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727-100/200

AIRWORTHINESS LIMITATIONS (AWLs)

D6-8766-AWL

Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. 

Boeing also claims copyright in this document as a compilation and/or collective work.

This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the 

information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.

Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, 

MD-88, MD-90, and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document 

unless provided in writing by Boeing.

AUGUST 2010

COMPILED AND PUBLISHED BY:

MAINTENANCE PROGRAMS ENGINEERING

COMMERCIAL AVIATION SERVICES

BOEING COMMERCIAL AIRPLANE GROUP

SEATTLE, WASHINGTON

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TABLE OF CONTENTS

REVISIONS .................................................................................................................................................................................................................................. 9.0-5

LIST OF EFFECTIVE PAGES ...................................................................................................................................................................................................... 9.0-9

A. SCOPE....................................................................................................................................................................................................................................9.0-11

B. FUEL SYSTEMS AIRWORTHINESS LIMITATIONS...............................................................................................................................................................9.0-11

C. FUEL SYSTEMS AWL PAGE FORMAT................................................................................................................................................................................. 9.0-14

D. AIRWORTHINESS LIMITATIONS – FUEL SYSTEMS........................................................................................................................................................... 9.0-15

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REVISIONS

REVISION AND REVISION DESCRIPTION APPROVAL

MANAGER SEATTLE FAA AIRCRAFT

CERTIFICATION OFFICE, ANM-100S

March 2006 Original Release

Created new document to introduce Airworthiness Limitations 28-AWL-1 through 

28-AWL-15 which include inspections and design limitations to satisfy SFAR 88 requirements.

August 2007 Revised Section B, Airworthiness Limitations – Fuel Systems, to include revisions recommended by 

the Seattle FAA ACO. Replaced “FAA office that is responsible for the airplane model Type 

Certificate, or applicable regulatory agency” with “Seattle FAA ACO, or applicable regulatory 

agency”.

Revised Section B, Airworthiness Limitations - Fuel Systems, to include revisions recommended by 

the Seattle FAA ACO to clarify notification requirements surrounding short-term escalations and 

short-term extensions.

Revised the title of Section C to read "FUEL SYSTEMS AWL PAGE FORMAT" instead of “SYSTEM 

AWL PAGE FORMAT”.

Revised Airworthiness Limitation (AWL) Number 28-AWL-06 to add wire slack clearance distance 

(0.125") to the FQIS wire harness installation procedure.

Revised AWL Number 28-AWL-15 to add Ground Fault Interrupter (GFI) relays to the limitation that 

restricts resetting of fuel pump circuit breakers. Deleted verbiage regarding location of faults within 

fuel tanks because faults should be corrected regardless of location.

Added AWL Number 28-AWL-16, a yearly check of the Boost Pump GFI, applicable to airplanes 

that have incorporated Service Bulletin 727-18A0128.

Added AWL Number 28-AWL-17, a yearly check of the Boost Pump Uncommanded On System, 

applicable to airplanes that have incorporated Service Bulletin 727-28A130.

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August 2010 Revised Section B, Fuel Systems Airworthiness Limitations, to clarify the roles of SFAR 88 and 

§ 25.981 in the development of Airworthiness Limitation requirements.

Also revised the Use of Alternate Tools paragraph as requested by FAA Letter 140S-09-396 

dated November 23, 2009 to specify conditions for permissible use of alternate tools, test 

equipment, or materials.

Revised AWLs 28-AWL-01, 28-AWL-02, 28-AWL-07, 28-AWL-10, 28-AWL-11, 28-AWL- 12, 

28-AWL-13, 28-AWL-16, and 28-AWL-17 by replacing the word "per" with "refer to". Also 

standardized resistance value unit references and revised Applicability note for consistency.

Revised 28-AWL-01 to clarify the inspection area, and provided source documentation for 

performance of the procedures.

Revised 28-AWL-02 to clarify the inspection area and add a wiring inspection description.

Revised 28-AWL-03 by adding EME induced voltages to the concerns. Also specified that wiring 

within 6.5 inches of FQIS wiring is subject to this AWL, clarified wire spacing requirements, and 

added limitations for new wiring installation and for repair/replacement wiring.

Revised 28-AWL-04, 28-AWL-05, and 28-AWL-09 by clarifying the component vendor and 

applicable Component Maintenance Manual revisions.

Revised 28-AWL-06 to clarify the inspection area and the items associated with the procedural 

references. Revised and added items for verification in order to clarify the intent of the 

inspection and sealant type. Revised by replacing SWPM reference with instruction to contact 

Boeing for repair information as needed. 

Revised 28-AWL-07 by clarifying the design features, and replacing the following text: "0.005 

ohms (0.5 milliohms) or less" with "0.005 ohm (5 milliohms) or less" to correctly specify the 

numerical limit.

Revised 28-AWL-14 by limiting applicability to airplanes which have incorporated Service 

Bulletin [SB] 727-28A0132 but not SB 727-28A0133. Removed obsolete references to double 

wire sleeves, which are no longer used on boost pump wiring. Removed references to SB and 

FAA AD, and added AMM Reference 28-22-21 to clarify the intended procedures.

Revised 28-AWL-15 by adding AMM reference [28-22-00] to clarify the intended procedures.

Revised 28-AWL-17 to include full definition of acronym FOD as Foreign Object Debris and 

clarified the maintenance action for the auxiliary tank fuel boost pump system.

(Continued on next page)

Robert D. Breneman

Signature on File

08/16/2010

REVISION AND REVISION DESCRIPTION APPROVAL

MANAGER SEATTLE FAA AIRCRAFT

CERTIFICATION OFFICE, ANM-100S

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August 2010,

Continued

Added AWL Number 28-AWL-18, a 10 year check of the Fuel Quantity Indicating System (FQIS) 

- Out-Tank Wiring Lightning Shield to Ground Termination, applicable to all airplanes that have 

incorporated SB 727-28-0131.

Added AWL Number 28-AWL-19, instructions to check the FQIS - Out-Tank Wiring Lightning 

Shield to Ground Termination, applicable to all airplanes that have incorporated SB 727-28-

0131.

Added AWL Number 28-AWL-20, a 6 year check of the Fuel Boost Pump Wires in Conduit 

Installation - In Fuel Tank wire bundles in Fuel Tanks 1, 2, and 3, applicable to all airplanes that 

have incorporated SB Bulletin 727-28A0133.

Added AWL Number 28-AWL-21, for instructions to replace and check the Fuel Boost Pump 

Wires in Conduit Installation-In Fuel Tank, applicable to all airplanes that have incorporated 

SB 727-28A0133.

REVISION AND REVISION DESCRIPTION APPROVAL

MANAGER SEATTLE FAA AIRCRAFT

CERTIFICATION OFFICE, ANM-100S

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A. SCOPE

This section contains an FAA approved program of scheduled inspections and design limitations for operators to incorporate into their maintenance 

program for this type design to meet the new standards and assumptions introduced by § 25.981 and Special Federal Aviation Regulation SFAR No. 88. 

SFAR 88 – Fuel Tank System Fault Tolerance Evaluation Requirements and Title 14 Code of Federal Regulations § 25.981 – Fuel Tank Ignition 

Prevention require maintenance instructions, and control limitations for certain fuel tank critical design configurations. 

B. FUEL SYSTEMS AIRWORTHINESS LIMITATIONS

Paragraph 2(a) of SFAR 88 requires certain design approval holders of Type Certificates (TCs) and Supplemental Type Certificates (STCs) of large 

transport airplanes to conduct a safety review of the fuel tank systems. The purpose of the safety review is to identify design features that may result in 

development of ignition sources in the fuel tank systems. Fuel system Airworthiness Limitations (AWLs) are mandatory maintenance actions established in 

accordance with § 25.981 to ensure that unsafe conditions identified by the safety review do not occur or are not introduced into the fuel tank system as a 

result of configuration changes, repairs, alterations, or deficiencies in the maintenance program throughout the operational life of the airplane. An AWL 

may be an Airworthiness Limitation Instruction (ALI) or a Critical Design Configuration Control Limitation (CDCCL).

CDCCLs are a means of identifying certain design configuration features intended to preclude a fuel tank ignition source for the operational life of the 

airplane. CDCCLs are mandatory and cannot be changed or deleted without the approval of the Seattle FAA ACO, or applicable regulatory agency. A 

critical fuel tank ignition source prevention feature may exist in the fuel system and its related installation or in systems that, if a failure condition were to 

develop, could interact with the fuel system in such a way that an unsafe condition would develop without this limitation. Strict adherence to configuration, 

methods, techniques, and practices as prescribed is required to ensure compliance with the CDCCL. Any use of parts, methods, techniques or practices 

not contained in the applicable CDCCL must be approved by the Seattle FAA ACO, or applicable regulatory agency.

ALIs identify inspection tasks related to fuel tank ignition source prevention which must be done to maintain the design level of safety for the operational 

life of the airplane. These ALIs are mandatory and cannot be changed or deleted without the approval of the Seattle FAA ACO, or applicable regulatory 

agency. Strict adherence to methods, techniques and practices as prescribed is required to ensure the ALI is complied with. Any use of methods, 

techniques or practices not contained in these ALIs must be approved by the Seattle FAA ACO, or applicable regulatory agency.

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727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

USE OF ALTERNATE OR EQUIVALENT TOOLS, TEST EQUIPMENT OR MATERIALS

The Component Maintenance Manuals (CMM) listed in the AWLs are currently Seattle FAA ACO approved. If the CMM allows the use of alternate or 

equivalent tools, test equipment or materials, use of an alternate or equivalent tool, test equipment or material does not require further approval by the 

Seattle FAA ACO or local Regulatory Agency.

EXCEPTIONAL SHORT-TERM EXTENSIONS

Since AWL intervals are based on estimations of the probability of an event, an exceptional short-term extension for each fuel system AWL listed in this 

document may be made without jeopardizing safety. The local regulatory authority (e.g. a Principal Maintenance Inspector) must concur with any 

exceptional short-term extensions before they take place using procedures established with the local regulatory authority in the operators' manuals. The 

"exceptional short-term extension" process is applicable to AWL intervals. It should not be confused with the operator's "short-term escalation" program 

for normal maintenance tasks described in the operators' manuals and in the Flight Standards Handbook 8300.10. The Seattle FAA ACO has accepted 

that these exceptional short-term extensions may be granted without consultation with that office:

1. The term “exceptional short-term extension” is defined as an increase in a fuel system AWL interval that may be needed to cover an uncontrollable or 

unexpected situation. All AWLs listed in this section have been approved with an exceptional short-term extension of 30 days.

2. Repeated use of extensions, either on the same airplane or on similar airplanes in an operator's fleet, should not be used as a substitute for good 

management practices. Exceptional short-term extensions must not be used for fleet AWL extensions.

After a fuel system AWL has experienced an exceptional short-term extension, the AWL interval will revert back to its interval listed in this document. The 

Seattle FAA ACO must approve, prior to its use, any desired extension not explicitly listed above.

This exceptional short-term extension listed above applies to airlines that fall under the United States FAA jurisdiction only. Operators who are not under 

the U.S. FAA jurisdiction should obtain interval extension approvals from their local regulatory agency.

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REGULATORY AGENCY APPROVAL

Any deviations from the published AWL instructions included in this document require approval from the Seattle FAA ACO. This applies to operators 

under the U.S. FAA jurisdiction only and to airplanes registered in the U.S. All other operators should obtain approval from their own local regulatory 

agency for any deviations from the listed AWL instructions.

AWL REVISION PROCESS

In the event that an AWL is revised, Boeing will prepare a revision to this document that will be approved by the Seattle FAA ACO. This revision will then 

be forwarded to all 727 operators and the Seattle FAA ACO.

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727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

C. FUEL SYSTEMS AWL PAGE FORMAT

COLUMN EXPLANATION

AWL NUMBER Each task is given a unique AWL Item Number. The first and second digits are the ATA Chapter Number.

TASK ALI = Airworthiness Limitation Instruction. These tasks are inspections that should be performed at the listed intervals.

CDCCL = Critical Design Configuration Control Limitations

INTERVAL Task frequencies are specified in terms of a usage parameter such as flight hours, cycles or calendar time.

APPLICABILITY Airplane model applicability.

DESCRIPTION Description of the task to be performed or critical design configurations aspects that cannot be changed without violating 

the intent of the design.

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D. AIRWORTHINESS LIMITATIONS – FUEL SYSTEMS

AWL Number Task Interval Applicability Description

28-AWL-01 ALI 10 YRS/

36000 FC

NOTE

ALL External Wires Over Center Fuel Tank 

Concern: Potential for Wire chafing and arcing to Center Fuel Tank Upper Panel.

Perform a detailed inspection of the wire bundles routed over the center fuel tank and under the main 

deck floor boards between STA 740 – 870 to detect damaged clamps, wire chafing, and that the wire 

bundles are not in contact with the surface of the center fuel tank (refer to Boeing AMM 28-11-00). 

Repair any discrepancies found (refer to Boeing SWPM D6-54446, 20-10-11).

INTERVAL NOTE: Whichever comes first.

28-AWL-02 CDCCL N/A ALL External Wires Over Center Fuel Tank

Concern: Potential for wire chafing and arcing to Center Fuel Tank Upper Panel.

If any maintenance is performed in the area over the center fuel tank and under the main deck floor 

boards that affects the existing wiring or its installation, verify the following in the affected areas where 

the maintenance was performed:

1. Maintain the existing wire bundle routing and clamping.

2. Perform a detailed inspection of the wire bundles routed over the center fuel tank and under the 

 main deck floor boards in the affected areas where maintenance was performed to detect damaged

 clamps, wire chafing, and that the wire bundles are not in contact with the surface of the center fuel

 tank (refer to Boeing AMM 28-11-00). Repair any discrepancies found (refer to Boeing SWPM 

 D6-54446).

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28-AWL-03 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Out Tank Wiring Installation Separation Requirement

Concerns: Potential for hot shorts and EME induced voltages on the FQIS wiring to enter the fuel tank.

The following applies to any new wiring that is installed within 6.5 inches of FQIS wiring. New wiring is 

defined as any wiring that is added to the airplane, excluding repair or replacement of existing wiring.

1. Must use wire types BMS 13-48, BMS 13-60 or BMS 13-58.

2. The wiring must not be installed within a 2-inch radius of the FQIS wiring.

3. Under single failure of any clamp or bracket, a minimum 1/2 inch separation from FQIS wiring

 must be maintained.

 NOTE: Refer to the Wire Diagrams to identify FQIS wiring.

The following applies to repair or replacement of existing wiring that is installed within 6.5 inches of 

FQIS wiring:

1. Maintain existing wire routing and wire type.

 NOTE: Refer to the Wire Diagrams to identify FQIS wiring.

28-AWL-04 CDCCL N/A NOTE Fuel Quantity Indicating System (FQIS) – Indicator and Volumetric Top-Off (VTO) Unit Repair

Concern: Potential for maintenance error during FQIS Indicator or VTO Unit repair that may impact the 

original design of the FQIS Indicators and the VTO Unit, which limits the voltage, current and power 

into the tank, to preclude possible ignition source into the tank.

Repair and overhaul of FQIS Indicators and VTO units must be per Goodrich (V89305) Component 

Maintenance Manual (CMM) 28-41-01 Revision 12, CMM 28-41-03 Revision 3, CMM 28-41-07 

Revision 17, CMM 28-41-08 Revision 9, CMM 28-41-09 Revision H, CMM 28-41-10 Revision 6, 

CMM 28-41-23 Revision 10, CMM 28-41-42 Revision 4 or later revisions of these CMMs that have 

been approved by the Seattle FAA ACO. 

AIRPLANE NOTE: Applicable to airplanes with Volumetric Top-Off (VTO) installed.

AWL Number Task Interval Applicability Description

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28-AWL-05 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Repair of In-Tank Hardware (Tank Units and Compensators) 

Concern: Potential for maintenance error during repair of in-tank hardware (tank units and 

compensators). Arc gaps may develop that could result in an ignition source inside the fuel tank.

Repair and overhaul of FQIS tank units and compensators must be per Goodrich (V89305) 

Component Maintenance Manual (CMM) 28-40-03 Revision 5, CMM 28-40-25 Revision L, 

CMM 28-41-02 Revision 5, CMM 28-41-06 Revision 6, or later revisions of these CMMs that have 

been approved by the Seattle FAA ACO.

28-AWL-06 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Repair or Replacement of FQIS In-Tank Wire Harness

Concern: Potential for error during repair or replacement of FQIS in-tank wire harness. Arc gaps may 

develop that could result in an ignition source inside the fuel tank.

For repair and overhaul of FQIS in-tank wire harness, please contact Boeing.

Verify the following when installing the spar penetration receptacle (refer to Boeing AMM 28-41-21):

1. The mating surface of the tank wiring harness on the front spar is clean.

2. New O-ring(s) are installed.

3. The Jamnuts are torqued to 65-90 inch-pounds.

4. Sealant part number BMS 5-45 is installed around the perimeter of the in-tank harness connector 

 at the in-spar interface inside the tank.

AWL Number Task Interval Applicability Description

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727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

28-AWL-07 CDCCL N/A 727 airplanes that 

have incorporated 

Service Bulletin 

727-29A0067.

Lightning Protection – Hydraulic Line Fuel Tank Penetration 

Concern: Potential for arcing or sparking inside the tank at the interface between the bulkhead fitting 

and the spar during a lightning strike event.

The following design features must be maintained if the bulkhead fitting is removed and replaced

(refer to Boeing AMM 29-11-53 and 29-12-61):

1. Electrical fay surface bond from bulkhead fitting to structure outside the tank is 0.001 ohm

(1.0 milliohm) or less,

2. Fillet seal part number BMS 5-45 is installed on the fitting to the tank wall interface outside the tank,

3. Full bodied fillet seal part number BMS 5-45 is installed, encapsulating the fitting to the tank wall 

interface inside the tank, 

4. Electrostatic bonding jumper exists between the structure and the Hydraulic Heat Exchanger inside 

the tank.

5. Electrical bond from structure to the Hydraulic Heat Exchanger inside the tank is 0.005 ohm 

(5 milliohms) or less.

28-AWL-08 CDCCL N/A ALL Lightning, Fault Current, or Hot Short Protection – Fuel Tank Penetration

Concern: Potential for arcing or sparking inside the tank at a conductive metal-to-ground structure 

interface as a result of electrical fault currents or lightning strike events due to insufficient bonding 

within the ground electrical path.

Addition of any new penetrations to the fuel tanks (such as adding a bracket or bulkhead fitting or 

equipment) or change to the design features of the existing equipment penetrations (such as fuel 

measuring sticks, sump drain valves, fueling manifold, fuel temperature sensor, and motor operated 

fuel shutoff valve adaptor plate) requires approval by the Seattle FAA ACO.

28-AWL-09 CDCCL N/A ALL AC Electrical Fuel Tank Pump Maintenance

Concern: Potential for maintenance error during pump overhaul. Fuel pump designs contain ignition 

source prevention means (i.e., flame arrestor, thermal fuses, materials, leadwire retention means, etc.) 

that must be maintained if pump is overhauled.

Repair and overhaul of Fuel Pumps must be per Argo-Tech (V59875) CMM 28-20-1 Revision 7, 

CMM 28-20-5 Revision 6, or later revisions of these CMMs that have been approved by the Seattle 

FAA ACO.

AWL Number Task Interval Applicability Description

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28-AWL-10 CDCCL N/A ALL AC Fuel Pump Fault Current Fay Surface Bond Installation 

Concern: Potential for fault current path through the pump housing to structure inside the tank. 

Electrical faults internal to the fuel pump motor impeller are by design routed through the motor impeller 

assembly to the front face of the motor impeller assembly to structure outside the tank. The fay surface 

bond ensures that fault currents are conducted to structure outside the tank until the circuit breaker 

and/or GFI has had time to remove power from the pump.

The following features must be maintained during pump replacement (refer to Boeing AMM-28-22-21):

1. Pump fault current faying surface bond is 0.0002 ohm (0.2 milliohm) or less.

2. Motor Impeller bonding resistance to structure is 0.0002 ohm (0.2 milliohm) or less.

28-AWL-11 CDCCL N/A 727-100/200 

airplanes that 

have incorporated 

Service Bulletin 

727-28A0127.

Fueling Float Switch System Installation

Concern: Potential for wire chafing and arcing to conduit inside the tank. The Float Switch and Liner 

are not repairable to the initial manufactured standards.

During float switch replacement (refer to Boeing AMM 28-21-93), a new float switch assembly and liner 

system must be installed.

28-AWL-12 CDCCL N/A ALL

NOTE

Fuel Tank Access Doors – Lightning Protection Bond

Concern: Potential for arcing or sparking inside the tank at the interface between the door and the tank 

structure as a result of a direct strike or conducting currents through the wing skin.

The following features must be maintained during fuel tank access door installation (refer to Boeing 

AMM 28-11-21):

Verify presence of a phenolic strip positioned around the outermost periphery of the door that mates 

with the wing skin inside the tank,

Apply grease to both sides of the knitted aluminum mesh gasket, and

Install the greased knitted aluminum mesh gasket between the outside face of the door and the wing 

skin to establish the electrical conductivity between the access door and the wing skin using the Clamp 

Ring and fasteners torqued to that specified in the applicable Boeing AMM.

Note: Not applicable to machined Access Doors.

AWL Number Task Interval Applicability Description

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28-AWL-13 CDCCL N/A ALL Machined Fuel Tank Access Door Nos. 15 through 19 – Lightning Protection Bond

Concern: Potential for arcing or sparking inside the tank at the interface between the door and the tank 

structure as a result of a direct strike or conducting currents through the wing skin.

During machined fuel tank access door installation, perform the following actions (refer to Boeing 

AMM 28-11-21):

1. Clean the countersinks on the door.

2. For airplanes with a Pressure Relief Valve in the Surge Tank that have incorporated Service Bulletin

 727-28-0073:

 Maintain the electrical fay surface bond between the pressure relief valve and the door (1 ohm or

 less) if the valve is removed and replaced per Boeing AMM 28-13-11.

3. Install door using the same part number conductive fasteners and torque to that specified in

 the AMM.

28-AWL-14 CDCCL N/A 727 airplanes that 

have incorporated 

Service Bulletin 

727-28A0132, 

but have not 

incorporated 

Service Bulletin 

727-28A0133.

Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank

Concern: Potential for the boost pump wiring to chafe and arc in the conduit to provide an ignition 

source in the fuel tank.

The following design features must be maintained when replacing the boost pump wires (refer to 

Boeing AMM 28-22-21):

Wiring jacket and the Teflon sleeve part number TFE 2X are present and not chafed.

NOTE: The Teflon sleeve is not repairable. Whenever the wiring in conduit or the conduit is removed, 

a new Teflon sleeve must be installed (refer to Boeing AMM 28-22-21).

28-AWL-15 CDCCL N/A ALL Resetting Tripped Fuel Pump Circuit Breakers or Ground Fault Interrupters (GFIs)

Concern: Potential for arcing or sparking inside the tank between fuel pumps and fuel pump housings 

and outside the tank between pump wiring and structure in flammability leakage zones.

Verify it is safe to reset the circuit breaker(s) or GFI(s) by following the troubleshooting procedures 

(refer to Boeing AMM 28-22-00). Fault(s) that resulted in circuit breaker or GFI(s) relay trip must be 

isolated and corrected prior to reset.

AWL Number Task Interval Applicability Description

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28-AWL-16 ALI 1 YR 727 Airplanes that 

have incorporated 

Service Bulletin 

727-28A0128.

Boost Pump Ground Fault Interrupter (GFI)

Concern: Potential for pump housing burn-through, either internal or external to the fuel tank, as a 

result of major arcing due to electrical failure (i.e., damaged electrical connector, stator windings or lead 

wire to housing/end cap shorting).

The GFI is designed to detect electrical faults and open the circuit prior to pump housing burn through. 

The following maintenance check is required in order to ensure continued functionality of the 

GFI circuit.

Operationally check the GFI of all AC Fuel Tank Boost Pumps (refer to Boeing AMM 28-22-00).

28-AWL-17 ALI 1 YR 727 Airplanes that 

have incorporated 

Service Bulletin 

727-28A0130.

Auxiliary Tanks Boost Pump Uncommanded On System

Concern: Dry running the auxiliary tank fuel boost pumps may result in a single failure ignition source at 

the pump inlet. This failure may result from either frictional heating or sparking due to Foreign Object 

Debris (FOD) contact in the pump rotating elements, rotating elements contacting stationary parts, or 

hot journal bearings resulting from bearing contamination or failure.

The Pump Uncommanded On system provides an indication to the crew if the power to the auxiliary 

tank boost pumps has not been removed when the control switch is placed in the "Off" position.

Operationally check the auxiliary tank fuel boost pump uncommanded on system (refer to Boeing 

AMM 28-22-00).

AWL Number Task Interval Applicability Description

AUG 2010
D68766-AWL

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727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

28-AWL-18 ALI 10 YRS 727 Airplanes that 

have incorporated 

Service Bulletin 

727-28-0131

Fuel Quantity Indicating System (FQIS) – Out-Tank Wiring Lightning Shield to Ground Termination

Concern: Potential for Lightning induced voltages on the FQIS wiring to enter the fuel tank.

Perform the following functional check (loop resistance measurement) to ensure the integrity of the 

FQIS wiring shield to ground termination (refer to Boeing AMM 20-55-54):

1. Use a Loop Resistance Tester P/N 906-10246-2 or 906-10246-3 to measure and verify the

 resistance of the shield to ground termination for the following items:

(a) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector D578

(Left Main Tank No. 1) wire bundle W260.

(b) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector D580

(Center Tank No. 2) wire bundle W248.

(c) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector D582

(Right Main Tank No. 3) wire bundle W270.

(d) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector GD1902

(Wing Body Left) wire bundles W248/W260.

(e) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector GD1904

(Wing Body Right) wire bundles W270/W576.

(f) The loop resistance shall not exceed 40 milliohms (0.040 ohm) for Connector D4126J 

(P15 Refueling Panel) wire bundles W270/W576.

(Continued on next page)

AWL Number Task Interval Applicability Description

AUG 2010
727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

D68766-AWL

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28-AWL-18,

Continued

Fuel Quantity Indicating System (FQIS) – Out-Tank Wiring Lightning Shield to Ground Termination, 

Continued

2. For airplanes with Volumetric Top-Off (VTO) Units, use a Loop Resistance Tester P/N 906-10246-2

 or 906-10246-3 to measure and verify the joint resistance of the ground terminal to primary structure:

(a) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD4007S to 

structure (near D578 at Left main tank).

(b) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD4003S to 

structure (near D580) (Center tank).

(c) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD4013S to 

structure (near D582 at Right main tank).

(d) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD1902S to 

structure (Wing Body Left Disconnect).

(e) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD1904S to 

structure (Wing Body Right Disconnect).

(f) The joint resistance shall not exceed 1 milliohm (0.001 ohm) for ground terminal GD1908S to 

structure (P15 Refueling Panel).

AWL Number Task Interval Applicability Description

AUG 2010
D68766-AWL

BOEING PROPRIETARY - Copyright (c) - Unpublished Work - See title page for details Page 9.0-24

727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

28-AWL-19 CDCCL N/A 727 Airplanes that 

have incorporated 

Service Bulletin 

727-28-0131.

Fuel Quantity Indicating System (FQIS) – Out-Tank Wiring Lightning Shield to Ground Termination

Concern: Potential for Lightning induced voltages on the FQIS wiring to enter the fuel tank.

The following design features must be maintained if any FQIS out-tank wire bundle is replaced, wire 

bundle's shield is repaired, or shield path to ground is reconnected:

FQIS wiring shield to ground termination resistance must be maintained per AWL 28-AWL-18 (refer to 

Boeing AMM 20-55-54).

For airplanes that do not have Volumetric Top-Off (VTO) Units:

The following design features must be maintained if any of the following maintenance is performed on 

the out-tank wire bundles that disconnects or opens an FQIS wire bundle shield pigtail to ground path at 

the spar connector, refueling panel connector, or at the pressure seal:

(a) The wire bundle shield pigtail terminal lug to ground stud is removed and reinstalled.

(b) The wire bundle shield pigtail terminal lug is repaired or replaced.

(c) The ground stud is repaired or replaced.

Resistance from the pigtail or bonding strap terminal lug to the ground stud bracket must be no greater 

than 1.0 milliohm (0.001 ohm) (refer to Boeing SWPM 20-20-00).

NOTE: No bond check is required if the shield ground path is not disturbed.

AWL Number Task Interval Applicability Description

AUG 2010
727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

D68766-AWL

BOEING PROPRIETARY - Copyright (c) - Unpublished Work - See title page for details Page 9.0-25

28-AWL-20 ALI 6 YRS 727 airplanes that 

have incorporated 

Service Bulletin 

727-28A0133

Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank

Concern: Potential for the boost pump wiring to chafe and arc to the conduit resulting in an ignition 

source in the fuel tank.

Perform the following inspections for the boost pump wire bundle installations for Fuel Tanks 1, 2 and 3 

(W486, W488, W490, W492, W494, W496, W498 and W500):

1. Inspect the exposed convoluted liner and wiring where it exits the conduit at the front or rear spar 

and inside the boost pump housing.

(a) Inspect for any visible damage to the liner or wiring at the exit points of the conduit. If 

discrepancies are found, replace the liner. The wiring may be re-installed if it is not damaged 

(i.e., shield is not visible through the jacket) (refer to Boeing AMM 28-22-21).

(b) Inspect the tape and lockstitch ties where the wires exit the liner. Check that the tape and ties 

are intact and secure. Replace tape and lockstitch ties if found damaged or missing (refer to 

Boeing SWPM 20-10-11), and

(c) Inspect the clamps on the exposed liner at the front or rear spar and at the boost pump housing, 

to detect missing or broken clamps. If discrepancies are found, replace clamps (refer to Boeing 

AMM 28-22-21).

2. At the pump housing (refer to Boeing AMM 28-22-21): 

Verify electrical bonding resistance from the shield pigtail terminal lug to the boost pump housing

is 4 milliohms (0.004 ohm) or less (refer to Boeing SWPM 20-20-00), and

Verify electrical bonding resistance from the spare wire terminal lug to the boost pump housing is

4 milliohms (0.004 ohm) or less.

3. In the pressurized area:

Verify electrical bonding resistance from the terminal lug for the shield pigtail and spare wire to 

structure is 4 milliohms (0.004 ohm) or less (refer to Boeing SWPM 20-20-00).

AWL Number Task Interval Applicability Description

AUG 2010
D68766-AWL

BOEING PROPRIETARY - Copyright (c) - Unpublished Work - See title page for details Page 9.0-26

727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

28-AWL-21 CDCCL N/A 727 airplanes that 

have incorporated 

Service Bulletin 

727-28A0133

Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank

Concern: Potential for the boost pump wiring to chafe and arc to the conduit resulting in an ignition 

source in the fuel tank.

Service Bulletin 727-28A0133 incorporates convoluted liner and shielded wiring as protective features 

to the boost pump wiring for Fuel Tanks 1, 2 and 3 (W486, W488, W490, W492, W494, W496, W498

and W500).

If maintenance is performed that removes the boost pump wiring, conduit or liner, or if the shield pigtail 

or spare wire ground path is disconnected at the boost pump housing or inside the pressure seal, or if 

clamps to the liner are removed, then the following maintenance actions must be performed:

1. If the fuel boost pump conduit or shielded wires are removed and replaced or re-installed, or if the 

convoluted liner is removed and replaced, then the following maintenance actions must be 

performed (refer to Boeing AMM 28-22-21):

The wiring can be repaired if the repair remains outside of the conduit (refer to SWPM 20-10-13). 

Wiring may be re-installed in the conduit if it is not damaged (i.e., shield is not visible through the 

jacket). Use only wire type BMS13-60T07C04G018 if the wiring in the conduit is replaced. Use of 

any other wire types must be approved by the Seattle FAA ACO.

(a) The convoluted liner is not repairable. A new convoluted liner must be installed,

(b) The clamps on the convoluted liner at the front and rear spar and in the boost pump housing 

must be re-installed, 

(c) Tape and lacing ties must be applied to the wiring and liner where the wiring exits the liner at the 

front and rear spar and in the boost pump housing (refer to Boeing SWPM 20-10-11),

(Continued on next page)

AWL Number Task Interval Applicability Description

AUG 2010
727-100/200 AIRWORTHINESS LIMITATIONS (AWLs)

D68766-AWL

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28-AWL-21

Continued

Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank, Continued

(d) Measure the electrical bonding resistance from the shield pigtail terminal lug and of the spare 

wire terminal lug to the boost pump housing per Item 2 below, and

(e) Measure the electrical bonding resistance from the shield pigtail and spare wire terminal lug to 

structure in the pressurized area per Item 3 below if the wiring was replaced or re-installed.

2. If the terminal lug of the shield pigtail or the spare wire is disconnected and reconnected at the boost 

pump housing, then 

(a) Verify sealant is present between the terminal lug and boost pump bracket

(b) Measure the electrical bonding resistance after reconnecting to the boost pump housing (refer to 

Boeing AMM 28-22-21):

(i) Verify electrical bonding resistance from the shield pigtail terminal lug to the boost pump

 housing is 2.5 milliohms (0.0025 ohm) or less, unless the ground bracket is reworked. If

 the ground bracket is reworked, then verify the resistance from the shield pigtail terminal lug

 to the boost pump housing is 2 milliohms (0.002 ohm) or less (refer to Boeing SWPM 

 20-20-00), and

(ii) Verify electrical bonding resistance from the spare wire terminal lug to the boost pump

 housing is 2.5 milliohms (0.0025 ohm) or less, unless the ground bracket is reworked. If 

 the ground bracket is reworked, then verify the resistance from the spare wire terminal lug

 to the boost pump housing is 2 milliohms (0.002 ohm) or less.

3. If the terminal lug of the shield pigtail and spare wire is disconnected and reconnected in the 

pressurized area, then measure the electrical bonding resistance after reconnecting to the 

ground bracket:

(a) Verify electrical bonding resistance from the shield pigtail terminal lug to structure is 

2.5 milliohms (0.0025 ohm) or less, unless the ground bracket is reworked. 

(b) If the ground bracket is reworked, then verify the resistance from the shield pigtail terminal lug

to structure is 2 milliohms (0.002 ohm) or less (refer to Boeing SWPM 20-20-00).

4. Re-install clamps on the convoluted liner at the front and rear spar and in the boost pump housing

 if removed (refer to Boeing AMM 28-22-21).

AWL Number Task Interval Applicability Description

AUG 2010
D68766-AWL

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