements of paragraph (c) of this AD.

(c) If any damage to the wiring is detected during any inspection required by paragraph (b) of this AD: Prior to further flight, perform a detailed visual inspection to determine if the wiring damage was caused by arcing, in accordance with paragraph D. of the Accomplishment Instructions of Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999.

(1) If the wire damage was not caused by arcing: Prior to further flight, repair any damaged wires or replace the wires with new or serviceable wires, as applicable, and install new Teflon sleeves; in accordance with the service bulletin.

(2) If any damage caused by arcing is found: Prior to further flight, perform an inspection for signs of fuel inside the conduit or on the wires, in accordance with the service bulletin.

(i) If no sign of fuel is found, accomplish the actions specified by paragraphs (c)(2)(i)(A), (c)(2)(i)(B), (c)(2)(i)(C), and (c)(2)(i)(D) of this AD.

(A) Prior to further flight, repair the wires or replace the wires with new or serviceable wires, as applicable, in accordance with the service bulletin.

(B) Prior to further flight, install new Teflon sleeves, in accordance with the service bulletin.

(C) Repeat the inspection for signs of fuel inside the conduit thereafter at intervals not to exceed 500 flight hours, until the requirements of paragraph (c)(2)(i)(D) of this AD have been accomplished. If any fuel is found inside the conduit during any inspection required by this paragraph, prior to further flight, replace the conduit with a new or serviceable conduit in accordance with the service bulletin. Thereafter, repeat the inspection specified in paragraph (a) of this AD at intervals not to exceed 60,000 flight hours or 30,000 flight cycles, whichever occurs first.

(D) Within 6,000 flight hours or 18 months after the initial fuel inspection specified by paragraph (c)(2) of this AD, whichever occurs first, replace the conduit with a new or serviceable conduit, in accordance with the service bulletin. Such conduit replacement constitutes terminating action for the repetitive fuel inspections required by paragraph (c)(2)(i)(C) of this AD.

(ii) If any fuel is found in the conduit or on any wire: Prior to further flight, replace the conduit with a new or serviceable conduit, replace damaged wires with new or serviceable wires, and install new Teflon sleeves; in accordance with the service bulletin. Thereafter, repeat the inspection specified in paragraph (a) of this AD at intervals not to exceed 60,000 flight hours or 30,000 flight cycles, whichever occurs first.

Pump Retest

(d) For any wire bundle removed and reinstalled during any inspection required by this AD: Prior to further flight after such reinstallation, retest the fuel pump in accordance with paragraph G., H., I., or J., as applicable, of the Accomplishment Instructions, of Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999.

Reporting Requirement

(e) Submit a report of positive inspection findings (findings of discrepancies only), along with any damaged wiring and sleeves, to the Seattle Manufacturing Inspection District Office (MIDO), 2500 East Valley Road, Suite C-2, Renton, Washington 98055-4056; fax (425) 227-1159; at the applicable time specified in paragraph (e)(1) or (e)(2) of this AD. The report must include the airplane serial number; the number of total flight hours and flight cycles on the airplane; the location of the electrical cable on the airplane; and a statement indicating, if known, whether any wire has ever been removed and inspected during maintenance, along with the date (if known) of any such inspection. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) 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.

(1) For airplanes on which the initial inspection required by paragraph (a) of this AD is accomplished after the effective date of this AD: Submit the report within 10 days after performing the initial inspection.

(2) For airplanes on which the initial inspection required by paragraph (a) of this AD has been accomplished prior to the effective date of this AD: Submit the report for the initial inspection within 10 days after the effective date of this AD.

Alternative Methods of Compliance

(f) 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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

(g) 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

(h) The actions shall be done in accordance with Boeing Service Bulletin 767-28A0053, Revision 1, dated April 1, 1999. 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

(i) This amendment becomes effective on July 6, 2000.