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Proposed Rule

Airworthiness Directives; Boeing Model 767 Series Airplanes

Document Details

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Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 767 series airplanes, that currently requires a revision of the Airplane Flight Manual (AFM) to include procedures that will ensure that the center tank fuel pumps are not operated with less than 1,000 pounds of fuel in the center tank. This proposed AD would require a further revision of the AFM to specify conditions for minimum fuel weight requirements and procedures for ground transfer of fuel for certain airplanes, repetitive inspections to detect discrepancies of the center tank override/jettison fuel pumps, and replacement of any discrepant pump with a new or serviceable pump. This proposal would also require that any override/jettison pump that incorporates a configuration without a diffuser be restored to a configuration that incorporates a diffuser. This proposed AD would also require installation of a new configuration center tank fuel pump, which would terminate the AFM revisions regarding fuel system operating procedures and repetitive inspection requirements. This proposal is prompted by reports of cracks detected in the override/jettison fuel pump inlet diffuser. The actions specified by the proposed AD are intended to prevent ignition of fuel vapors due to the generation of sparks, to prevent a potential ignition source inside the fuel tank caused by metal-to-metal contact during dry fuel pump operation, and to ensure satisfactory fuel pump and fuel system operation.

DATES:

Comments must be received by October 2, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-226-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 98-NM-226-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.

Start Further Info

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.

End Further Info End Preamble Start Supplemental Information

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 Start Printed Page 50167in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 98-NM-226-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. 98-NM-226-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On September 11, 1997, the FAA issued AD 97-19-15, amendment 39-10136 (62 FR 48754, September 17, 1997). That AD is applicable to all Boeing Model 767 series airplanes, and requires a revision of the FAA-approved Airplane Flight Manual (AFM) to include procedures that will ensure that the center tank fuel pumps are not operated with less than 1,000 pounds of fuel in the center tank. That action was prompted by a report that an override/jettison fuel pump failed due to damage to an impeller unit and pumping unit housing caused by a loose diffuser ring in the fuel pump assembly. The requirements of that AD are intended to prevent ignition of fuel vapors due to the generation of sparks and a potential ignition source inside the fuel tank caused by metal-to-metal contact during dry fuel pump operation.

Other Relevant Rulemaking

Prior to issuance of AD 97-19-15, the FAA issued AD 94-11-05, amendment 39-8921 (59 FR 27970, May 31, 1994), which requires repetitive inspections of the pumping unit assembly on the override and jettison fuel boost pump assemblies, and either repair of the pumping unit assembly or replacement with a new assembly if any discrepancy was detected.

Actions Since Issuance of Previous Rules

Since the issuance of AD 97-19-15, cracks have been found in an override/jettison fuel pump inlet diffuser on a Boeing Model 767 series airplane. Subsequent inspection revealed that the screws connecting the inlet diffuser to the pump housing were still tight. The cracks, formed by high-cycle fatigue, likely were caused by a preload in the diffuser ring.

Also since the issuance of AD 97-19-15, an additional failure of a center tank fuel pump was reported. In this event, the screws connecting the inlet diffuser to the pump housing wore through the housing, liberating the diffuser.

Three occurrences of such center tank fuel pump damage have been noted on airplanes that were inspected in accordance with AD 94-11-05. The FAA also received two reports of fuel pumps with loose inlet diffuser screws in 1999, which were found during accomplishment of Boeing Alert Service Bulletin 767-28A0050.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 767-28A0050, dated December 18, 1997, and Revision 1, dated December 22, 1999. The alert service bulletin describes procedures for a visual inspection of the inlet diffuser assembly to detect cracks and determine whether the assembly is securely attached to the pump housing. The alert service bulletin also describes procedures for replacement of a discrepant pump with a new pump. The alert service bulletin also describes procedures for deactivating the center/auxiliary fuel tank on airplanes equipped with a center tank scavenge system, as an option to the inspection.

Boeing Alert Service Bulletin 767-28A0050 refers to Sundstrand Corporation Alert Service Bulletin 5006286-28-A8, dated October 10, 1997, as an additional source of service information for accomplishment of the inspection.

The FAA also has reviewed and approved Boeing Service Bulletin 767-28-0052, dated May 20, 1999, which describes procedures for the installation of an override/jettison fuel pump that has a new configuration (without the inlet diffuser). This service bulletin also describes procedures for the installation of placards at the airplane's fueling panel to prohibit the use of JP-4 and Jet-B fuels. Since approving Boeing Service Bulletin 767-28-0052 and the production equivalent change, the FAA has learned that the no-inlet diffuser fuel pump has shown output pressure fluctuations that have led to numerous fuel pump imbalance conditions.

The FAA has also reviewed and approved Boeing Alert Service Bulletin 767-28A0057, dated November 18, 1999, and Boeing Alert Service Bulletin 767-28A0059, dated December 22, 1999. These alert service bulletins provide instructions to install the diffuser assembly on center tank override/jettison pumps that had been previously configured without a diffuser assembly in accordance with Boeing Service Bulletin 767-28-0052, or the production equivalent.

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 supersede AD 97-19-15 to continue to require revising the AFM to include procedures that will ensure that the center tank override/jettison fuel pumps are not operated with less than 1,000 pounds of fuel in the center tank. The proposed AD also would require repetitive detailed visual inspections to detect discrepancies of the center tank override/jettison fuel pumps, replacement of any discrepant pump with a new or serviceable pump, and an alternative revision to the AFM to provide an optional procedure for maintaining a minimum amount of fuel in the center tank prior to flight when center tank fuel pumps are to be used. The proposed AD would require accomplishment of the inspection and replacement, as specified in Boeing Alert Service Bulletin 767-28A0050, Service Bulletin 767-28-0052, and Service Bulletin 767-28-0059; described previously, except as discussed below.

Differences Between Proposed AD and Relevant Service Information

Boeing Alert Service Bulletin 767-28A0050 limits its effectivity to Boeing Model 767 series airplanes having line numbers 001 through 672, and Boeing Alert Service Bulletin 767-28A0050, Revision 1, limits its effectivity to Boeing Model 767 series airplanes having line numbers 001 through 768. However, the FAA has determined that all Model 767 series airplanes are subject to the identified unsafe condition, and this proposed AD would apply to all Model 767 series airplanes.

Cost Impact

There are approximately 768 airplanes of the affected design in the worldwide fleet. The FAA estimates that Start Printed Page 50168299 airplanes of U.S. registry would be affected by this proposed AD.

The AFM revisions that are currently required by AD 97-19-15, and retained in this AD, take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $60 per airplane.

The AFM revisions that are proposed in this AD action would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the AFM revisions proposed by this AD on U.S. operators is estimated to be $17,940, or $60 per airplane.

The inspection that is proposed in this AD action would take approximately 3 or 6 work hours per airplane to accomplish (3 hours for airplanes not equipped with jettison fuel pumps, 6 hours for airplanes equipped with jettison fuel pumps), at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $180 or $360 per airplane, per inspection cycle.

Should an operator be required to install a center tank override/jettison fuel pump equipped with an inlet diffuser (as proposed by paragraph (g) or (h) of this AD), it would take approximately 5 work hours (per pump) per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact of the pump installation proposed by this AD on U.S. operators is estimated to be $300 per airplane.

Since the manufacturer has not yet developed a modification of the center tank override/jettison fuel pump commensurate with the actions proposed by this AD, the FAA is unable at this time to provide specific information as to the number of work hours or cost of parts that would be required to accomplish the proposed modification. A further problem in developing a specific cost estimate is the fact that modification costs are expected to vary from operator to operator and from airplane to airplane depending upon airplane configuration. The proposed compliance time of 24 months should provide ample time for the development, approval, and installation of an appropriate modification.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. Section 39.13 is amended by removing amendment 39-10136 (62 FR 48754, September 17, 1997), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 98-NM-226-AD. Supersedes AD 97-19-15, Amendment 39-10136.

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 (n)(1) 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 ignition of fuel vapors due to the generation of sparks and a potential ignition source inside the fuel tank caused by metal-to-metal contact during dry fuel pump operation, accomplish the following:

AFM Revisions: Alternatives

(a) Within 14 days after October 2, 1997 (the effective date of AD 97-19-15), accomplish the actions specified by either paragraph (b) or (c) of this AD.

Restatement of Requirements of AD 97-19-15

(b) Accomplish paragraphs (b)(1), (b)(2), (b)(3), and (b)(4) of this AD.

(1) Revise the Limitations Section of the FAA-approved Airplane Flight Manual

(AFM) to include the following procedures. This may be accomplished by inserting a copy of this AD in the AFM.

“If the center tank fuel pumps are to be used, there must be at least 5,000 pounds (2,267 kilograms) of fuel in the center tank prior to engine start.

The center fuel pumps must be selected 'OFF' at or greater than 1,000 pounds (453 kilograms) of fuel in the center tank. For airplanes not equipped with a center tank scavenge system, this 1,000 pounds (453 kilograms) of center tank fuel must be considered unusable.

Note:

On all Model 767-200ER/300ER series airplanes and some Model 767-200/300 series airplanes, a scavenge system, operating with fuel pressure from the main wing tank pumps, will operate automatically to transfer any fuel remaining in the center tank to the main tanks. Fuel transfer begins when the main tanks are approximately half empty.”

(2) Revise the Limitations Section of the FAA-approved AFM procedure titled “FUEL SYSTEM, FUEL USAGE II (fuel in center tank),” to include the following procedures. This may be accomplished by inserting a copy of this AD into the AFM.

“Use the center tank fuel for all operations with all operable fuel pumps ‘ON' and the cross feed valve(s) closed until the center tank fuel quantity is 1,000 pounds (453 kilograms) or greater, then use FUEL USAGE I.

Do not operate the center tank fuel pumps with less than 1,000 pounds (453 kilograms) of fuel in the center tank.

Note:

The crossfeed valve(s) is open for minimum fuel operation, and may be opened to correct fuel imbalance.”

(3) Revise the Normal Procedures Section of the FAA-approved AFM to include the Start Printed Page 50169following procedure. This may be accomplished by inserting a copy of this AD into the AFM.

“Use of Fuel From the Center Tank—When the center tank approaches ‘EMPTY' during normal use or fuel transfer, select both center tank fuel pump switches ‘OFF' with the first occurrence of any of the following:

  • The center tank fuel reaches 1,000 pounds (453 kilograms);
  • Either of the center tank fuel pump ‘PRESS' lights illuminate; or
  • Either the ‘CTR L FUEL PUMP' or ‘CTR R FUEL PUMP' EICAS message is displayed.”

(4) Revise the Non-Normal Procedures Section of the FAA-approved AFM to include the following procedures. This may be accomplished by inserting a copy of this AD into the AFM.

“Center Tank Fuel Pump Faults—A center tank fuel pump failure may have occurred if a fuel pump pressure light illuminates when there is ample fuel in the tank. If a fault is suspected, select the affected pump ‘OFF' and do not re-select ‘ON.' If the affected circuit breaker is tripped, do not reset. Select fuel crossfeed valve(s) ‘OPEN.'

Attempted operation of a faulted center tank pump could ignite fuel tank vapors in an empty or nearly empty tank.”

New Requirements of this Ad

(c) Accomplish the actions required by paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) of this AD. Following accomplishment of the requirements of these paragraphs, the AFM revisions required by paragraph (b) of this AD may be removed from the AFM.

(1) Revise the Limitations Section of the FAA-approved AFM to include the following procedures. This may be accomplished by inserting a copy of this AD in the AFM.

“If the center tank fuel pumps are to be used, there must be at least 5,000 pounds (2,267 kilograms) of fuel in the center tank when the entry doors are closed with the airplane readied for initial taxi.

The center fuel pumps must be selected ‘OFF' at or greater than 1,000 pounds (453 kilograms) of fuel in the center tank. For airplanes not equipped with a center tank scavenge system, this 1,000 pounds (453 kilograms) of center tank fuel must be considered unusable.

Note:

On all Model 767-200ER/300ER series airplanes and some Model 767-200/300 series airplanes, a scavenge system, operating with fuel pressure from the main wing tank pumps, will operate automatically to transfer any fuel remaining in the center tank to the main tanks. Fuel transfer begins when the main tanks are approximately half empty.”

(2) Revise the Limitations Section of the FAA-approved AFM procedure titled “FUEL SYSTEM, FUEL USAGE II (fuel in center tank),” to include the following procedures. This may be accomplished by inserting a copy of this AD into the AFM.

“Use the center tank fuel for all operations with all operable fuel pumps ‘ON' and the cross feed valve(s) closed until the center tank fuel quantity is 1,000 pounds (453 kilograms) or greater, then use FUEL USAGE I.

Do not operate the center tank fuel pumps with less than 1,000 pounds (453 kilograms) of fuel in the center tank.

Note:

The crossfeed valve(s) is open for minimum fuel operation, and may be opened to correct fuel imbalance.”

(3) Revise the Normal Procedures Section of the FAA-approved AFM to include the following procedure. This may be accomplished by inserting a copy of this AD into the AFM.

“Use of Fuel From the Center Tank—When the center tank approaches ‘EMPTY' during normal use or fuel transfer, select both center tank fuel pump switches ‘OFF' with the first occurrence of any of the following:

  • The center tank fuel reaches 1,000 pounds (453 kilograms);
  • Either of the center tank fuel pump ‘PRESS' lights illuminate; or
  • Either the ‘CTR L FUEL PUMP' or ‘CTR R FUEL PUMP' EICAS message is displayed.”

(4) Revise the Non-Normal Procedures Section of the FAA-approved AFM to include the following procedures. This may be accomplished by inserting a copy of this AD into the AFM.

“Center Tank Fuel Pump Faults—A center tank fuel pump failure may have occurred if a fuel pump pressure light illuminates when there is ample fuel in the tank. If a fault is suspected, select the affected pump ‘OFF' and do not re-select ‘ON.' If the affected circuit breaker is tripped, do not reset. Select fuel crossfeed valve(s) ‘OPEN.'

Attempted operation of a faulted center tank pump could ignite fuel tank vapors in an empty or nearly empty tank.”

Ground Transfer of Fuel

(d) For Model 767-200 and -300 series airplanes that are equipped with any override fuel pump having part number S343T002-5, -8, -12, or -15 (which are configured with machined inlet diffusers) and that are not equipped with a center tank scavenge system: For any period during which ground transfer of fuel is accomplished below 1,000 pounds (453 kilograms), accomplish the ground fuel pressure defueling actions specified by paragraphs (d)(1) and (d)(2), in accordance with the Boeing 767 Maintenance Manual Section 28-26-00, Pressure Defueling Procedures, titled “For Override Pumps with a Diffuser Installed.”

(1) Only one center tank pump may be operated, and that pump must be selected “OFF” at or greater than 400 pounds (200 kilograms), as indicated on the center tank fuel quantity indication system (FQIS), or at the first indication of a pump low pressure light.

(2) The pitch attitude of the airplane must be recorded prior to this procedure to verify that it is between −1 and +2 degrees. This may be accomplished by viewing the pitch inclinometer, located in the left main gear wheel well.

Repetitive Inspections

(e) For airplanes that are equipped with any override or jettison fuel pump having part number S343T002-5, -8, -12, or -15 (which are configured with machined inlet diffusers), except as provided by paragraph (f) of this AD: Within 60 days after the effective date of this AD, remove the override fuel pump and jettison fuel pump, as applicable, of the center tank, and perform a detailed visual inspection of the pump to detect discrepancies (cracking, screw movement, and diffuser movement), in accordance with Boeing Alert Service Bulletin 767-28A0050, dated December 18, 1997, or Revision 1, dated December 22, 1999. Repeat the inspection thereafter at intervals not to exceed 1,000 flight hours.

(1) If no discrepancy is detected, prior to further flight, reinstall the pump in accordance with the alert service bulletin.

(2) If any discrepancy is detected, prior to further flight, replace the pump with a new or serviceable pump, in accordance with the alert service bulletin.

Note 2:

Boeing Alert Service Bulletin 767-28A0050 refers to Sundstrand Alert Service Bulletin 5006286-28-A8, dated October 10, 1997, as an additional source of service information for accomplishment of the inspection required by paragraph (d) of this AD.

Note 3:

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.”

(f) For airplanes equipped with a center tank scavenge system: For any period during which the center fuel tank is deactivated in accordance with Boeing Alert Service Bulletin 767-28A0050, dated December 18, 1997, or Revision 1, dated December 22, 1999, the actions specified by paragraph (e) of this AD are not required.

Pump Replacement

(g) For airplanes that are equipped with any override fuel pump having part number S343T002-23, -51, -81, or -121 (which are configured WITHOUT inlet diffusers): Within 6 months after the effective dated of this AD, accomplish the actions specified by either paragraph (g)(1) or (g)(2) of this AD.

(1) Replace the override fuel pump with a fuel pump having a machined inlet diffuser installed, in accordance with Boeing Alert Service Bulletin 767-28A0057, dated November 18, 1999. Or

(2) Replace the override fuel pump with a fuel pump modified in accordance with paragraph (i) of this AD.

(h) For airplanes that are equipped with any jettison fuel pump having part number S343T002-23, -51, -81, or -121 (which are configured WITHOUT inlet diffusers): Within 6 months after the effective date of this AD, accomplish the actions specified by either paragraph (h)(1) or (h)(2) of this AD.

(1) Replace the jettison fuel pump with a fuel pump having a machined inlet diffuser installed, in accordance with Boeing Service Bulletin 767-28-0059, dated December 22, 1999. Or Start Printed Page 50170

(2) Replace the jettison fuel pump with a fuel pump modified in accordance with paragraph (i) of this AD.

Installation of Modified Pumps

(i) For all airplanes: Except as provided by paragraphs (g)(2) and (h)(2) of this AD, within 24 months after the effective date of this AD, install modified center tank override and jettison fuel pumps that are not subject to the unsafe condition described in this AD. The installation shall be accomplished in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

Terminating Action

(j) Accomplishment of the requirements of paragraph (e) of this AD constitutes terminating action for the requirements of AD 94-11-05, amendment 39-8921 (59 FR 27970, May 31, 1994).

(k) Accomplishment of the requirements of paragraph (i) of this AD constitutes terminating action for the requirements of paragraphs (a), (b), (c), (d), (e), (g), and (h) of this AD, and the requirements of AD 94-11-05, amendment 39-8921.

Spares

(l) As of the effective date of this AD, no person shall install on any airplane a fuel pump having part number S343T002-5, -8, -12, or -15, unless that pump has been inspected and corrective actions have been performed in accordance with the requirements of either paragraph (b) or (c), and paragraph (e), of this AD.

(m) As of the effective date of this AD, no person shall install on any airplane a fuel pump having part number S343T002-23, -51, -81, or -121.

Alternative Methods of Compliance

(n)(1) 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.

(2) Alternative methods of compliance, approved previously in accordance with AD 97-19-15, amendment 39-10136, are approved as alternative methods of compliance when performing the requirements of paragraphs (b) and (c) of this AD.

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 Permits

(o) 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.

Start Signature

Issued in Renton, Washington, on August 11, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 00-20966 Filed 8-16-00; 8:45 am]

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