747-400 MAINTENANCE PLANNING DATA

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747-400

MAINTENANCE PLANNING DATA (MPD) DOCUMENT

SECTION 9

AIRWORTHINESS LIMITATIONS (AWLs) AND

CERTIFICATION MAINTENANCE REQUIREMENTS (CM

D621U400-9

JUNE 2014

COMPILED AND PUBLISHED BY:

MAINTENANCE PROGRAMS ENGINEERING

COMMERCIAL AVIATION SERVICES

BOEING COMMERCIAL AIRPLANE GROUP

SEATTLE, WASHINGTON

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747-400 MAINTENANCE PLANNING DATA

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TABLE OF CONTENTS

REVISIONS .......................................................................................................................................................................................LIST OF EFFECTIVE PAGES ...........................................................................................................................................................A. SCOPE..........................................................................................................................................................................................B. AIRWORTHINESS LIMITATIONS (AWLS) – SYSTEMS...............................................................................................................

B.1 FUEL SYSTEM IGNITION PREVENTION ..............................................................................................................................

B.2 IMPACT-RESISTANT FUEL TANK ACCESS DOORS............................................................................................................B.3 NITROGEN GENERATION SYSTEM (NGS)..........................................................................................................................

C. AWLS – STRUCTURAL INSPECTIONS.......................................................................................................................................

C.1 LIMIT OF VALIDITY (LOV)......................................................................................................................................................

D. CERTIFICATION MAINTENANCE REQUIREMENTS (CMRs).....................................................................................................

E. REPORTING UNCONTROLLABLE HIGH THRUST FAILURE CONDITIONS .............................................................................

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REVISIONS

REVISION AND REVISION DESCRIPTION F

Revision 0 - January 1989Original Issue

Approved by: D

 (S

Revision 1 - February 1989Removed requirements to check for Operative bus between EEC and EIU one flight prior to 150 hour check and changed FADEC C2 check from 150 hours to 500 flight hours.

Approved by: D

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Revision 2 - June 1989Added requirements to accomplish a 1000 hour operational test which checks that air conditioning pack 3 high flow mode is disabled with lower lobe cargo compartment conditioned air on.Added requirements to interrogate the CMC for engine position 2 turbine overspeed failure message every 150 hours on RB211-524G or RB211-524G2.Revised requirements to check engine control system for Category 2 faults to 250 flight hours on RB211-524G or RB211-524G2.

Approved by: D

 (S

Revision 3 - June 1989Added requirement to Drain PW4000 Gearbox whenever cumulative oil addition totals 12 quarts.

Approved by: D

 (S

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747-400 MAINTENANCE PLANNING DATA

Revision 4 - June 1989Deleted CMR 22-Issue covered in FAA approved PW4000 Maintenance Manual via P&W Alert Service Bulletin PW4 ENG A79-39.

Approved by: D

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Revision 5 - August 1989Revised CMR 12 to include in operational test the E&E Cooling System Bypass Valve.Revised CMR 13 from an operational test of the E&E Cooling System Fan Check Valves to a detail visual inspection of the flapper doors and hinges.Added requirement to adjust/test the main deck air distribution shutoff valves on the Combi main deck fire protection system. 

Approved by: D

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Revision 6 - February 1991Revised CMR 3 RR effectivity to RR RB211-524 Series engines.Revised CMR 21 RR effectivity to RR RB211-524 series engines and excluded requirement to interrogate CMC for engine 2 TOS on RB211 powered 747-400s equipped with EICAS Version RR004.

Approved by: D

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Revision 7 - March 1992Revised CMR 1 task description to Operational (Short) Test - 115-Volt Standby Power Generation.Revised CMR 16 to limit applicability to 747-400’s equipped with stabilizer fuel capability.

Deleted CMR 21 because all RB211 powered 747-400s are now equipped with EICAS Software Version RR004 or a later version.

Approved by: D

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Revision 8 - November 1992Revised CMR 3 to change the 250 FH check for RR RB211 powered 747-400s to 500 FH in accordance with the updated Type Certificate Data Sheet (TCDS No. E30NE, Rev date: June 5, 1992).

Approved by: D

 (S

REVISION AND REVISION DESCRIPTION F

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Revision 9 - January 1993Revised CMR 3 to change the 500 FH check for GE CF6-80C2B1F powered 747-400s to 1000 FH in accordance with the FAA approved GE document GEK 98408, Rev. 6, dated September 1992.

Approved by: D

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Revision 10 - October 1993Revised CMRs 9, 10, 12, 14, and 15 to exclude the 747-400F due to addition of an E&E cooling system self-test design feature.Revised CMR 18 and 20 to exclude 747-400F model applicability.

Approved by: D

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Revision 11 - January 1994Revised CMR 6 to change the 1000 FH check for the E&E cooling system override mode function to 20,000 FH for the 747-400F.Revised CMR 13 to exclude the 747-400F model applicability.Revised CMR 20 to change the1000 FH check of the lower lobe cargo compartment conditioned air system to 7400 FH.Added 747-400 CMR-MPD/Task Card correlation list for reference.

Approved by: D

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Revision 12 - May 1994Revised CMR 3 to change the 500 FH check for the PW4000 engine to 1000 FH.

Approved by: D

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Revision 13 - June 1995Revised CMR 18 to revise the system description to note door #5 is not applicable on 747-400 Combi airplanes in the cargo mode and to add a note to the task which specifies check is required immediately after conversion 

to passenger mode.

Approved by: D

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REVISION AND REVISION DESCRIPTION F

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747-400 MAINTENANCE PLANNING DATA

Revision 14 - February 1997Revised CMR 18 to change the interval of part of the functional check procedure relating to the escape slide/raft packs from 30 months to 36 months. The remainder of the check retains the interval of 30 months.

Approved by: D

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Revision 15 - May 1998Revised CMR 3 to change the 1000 FH check for GE CF6-80C2B1F powered 747-400’s to 2000 FH in accordance with the FAA approved GE document GEK 98408, Rev 10, dated March 1996.Revised CMR 3 to change the 500 FH check for RR RB211 powered 747-400’s to 560 FH in accordance with the updated Type Certificated Data Sheet (TCDS No. E30NE).

Approved by: D

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Revision 16 - July 2001Revised CMR 8B to change the interval from 6000 FH to 10,000 FH based on revised High Lift System fault tree analysis.Revised CMR 9 and 10 to exclude 747-400F model applicability since the freighter airplane has the E/E Cooling automatic system self test which occurs every tenth landing.

Approved by: L

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Revision 17 - September 2002Added requirements to replace door strike assembly at four-year intervals.

Approved by: L

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Revision 18 - October 2002Added CMR 25 applicable only to airplanes incorporating any of these Boeing Service Bulletins 747-25-3306 and/or 747-25-3312. This amended type certificate complies with the new 14 CFR 25.795 and the amended 

14 CFR 25.772 as issued under Federal Register Docket No. FAA-2001-11032.

Approved by: L

 (S

REVISION AND REVISION DESCRIPTION F

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Revision 19 - February 2003Added CMR 26 applicable for line numbers 1320 and on except freighter models. This amended type certificate complies with the new 14 CFR 25.795 and the amended 14 CFR 25.772 as issued under Federal Register Docket No. FAA-2001-11032.

Approved by: L

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Revision 20 - March 2005Revised the format of MPD Section 9 to include the 747-400 Maintenance Planning Data (MPD) task references alongside each CMR task.Added standalone List of Effective Pages (LEP) to document.Added MPD Task Reference 52-051-08 to CMRs #24, #25 and #26.Revised MPD Item Numbers to reflect new item numbers as a result of transition to a new maintenance documentation publishing system.

Approved by: J

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Revision 21 - August 2005Revised MPD Section 9 to add Airworthiness Limitations section.Added Nitrogen Generation System AWL and CDCCL.Revised Scope and CMR description section to explain and clarify.

Approved by: (

Revision 22 - September 2005Revised MPD Section 9 to add Airworthiness Limitations Structures Inspection note for 747-400 Special Freighter.Revised Certification Maintenance Requirements section to reflect 747-400 Special Freighter incorporation.Revised MPD item number for CMR 8 and 20 to correct reference.Revised CMR 18, Note 2 to specify that the task be accomplished at 30 months rather than 36, whereas the remainder of the procedure can be performed at 36 months rather than 30. Revised procedure reference to 

remove E19 reference no longer required.

Approved by: J

 (S

REVISION AND REVISION DESCRIPTION F

JUN 2014
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Revision 23 - March 2006Added new Fuel System Airworthiness Limitations which include inspections and design limitations to satisfy SFAR88 requirements. Revised Airworthiness Limitation 47-AWL-01 to add missing Step 3, and AWL 47-AWL-03 to correct ATA reference.Revised CMR 10 AMM reference from 21-058-02 to 21-058-00 to correct reference.Revised CMR 20 MPD Item Number from 21-028-01 to 21-028-00 to correct reference.

Approved by: A

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Revision 24 - June 2006Revised tasks 47-AWL-01, 47-AWL-02, 47-AWL-03, 47-AWL-04, 47-AWL-05, 47-AWL-06 to correct airplane 

applicability.Revised 28-AWL-9 and 28-AWL-10 to clarify the intent of the inspection and to clarify the location of the bonding measurements.Deleted 28-AWL-21, because production incorporation and service bulletin release have been postponed indefinitely.Added 28-AWL-24 which mandates an inspection for the horizontal stabilizer fuel boost pump auto 

shutoff system.Added new reserve tank fueling valve CDCCL AWL Number 28-AWL-25.Revised 47-AWL-05 and 47-AWL-06 to add Interval Note.

Approved by: J

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November 2006Added a new operational check of the Main 2 and Main 3 override/jettison fuel pump uncommanded on system AWL Number AWL 28-AWL-26.

Approved by: J

 (S

REVISION AND REVISION DESCRIPTION F

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December 2006Revised CMR-24, CMR-25, and CMR-26 intervals from 4 years to 6 years to reflect improved reliability data for the Flight Deck Door Strike Assembly.

Approved by: J

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December 2006 R1Revised to add Airworthiness Limitation Structures Inspection Note for 747-400 Large Cargo Freighter (LCF).Revised CMRs 15, 16, 20, 23, 24, 25, 26 to exclude 747-400 LCF derivative. Revised CMR 2 to exclude cargo and APU fire/overheat detection system for 747-400 LCF. Revised CMR 18 to “only applicable to door 1 L/H” for 747-400 LCF.In Paragraph 1 of Section F, changed reference to 747 Supplemental Structural Inspection Document, D6-35022, Revision H to Revision G due to unknown release date for Revision H.Revised Airworthiness Limitations-fuel system section introduction to include revisions recommended by the Seattle FAA Flight Standards group.Revised airworthiness limitation number 28-AWL-24 to correct AMM procedure number from 28-22-00 to 28-17-00 and to revise line number in the applicability column from 1342 to 1343.

Added Motor Operated Valve actuator Airworthiness Limitation. This AWL is applicable to airplane Line Position 1382 and on, and airplanes modified per Service Bulletins 747-28A2292, and 747-28A2294. 

Approved by: J

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May 2007Added new CMR 27 to perform a functional check of the Reserve Tank 2 and 3 VTO Secondary Shut-off System for the 747-400 Large Cargo Freighter (LCF).

Approved by: J

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REVISION AND REVISION DESCRIPTION F

JUN 2014
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747-400 MAINTENANCE PLANNING DATA

October 2007Revised Section B. Airworthiness Limitations (AWLs) - Systems paragraph on Exceptional Short-Term 

Extensions for AWLs to clarify notification requirements.Revised the title of Section C to read “Page Format: Fuel Systems Airworthiness Limitations" instead of “Page Format: Fuel Tank System Airworthiness Limitation”.Revised AWL Number 28-AWL-19 to add Ground Fault Interrupter (GFI) relays to the limitation that restricts resetting of fuel pump circuit breakers. Added AWL Number 28-AWL-28, a yearly check of the Main Fuel Tank Boost Pump GFI, applicable to airplane Line Numbers 1394 and on and airplanes that have incorporated Service Bulletin 747-28A2261.Added AWL Number 28-AWL-29, a yearly check of the Center Wing Tank Electric Scavenge Pump GFI, applicable to airplanes with Electric Center Wing Tank Scavenge Systems, airplanes prior to Line Numbers 972 that have incorporated Service Bulletin 747-28A2261.Added Section G. Certification Maintenance Requirements (CMRs) - Exception Short-Term Extensions to clarify notification requirements.Revised CMR-24, CMR-25 and CMR-26 task interval from 6 years to 9 years to reflect improved reliability data 

for the Flight Deck Security Door.Added Paragraph “I” to incorporate “Reporting Uncontrolled High Thrust Failure Conditions” per FAR 121.703 and FAR 135.415.

Approved by: D

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November 2007Revised 28-AWL-25 bonding resistance value from 0.015 ohms to 0.0015 ohms to correct a typo. (The correct value is 1.5 milliohms).Revised CMR-27 to include Main Fuel Tanks 1 and 4 in VTO secondary shut-off system task for the 747-400 Large Cargo Freighter.

Approved by: P

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REVISION AND REVISION DESCRIPTION F

JUN 2014
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747-400 MAINTENANCE PLANNING DATA

FEBRUARY 2008Revised Paragraph F. AIRWORTHINESS LIMITATIONS (AWLs) - STRUCTURAL INSPECTIONS to add restriction for 747-400 Special Freighters delivered after January 11, 2008.

Approved by: R

 Je

MARCH 2008Revised Paragraph F. AIRWORTHINESS LIMITATIONS (AWLs) - STRUCTURAL INSPECTIONS to add restriction for 747-400 Large Cargo Freighter (LCF) delivered after January 11, 2008 and to change end date of December 1, 2007 to May 30, 2008 and add the text “appendix” per FAA letter dated July 16, 2007.Revised 28-AWL-01 by removing the 36000FH task interval limitation based upon engineering review and operator maintenance practice.Revised 28-AWL-03 to reflect the new maximum loop resistance values associated with the lightning protection 

of the unpressurized FQIS wire bundle installations so as to satisfy the Airworthiness Limitation Instructions required by SFAR 88. Also removed the joint resistance values and 36000FH task interval limitation based upon engineering review and operator maintenance practice.Revised 28-AWL-10 by removing the 36000FH task interval limitation based upon engineering review and operator maintenance practice.Revised 28-AWL-16 to change the term "grease" to "Corrosion Inhibiting Compound (CIC)" in Step 2 to reflect correct consumable type.Added AWLs 28-AWL-30, 28-AWL-31, and 28-AWL-32 to add the Electronic Fuel Level Indication System (EFLI) CDCCL requirement for the 747-400 (910K).

Approved by: D

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APRIL 2008Revised the Procedure Reference for CMR 27 to remove incorrect Task number and reflect the correct Page Block number.

Approved by: P

 (S

REVISION AND REVISION DESCRIPTION F

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747-400 MAINTENANCE PLANNING DATA

MARCH 2009Revised Paragraph F., AIRWORTHINESS LIMITATIONS (AWLs) - STRUCTURAL INSPECTIONS to remove operational limits on 747-400 airplanes converted to the Special Freighter configuration, as established for 

compliance to 14 CFR § 26.45 (c), and confer standards for continued compliance to the specifications of 747 Supplemental Structural Inspection Document, D6-35022.

Approved by: J

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DECEMBER 2009Revised 28-AWL-03 by adding maximum loop resistance values, associated with the lightning protection of the FQIS wire bundle installations, specific to the 747-400 LCF derivative. Also specified that the existing values are applicable to all 747-400 airplanes except 747-400 LCF, and clarified the wire bundle references as supplier part numbers. Also added conditional dependency of installation for resistance measurements of Connectors X01014 and X01015, and listed additional wire bundles associated with Connector X01014.Revised 28-AWL-11 to clarify component of concern as FQIS processor unit and identify the component manufacturer (Goodrich).Revised 28-AWL-12, 28-AWL-13, 28-AWL-18, and 28-AWL-32 to identify the component manufacturers.

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REVISION AND REVISION DESCRIPTION F

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747-400 MAINTENANCE PLANNING DATA

DECEMBER 2009, ContinuedRevised 28-AWL-14 to identify the component manufacturer (Goodrich) and correct Revision identification for Component Maintenance Manual 28-40-59 from "5" to "E".Revised 28-AWL-20 by adding note stating that the maintenance requirements are only applicable to areas that have been disturbed. Also clarified airplane applicability.Revised 28-AWL-22 by changing terminology in item references from "bonding strap" to "bonding jumper" to clarify the item of concern.Revised 28-AWL-23 by changing terminology in item references from "bonding strap" to "bonding jumper" to clarify the item of concern. Also corrected resistance limit from 0.25 milliohms to 2.5 milliohms and clarified airplane applicability.Revised 28-AWL-24 to note conditional dependency of Horizontal Stabilizer Fuel Boost Pump Automatic Shutoff System installation for AWL applicability. Also clarified airplane applicability.

Revised 28-AWL-31 to correct spelling of the acronym for Electronic Fuel Level Indication System (EFLI) and 

identify the component manufacturer (Parker).Revised 28-AWL-05, 28-AWL-25, 28-AWL-26, 28-AWL-27, and 28-AWL-28 to clarify the airplane applicability.Revised Section F., AIRWORTHINESS LIMITATIONS (AWLs) - STRUCTURAL INSPECTIONS to include notice 

of the additional and revised inspection requirements for 747-400 Large Cargo Freighter (LCF) airplanes imposed by Service Bulletins 747-00-2120 and 747-53A2817, respectively; updated the document reference for the 747-400 LCF Supplemental Structural Inspection Document, and removed operational limits on 747-400 LCF airplanes delivered after January 11, 2008, originally established for compliance to 14 CFR § 26.45 (c).

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REVISION AND REVISION DESCRIPTION F

JUN 2014
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747-400 MAINTENANCE PLANNING DATA

JULY 2010Revised introduction to Section E: Airworthiness Limitations - Nitrogen Generation System tasks to identify and update the FAA regulations corresponding to the compliance measures provided in the subsequent AWLs.Revised description for 47-AWL-01 by adding Service Bulletin specifications to the airplane applicability. Also 

added instructions and a note to clarify the procedure and parameters for the maintenance action.Revised 47-AWL-02 by changing the airplane applicability to add Service Bulletin specification and remove Line 

Numbers which are no longer affected.Deleted 47-AWL-03, 47-AWL-04, 47-AWL-05, and 47-AWL-06 because they are no longer applicable to the subject airplanes.Added AWL 47-AWL-07, a 25,000 Flight Hour inspection of the Nitrogen Enriched Air distribution ducting.Added AWL 47-AWL-08, a 25,000 Flight Hour check of the Nitrogen Generation Cross-Vent Check Valve.Added AWL 47-AWL-09, an identification of the maintenance standard for the Nitrogen Generation System and notice of potential future compliance requirements associated with decreased aircraft descent rates.

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NOVEMBER 2010Revised 47-AWL-07 and 47-AWL-08 by updating the Interval from 25,000 Flight Hours (FH) to 21,250 FH, based on updated analysis.

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JULY 2011Revised 47-AWL-02 to incorporate NGS performance features to show compliance with 14 CFR 26.33.

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OCTOBER 2011Added AWL 47-AWL-10, a 54,000 Flight Hour removal and replacement of the Thermal Switch.

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JULY 2012Added a new Section F.1 Limit of Validity (LOV) as required by Title 14 Code of Federal Regulations (CFR) Section 26.21 (Amendment 26-6).

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REVISION AND REVISION DESCRIPTION F

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AUGUST 2012Revised the title of Section B by adding “Fuel” and replaced the “Airworthiness Limitations - Fuel Systems” subheading with "Introduction" to be consistent with other Section 9 documents.Revised Section C, making it a subheading of Section B, to be consistent with other Section 9 documents.Revised Section D to become Section B.1, and revised the title from “Airworthiness Limitations – Fuel Systems” to “AWLs – Fuel System Ignition Prevention” to be consistent with other Section 9 documents.Added Section B.2, Impact-Resistant Fuel Tank Access Doors.Revised Section E, making it Section B.3 and replaced “Airworthiness Limitations – Nitrogen Generation System Tasks” with “AWLs – Nitrogen Generation System (NGS)”. Also added “Airworthiness Limitations – Nitrogen Generation System” subheading to be consistent with other Section 9 documents.Revised Section F and Section F.1, making it Section C and C.1 respectively and replacing the old Section F title from "Airworthiness Limitations (AWLs) - Structural Inspections" to "AWLs - Structural Inspections".Revised Section G, making it Section D and revised Section H, making it a subheading of Section D and revised 

the title to "CMR Tasks" to be consistent with other Section 9 documents.Revised the lettering of the remaining section to be sequential with the previous heading revisions.

SIG

JUNE 2014Revised Section A, Scope, to define FAA Oversight Office and replaced all references to "Seattle FAA ACO" with "FAA Oversight Office" throughout the entire document.Replaced the word "per" with "in accordance with" throughout the entire section except for the "per" in the AWL 28-AWL-20, 28-AWL-24, and 28-AWL-27 applicability. The word "per" in the AWL 28-AWL-23, 28-AWL-24, and 28-AWL-27 applicability was replaced with "that have incorporated".

References to FAA regulations were changed to include "Title 14 CFR §" to accurately reflect FAA regulation citations throughout the document and for consistency.The following revisions were made in Section B front matter:Replaced the first paragraph under "Introduction" with the information on FAA approved Airworthiness Limitations required under Title 14 CFR § 43.16 and § 91.403.Deleted the "Deviations From CMM or AMM Instructions" subheading.

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REVISION AND REVISION DESCRIPTION F

JUN 2014
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747-400 MAINTENANCE PLANNING DATA

JUNE 2014, ContinuedRevised the "Use of Alternate Tools" subheading to "Use of Alternate or Equivalent Tools, Test Equipment or Materials". Clarified that the use of alternate tools or equivalent tools, test equipment or materials not listed in the AWL requires approval from FAA Oversight Office. Also clarified that the CMM cited as "in accordance with" 

and not "refer to" are FAA approved and the alternate tools or equivalent tools, test equipment or materials not listed in the CMM require FAA Oversight Office approval.Deleted “For AWLS” from the "Exceptional Short-Term Extensions For AWLs" subheading. Changed references to "fuel system AWL" to "system AWL" to apply the front matter to all AWLs in Section B. Revised "(e.g., a Principal Maintenance Inspector)" to "or a Principal Maintenance Inspector" and the Flight Standards Handbook reference from "8300.10" to "8900.1 FSIMS".Added the "Accomplishment Instructions – General Information" section to clarify the use of "in accordance with" and "refer to" verbiage when referencing other Instructions for Continued Airworthiness documents and added reference to SWPM 20-20 for electrical bonding and grounding requirements.Added new subparagraphs "Definitions", to provide further clarification on accomplishment instructions, and "Supporting Documentation", to clarify that strict adherence to the methods, techniques and practices, as 

prescribed, is required to ensure the ALI or CDCCL is complied with.Revised the "Page Format: Fuel Systems Airworthiness Limitations" subheading to "Page Format: Systems Airworthiness Limitations" to apply the front mater to all AWLs in Section B.The following changes were made to Section B.1:Added "Amendment 25-102" to the Title 14 CFR § 25.981 regulations and a statement that the auxiliary tank comply with these regulations.Revised 28-AWL-07 to clarify when new repairs or alterations involving penetrations to the fuel tanks need to be reviewed by the FAA Oversight Office and added when a repair or alteration does not require additional FAA Oversight Office approval.Added 28-AWL-33 (ALI), Teflon Sleeving – Out-of-Tank Wire Bundle, for the inspection of Teflon sleeving and clamps around the wire bundle in clamp locations specified in Service Bulletin 747-57A2327 and 747-28A2324.Added 28-AWL-34 (CDCCL), Teflon Sleeving – Out-of-Tank Wire Bundle, to verify that the Teflon sleeving is not damaged around the wire bundle in clamp locations specified in Service Bulletin 747-57A2327 and 747-28A2324.

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REVISION AND REVISION DESCRIPTION F

JUN 2014
747-400 MAINTENANCE PLANNING DATA

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JUNE 2014, ContinuedAdded 28-AWL-35, Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank (for all airplanes that have incorporated SB 747-28A2306) for the verification of the conduit liner, Teflon sleeve, and jacketed and shielded wiring is installed when the pump wiring or wiring in the conduit is removed or replaced.Added 28-AWL-36, Fuel Boost Pump Wires In Conduit Installation – In Fuel Tank (for all airplanes that have incorporated SB 747-28A2204 but have not incorporated SB 747-28A2306) for the verification of the Teflon sleeve is installed when the pump wiring or wiring in the conduit is removed or replaced.Added 28-AWL-37, Lightning, Fault Current or Hot Short Protection Features – In Tank Sealant Requirements to require an inspection of the cap seals and fillet seals when maintenance is performed in the fuel tanks.

Revised 57-AWL-01 to add reference to Boeing AMM 28-11-02.The following revisions were made in Section C front matter:Revised the MRBR section references in the third paragraph to reflect the correct titles for the MRBR.

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REVISION AND REVISION DESCRIPTION F

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Section Page Date Section Page Date Section Page Date Section Page Date 

D621U400-9

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LIST OF EFFECTIVE PAGES

747-400 MAINTENANCE PLANNING DATA

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A. SCOPE

The scheduled maintenance requirements described in this section result from Model 747-400 airplane certification activities wi

Administration (FAA). Accordingly, this FAA approved Airworthiness Limitations (AWLs) and Certification Maintenance Require

cross-referenced in the Model 747-400 Type Certificate Data Sheet. These maintenance actions are mandatory. This Airworthiness Limitations Section is FAA-approved and specifies maintenance required under Title 14 Code of Federal Re

and § 91.403 of the Federal Aviation Regulations, unless an alternative program has been FAA approved.Where used in this document, the term “FAA Oversight Office” is defined as the FAA office that currently has oversight responsof the Boeing model 747-400. At the time of publication, the FAA office with oversight responsibility for the type certificate of thBoeing Aviation Safety Oversight Office (BASOO).AIRWORTHINESS LIMITATIONS (AWLs)The Airworthiness Limitations may only be revised with the approval of the FAA Oversight Office.If the inspections cannot be accomplished due to repairs and/or modifications, an alternate inspection acceptable to the FAA Obe used.CERTIFICATION MAINTENANCE REQUIREMENTS (CMRs)These scheduled maintenance tasks may only be revised by the FAA Oversight Office. Principal Maintenance Inspectors (locanot change these requirements or the intervals associated with these requirements.

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B. AIRWORTHINESS LIMITATIONS (AWLs) – SYSTEMS

INTRODUCTIONThe airplane systems maintenance requirements described in this AWL document result from various 747-400 airplane certifica

This Airworthiness Limitations section is FAA-approved and specifies maintenance required under Title 14 CFR § 43.16 and § 

Aviation Regulations, unless an alternative program has been FAA Oversight Office approved. The AWLs may only be revised FAA Oversight Office. If the maintenance requirements cannot be accomplished due to repairs and/or modifications, an alterna

the FAA Oversight Office, must be used.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 

airplane as required under Special Federal Aviation Regulation No. 88 (SFAR 88) – Fuel Tank System Fault Tolerance EvaluatTitle 14 CFR § 25.981 – Fuel Tank Ignition Prevention. CDCCLs are mandatory and cannot be changed or deleted without the 

Oversight Office. A critical fuel tank ignition source prevention feature may exist in the fuel system and its related installation or 

condition were to develop, could interact with the fuel system in such a way that an unsafe condition would develop without this to configuration, methods, techniques, and practices as prescribed is required to ensure compliance with the CDCCL. Any use 

techniques or practices not contained in the applicable CDCCL must be approved by the FAA Oversight Office. For each CDCincludes maintaining any installation during alterations; therefore, adherence to the CDCCL is required during maintenance or a

ALIs identify inspection tasks that must be done to maintain the design level of safety for the operational life of the airplane to pALIs are mandatory and cannot be changed or deleted without the approval of the FAA Oversight Office. Strict adherence to mpractices as prescribed is required to ensure the ALI is complied with. Any use of methods, techniques or practices not contain

approved by the FAA Oversight Office.

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REGULATORY AGENCY APPROVALAny deviations from the published AWL instructions included in this document require approval from the FAA Oversight Office. under the U.S. FAA jurisdiction only and to airplanes registered in the U.S. Operators who are not under the U.S. FAA jurisdictifrom their own local regulatory agency for any deviations from the listed AWL instructions.AWL REVISION PROCESSIn the event that an AWL is revised, Boeing will prepare a revision to this document that will be approved by the FAA Oversight 

then be forwarded to all 747-400 operators and the FAA Oversight Office.ACCOMPLISHMENT INSTRUCTIONS – GENERAL INFORMATIONThe listed AWLs may make reference to Instructions for Continued Airworthiness which are included in other Boeing document• When a document is cited using the words "in accordance with" in an airworthiness limitation, the cited document (or docum

to ensure that the critical design feature is maintained. Any deviation from the cited document requires FAA Oversight Offic

• When a document is cited using the words "refer to" in an airworthiness limitation, the cited document (or document section

complying with the airworthiness limitation. An alternative procedure may be developed by an operator in accordance with maintenance program/manual.

For electrical bonding and grounding requirements, refer to the Boeing Standard Wiring Practices Manual (SWPM) 20-20.

USE OF ALTERNATE OR EQUIVALENT TOOLS, TEST EQUIPMENT OR MATERIALSFor AWLs which require the use of certain tools, test equipment or materials, use of alternate or equivalent tools, test equipmen

approval from the FAA Oversight Office.The Component Maintenance Manuals (CMMs) listed in the AWLs as “in accordance with” and not “refer to” are currently FAA If the CMM allows the use of alternate or equivalent tools, test equipment or materials, use of an alternate or equivalent tool, tedoes not require further approval by the FAA Oversight Office.

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747-400 MAINTENANCE PLANNING DATA

EXCEPTIONAL SHORT-TERM EXTENSIONSSince AWL intervals are based on estimations of the probability of an event, an exceptional short-term extension for each syste

document may be made without jeopardizing safety. The local regulatory authority or a Principal Maintenance Inspector must cshort-term extensions before they take place using procedures established with the local regulatory authority in the operators' m

short-term extension" process is applicable to AWL intervals. It should not be confused with the operator's "short-term escalatimaintenance tasks described in the operators' manuals and in the Flight Standards Handbook 8900.1 FSIMS.The FAA Oversight Office has accepted that these exceptional short-term extensions may be granted without consultation with 1. The term “exceptional short-term extension” is defined as an increase in a system AWL interval that may be needed to cov

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

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

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

3. After a system AWL has experienced an exceptional short-term extension, the AWL interval will revert back to its interval lis

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

NOTE: This exceptional short-term extension listed above applies to airlines that fall under the U.S. FAA jurisdiction only. Op

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

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DEFINITIONSRemoved or Replaced: Defined as removal or replacement of a component, as well as partial removals.Disturbed: Defined as interference, movement or change to the arrangement or order of the referenced component.New wiring: Defined as any alteration that installs wiring that is added to the airplane after initial Airplane Airworthiness Certificdate that the MPD Section 9, D621U400-9, was first incorporated into an operator's maintenance program, whichever is later.Sealant: Defined as sealant type BMS 5-45 or equivalent in accordance with SRM 51-20-05 for inside of fuel tank, and sealant 

equivalent in accordance with SRM 51-20-05 for outside of the fuel tank.FAA Oversight Office: Defined as the FAA office that currently has oversight responsibility for the type certificate of the Boeing 

the time of publication, the FAA Oversight Office is the FAA BASOO.SUPPORTING DOCUMENTATIONStrict adherence to methods, techniques and practices as prescribed is required to ensure the ALI or CDCCL is complied with. manufacturer's maintenance procedures when performing maintenance that has an effect on an ALI or CDCCL. If operators do can increase the risk of an unsafe condition. Any use of methods, techniques or practices not contained in these ALIs or CDCC

the FAA Oversight Office.

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PAGE FORMAT: SYSTEMS AIRWORTHINESS LIMITATIONS

COLUMN EXPLANATIONAWL NUMBER Each task is given a unique AWL Item Number. The first and second digits are the ATA Chapter NumTASK ALI = Airworthiness Limitation Instruction. These tasks are inspections that should be performed at th

CDCCL = Critical Design Configuration Control Limitations

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

APPLICABILITY Airplane model applicability.DESCRIPTION Description of the task to be performed or critical design configurations aspects that cannot be change

the intent of the design.

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B.1 FUEL SYSTEM IGNITION PREVENTION

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

program for this type design to meet the new standards and assumptions introduced by Title 14 CFR § 25.981 and SFAR 88. SSystem Fault Tolerance Evaluation Requirements and Title 14 CFR § 25.981 – Fuel Tank Ignition Prevention require maintenan

limitations for certain fuel tank critical design configurations.NOTE: The auxiliary fuel tank installation has been shown to comply with Title 14 CFR § 25.981 at Amendment 25-102.

Paragraph 2(a) of SFAR 88 and Paragraph (b) of the standard introduced by Title 14 CFR § 25.981 (Amendment 25-102) requ

holders of Type Certificates (TCs) and Supplemental Type Certificates (STCs) of large transport airplanes to conduct a safety r

systems. The purpose of the safety review is to identify design features that may result in development of ignition sources in th

AWLs are mandatory maintenance actions required to ensure that unsafe conditions identified by the SFAR 88 safety review dintroduced into the fuel tank system as a result of configuration changes, repairs, alterations, or deficiencies in the maintenance operational life of the airplane.

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AWLs – FUEL TANK IGNITION PREVENTION

AWL Number Task Interval Applicability Description

28-AWL-01 ALI 12 YRS ALL External Wires Over Center Fuel Tank

Concern: Potential for chafing and arcing through center Fuel TPerform a detailed inspection of the bundles routed on main deunder the main deck floor boards in accordance with Boeing AMor loose clamps, wire chafing, and that the wire bundle is not in center fuel tank. If discrepancies are found, ensure wires are i

applicable wire installation drawings and repair in accordance wPractices Manual D6-54446.

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

Concern: Potential for wire chafing and arcing to center Fuel TIf any maintenance is performed in the area under the main decenter fuel tank, verify the following:1. Maintain the existing wire bundle routing and clamping.2. Installation of any new wire bundles must be in accordance 

Practices Manual D6-54446.

3. All wire bundles over the center fuel tank are inspected in a

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28-AWL-03 ALI 12 YRS ALL Fuel Quantity Indicating System (FQIS) – Out Of Tank Wiring L

Ground TerminationConcern: Potential for Lightning induced voltages on the FQIS Perform the following inspection to ensure the functional integrground termination in accordance with Boeing AMM 5-55-54:1. Visually inspect all connectors at the location being tested to 

includes connector plugs and backshells.

2. Use a Loop Resistance Tester, P/N 906-10246-2 or 906-10

the resistance of the shield to ground termination for the fol

The following applies to all 747-400 except 747-400 LarMajor Design Change:The loop resistance shall not exceed 40 milliohms for Conn

bundle supplier part number CN1036-151(Wing LE L/H DeThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-152 (Wing LE L/H DeThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-152 or -172 (Wing LE The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-151 or -171 (Wing LE The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-116 or -316 (Wing LE The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-117 or -317 (Wing LE The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-117, -317 or -327 (WThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-116, -316 or -326 (WThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-111 or -113 (Wing LE Sensor).The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-111 (Wing LE R/H M

(Continued on next page)

AWL Number Task Interval Applicability Description

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28-AWL-03

(Continued)

ALI 12 YRS ALL Fuel Quantity Indicating System (FQIS) – Out Of Tank Wiring L

Ground Termination (Continued)

The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-118, -318 or -518 (CeThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-112 or -312 (Center TThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-153 or -353 (Center The loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-115, -315 or -325 (WThe loop resistance shall not exceed 40 milliohms for Connbundle supplier part number CN1036-115, -315 or 325 (WiThe loop resistance shall not exceed 61 milliohms for Connbundle supplier part number CN1036-154, -354 or -554 (Hif installed).The loop resistance shall not exceed 59 milliohms for Connbundle supplier part number CN1036-119, -319, -519 or -7if installed).The following applies only to 747-400 Large Cargo FreChange:The loop resistance shall not exceed 24 milliohms for Connbundle supplier part number CN1036-351(Wing LE L/H DeThe loop resistance shall not exceed 22 milliohms for Connbundle supplier part number CN1036-352 (Wing LE L/H DeThe loop resistance shall not exceed 22 milliohms for Connbundle supplier part number CN1036-355 (Wing LE R/H DThe loop resistance shall not exceed 24 milliohms for Connbundle supplier part number CN1036-356 (Wing LE R/H DThe loop resistance shall not exceed 17 milliohms for Connbundle supplier part number CN1036-516 (Wing LE L/H MThe loop resistance shall not exceed 15 milliohms for Connbundle supplier part number CN1036-517 (Wing LE L/H M

(Continued on next page)

AWL Number Task Interval Applicability Description

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28-AWL-03

(Continued)

ALI 12 YRS ALL Fuel Quantity Indicating System (FQIS) – Out Of Tank Wiring L

Ground Termination (Continued)

The loop resistance shall not exceed 29 milliohms for Connbundle supplier part number CN1036-718 (Center Wing TaThe loop resistance shall not exceed 15 milliohms for Connbundle supplier part number CN1036-522 (Wing LE R/H MThe loop resistance shall not exceed 17 milliohms for Connbundle supplier part number CN1036-521 (Wing LE R/H MThe loop resistance shall not exceed 34 milliohms for Connbundle supplier part number CN1036-311 (Wing LE L/H MaThe loop resistance shall not exceed 34 milliohms for Connbundle supplier part number CN1036-313 (Wing LE R/H MThe loop resistance shall not exceed 27 milliohms for Connbundle supplier part number CN1036-557 (Center Tank DeThe loop resistance shall not exceed 28 milliohms for Connbundle supplier part number CN1036-515 (Wing LE L/H ReThe loop resistance shall not exceed 28 milliohms for Connbundle supplier part number CN1036-520 (Wing LE R/H R

28-AWL-04 CDCCL N/A ALL FQIS – Out Of Tank Wiring Lightning Shield to Ground Termina

Concern: Potential for Lightning induced voltages on the FQIS If any maintenance is performed on the FQIS wire bundle in thspar pressure seal, verify the following:1. Verify presence of shielded wiring.2. Verify the shield ground is terminated in accordance with Bo3. The installation is checked as specified in 28-AWL-03.

AWL Number Task Interval Applicability Description

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28-AWL-05 CDCCL N/A 747-400 airplanes 

Line Numbers 1272 

and on; 

or airplanes that 

have incorporated 

Service Bulletin 

747-29A2104.

Lightning Protection – Hydraulic Line Fuel Tank Penetration Concern: Potential for arcing or sparking inside the tank at the 

fitting and the spar during a lightning strike event.The following design features must be maintained in accordancthe bulkhead fitting is removed and replaced:1. Verify electrical fay surface bond between the hydraulic fittin

be 0.001 ohms or less.

2. Install fillet seal on the fitting to the tank wall interface outsid

3. Install full bodied fillet seal encapsulating the fitting to the ta

the tank.

4. Verify an electrostatic bonding jumper exists between the st

Heat Exchanger inside the tank.

5. Verify electrical bond from structure to the Hydraulic Heat E

0.005 ohms or less.

28-AWL-06 CDCCL N/A ALL AC Pump and DC Pump Maintenance

Concern: Potential for maintenance error during pump overhauignition source prevention means (i.e., flame arrestor, thermal f

retention means, etc.) that must be maintained if pump is overhRepair and overhaul of Fuel Pumps must be in accordance witComponent Maintenance Manual (CMM) Numbers 28-22-07 RRevision Number 3, 28-26-12 Revision Number 0, 28-26-14 RRevision Number 9, or later revisions of these CMMs that have Oversight Office.

AWL Number Task Interval Applicability Description

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28-AWL-07 CDCCL N/A ALL Lightning, Fault Current or Hot Short Protection – Fuel Tank Pe

Concern: Potential for arcing or sparking inside the tank at a cstructure interface as a result of electrical fault currents or lightinsufficient bonding within the ground electrical path.Any repair or alteration involving new or altered penetrations to with fasteners, adding a bracket, bulkhead fitting or equipmentfeatures of the existing equipment penetrations (such as fuel mvalves, fueling manifold, fuel temperature sensor, and motor opadaptor plate) requires approval from the FAA Oversight OfficeHowever, no additional FAA Oversight Office approval is requir

accomplished in accordance with:1. Structural Repair Manual procedures, and/or2. Boeing Service Bulletins, and/or3. Boeing ODA approved repair/alteration instructions;where all the required procedures that relate to the new or alterthe statement, "These data have been reviewed by the Boeing 

prevention requirements, and no further approval from the FAA satisfy the requirements of CDCCL 28-AWL-07 provided the re

accomplished in accordance with these instructions."Note: Electrical bonding of fittings and brackets and/or cap sea

sealing of component interface to structure inside and/or outsid

28-AWL-08 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Out Of Tank Wiring I

Requirement Concern: Potential for hot shorts and EMI induced voltages on tank to enter the fuel tank.Routing and installation of any new wiring must use wire types BMS 13 58, and not be within a 2-inch radius of the FQIS wirinseparation greater than 1⁄2 inch must be maintained from FQIS 

AWL Number Task Interval Applicability Description

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28-AWL-09 CDCCL N/A ALL Center Wing Tank Fueling Valve-Fault Current Bond

Concern: Potential for arcing or filament heating inside the cenThe following design features must be maintained in accordanwhen the center wing tank fueling valve is removed and replac1. Bonding jumper between the valve body and structure insid2. Measure the resistance from the valve body to the adjacent 

be 0.010 ohms (10 milliohms) or less.

The following design features must be maintained in accordanwhen the center wing tank refuel valve control unit is removed 

1. The bonding resistance from the exposed threads on the va

location), to the refuel valve control unit AND the bonding rethreads on the valve unit mounting stud (one location), to stmore than 0.010 ohms (10 milliohms).

This installation is checked as specified in 28-AWL-10.

28-AWL-10 ALI 12 YRS ALL Center Wing Tank Fueling Valve-Fault Current Bond

Concern: Potential for arcing or filament heating inside the cenThis installation includes the following checks in accordance w1. The bonding resistance from the exposed threads on the va

location), to the refuel valve control unit AND the bonding re

threads on the valve unit mounting stud (one location), to stmore than 0.010 ohms (10 milliohms).

28-AWL-11 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Fuel Quantity Proces

Concern: Potential for maintenance error during FQPU repair. the levels of energy, voltage, current, and power allowed within safe levels in order to preclude the potential of an ignition sour

Repair and overhaul of FQIS processor units must be in accordCMM 28-41-62 Revision 4, or later revisions of this CMM that hOversight Office.

AWL Number Task Interval Applicability Description

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28-AWL-12 CDCCL N/A ALL Single Point Sensor (SPS) Control Card Repair

Concern: Potential for maintenance error during SPS control cais designed to limit the levels of energy, voltage, current, and pcircuit to intrinsically safe levels in order to preclude the potentany fuel tank.Repair and overhaul of Single Point Sensor Control Card must Data Systems (V58880) CMM 28-21-02 Revision 2, or later rev

been approved by the FAA Oversight Office.Note: Ragen Data Systems is now Vibro-Meter Inc.

28-AWL-13 CDCCL N/A All 747-400 with HST Remote Electronic Unit (REU) Repair

Concern: Potential for maintenance error during REU repair. Tlevels of energy, voltage, current, and power allowed within the levels in order to preclude the potential of an ignition source wi

Repair and overhaul of REU must be in accordance with Good

Revision 4, or later revisions of this CMM that have been approOffice.

28-AWL-14 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Repair of In-Tank Ha

Densitometers, and Compensators) Concern: Potential for maintenance error during repair of in-tancompensators and densitometers). Arc gaps may develop thasource inside the fuel tank.Repair and overhaul of FQIS tank units, compensators, and deaccordance with Goodrich (V89305) CMM 28-40-55 Revision 6

Revision E, or later revisions of these CMMs that have been apOffice.

AWL Number Task Interval Applicability Description

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28-AWL-15 CDCCL N/A ALL Fuel Quantity Indicating System (FQIS) – Repair of In-Tank Wi

Concern: Potential for error during repair or replacement of in-tadevelop that could result in an ignition source inside the fuel taRepair and overhaul of FQIS in-tank wire harness must be in a20-14-12.Installation of FQIS in-tank wire harness must be in accordancVerify the following when installing spar penetrations in accord

28-41-09:1. A new O-ring is installed in the groove of the FQIS wire bun2. The spar connector and the mating surface are clean3. The connector jamnut is tightened to a torque of 200-250 inVerify the following when installing the applicable airplane wire wire harness spar penetration:1. The coupling connector is tightened to a torque of 60-70 inc2. The between the bonding jumper on the airplane wire bund

structure is not more than 0.0005 ohm (0.5 milliohms) for H(10 milliohms) for all other tanks.

28-AWL-16 CDCCL N/A ALL Fuel Tank Access Doors Configuration

Concern: Potential for arcing or sparking inside the tank at the the tank structure as a result of a direct strike or conducting cuThe following must be maintained during fuel tank access door 28-11-02, 28-11-03): NOTE: Not applicable to center wing tank access door.1. Verify presence of a molded rubber seal positioned around t

door that mates with the wing skin inside the tank.

2. Apply Corrosion Inhibiting Compound (CIC) to both sides of 

gasket, and

3. Install the knitted aluminum mesh gasket between the outsi

wing skin to establish the electrical conductivity between the wing skin.

AWL Number Task Interval Applicability Description

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28-AWL-17 ALI 18 months ALL Fault Current Detector for CWT and Inboard Main Tank Overrid

HST Transfer Fuel PumpsConcern: Potential burn through of pump case in the event of efuel pumps.Verify the following in accordance with Boeing AMM 28-31-14 fpumps, 28-17-14 for HST transfer pumps.The ground fault detector for each pump is working properly.Use Fault Current Detector Test as specified in AMM.

28-AWL-18 CDCCL N/A ALL Fault Current Detectors Repair CMM

Concern: Potential for maintenance error during Fault Current may be introduced to pumps creating an ignition source.Repair and overhaul of Fault Current Detectors must be in accoCMM 28-31-22 Revision 4, or later revisions of this CMM that hOversight Office.

28-AWL-19 CDCCL N/A ALL Resetting Tripped Fuel Pump Circuit Breakers or Ground Fau

Concern: Potential for arcing or sparking inside the tank betwehousings and outside the tank between pump wiring and struc

zones.Verify it is safe to reset the circuit breaker(s) or GFI(s) by follo

troubleshooting procedures. Fault(s) that resulted in circuit brbe isolated and corrected prior to reset.

AWL Number Task Interval Applicability Description

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747-400 MAINTENANCE PLANNING DATA

28-AWL-20 CDCCL N/A 747-400 airplanes 

Line Numbers 1284 

and on; 

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2239 or 

747-28A2245.

Lightning Protection – Engine Fuel Feed Line Fuel Tank PenetConcern: Potential for arcing, sparking or filament heating insibetween the bulkhead fitting and the spar during a lightning strThe following must be maintained in accordance with Boeing Afitting or attached tubing are removed and replaced (Note: Eacapplicable if the subject area has been disturbed):Verify electrical fay surface bond between the bulkhead fitting ainside the tank must be 0.0005 ohms (0.5 milliohms) or less.Install full-bodied fillet seal encapsulating the bulkhead fitting to 

the tank.Install full-bodied fillet seal encapsulating the first coupling inteVerify an electrostatic bonding jumper presence between the stwith the bulkhead fitting inside the tank.Verify the electrical bond from structure to first tube mating with 

0.010 ohm (10 milliohms) or less.

28-AWL-21 Reserved for future SFAR 88 AWL.

AWL Number Task Interval Applicability Description

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28-AWL-22 CDCCL N/A ALL AC Fuel Pump Fault Current Bonding Path

Concern: Potential for fault current path through the pump housElectrical faults internal to the fuel pump motor impeller are by dimpeller assembly to the bonding jumpers on the front face of tstructure outside the tank. The bonding jumpers ensure that fastructure outside the tank until the circuit breaker and/or GFI hafrom the pump.The following features must be maintained during pump replacBoeing AMM 28-22-03:For Hydro-Aire Pumps:1. The presence of two bonding jumpers.2. The motor impeller bonding resistance across the jumpers t

not more than 0.0002 ohms (0.2 milliohms). The motor impe

across the jumpers to structure for horizontal stabilizer tank 

pumps is not more than 0.0004 ohms (0.4 milliohms).

For FR-HITEMP Pumps:1. The presence of one bonding jumper.2. The motor impeller bonding resistance across the jumpers t

not more than 0.0002 ohms (0.2 milliohms).

3. The motor impeller bonding resistance across the jumpers t

boost pumps is not more than 0.0005 ohms (0.5 milliohms).

AWL Number Task Interval Applicability Description

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747-400 MAINTENANCE PLANNING DATA

28-AWL-23 CDCCL N/A 747-400 airplanes 

Line Numbers 1368 

and on; 

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2266 and 

(if applicable) 

747-28A2267.

Fuel Quantity Indicating System (FQIS) – Installation of Center Protector (HSP)Concern: Potential for wire to wire hot short voltages on the cedensitometer wiring to enter the fuel tank. This is applicable to 

densitometer installed.The FQIS HSP is designed to prevent wire to wire external hot fuel tank where it may cause an ignition. The following features must be maintained during replacement 

Boeing AMM 28-41-24:1. Verify the bonding jumpers are installed in accordance with 2. Verify the bonds from the HSP to stiffeners where the bond

are equal to or less than 0.0025 ohms (2.5 milliohms).

3. A new unit must be used.The Hot Short Protector unit is not repairable.

28-AWL-24 ALI 1 YR 747-400 airplanes 

Line Numbers 1343 

and on with HST 

installed; 

or airplanes that 

have incorporated 

Service Bulletin

747-28A2262.

Horizontal Stabilizer Fuel Boost Pump Automatic Shutoff Syste

Concern: Dry running the horizontal stabilizer tank fuel pumps 

failure ignition sources developing at the pump inlet due to eithas a result of FOD contacting the pump rotating elements, rotastationary parts, or hot journal bearings due to bearing contamThe automatic shutoff system is installed and designed to limit c

to 15 seconds.The following test is required in order to protect against latent fFunctionally check the horizontal stabilizer tank fuel boost pumaccordance with Boeing AMM 28-17-00.

AWL Number Task Interval Applicability Description

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

28-AWL-25 CDCCL NA 747-400 airplanes 

Line Numbers 1378 

and on;

or airplanes that 

have incorporated 

Service Bulletin

747-28A2291.

Reserve Tank Fueling Valve-Induced Lightning Protection BondConcern: Potential for arcing or filament heating inside the cenfuel tank.The following design features must be maintained in accordanwhen the reserve tank fueling valve controller is removed and 1. Two bonding jumpers between the valve controller and stru2. The bonding resistance from the mounting bolt to structure 

0.0015 ohms (1.5 milliohms).

28-AWL-26 ALI 1 YR 747-400 airplanes 

Line Numbers 1380 

and on;

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2280.

Main Tank 2 and Main Tank 3 Override/Jettison Fuel Pump UnConcern: Dry running the main 2 and main 3 tank fuel override/for single failure ignition sources developing at the pump inlet dsparking as a result of FOD contacting the pump rotating elemcontacting stationary parts, or hot journal bearings due to bearPerform an operational test of the main 2 and main 3 override/juncommanded on system in accordance with Boeing AMM 28-

AWL Number Task Interval Applicability Description

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

28-AWL-27 CDCCL NA 747-400 airplanes 

Line Numbers 1382 

and on;

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2292 and 

747-28A2294.

Fault Current Protection - Motor Operated Valve (MOV) ActuatConcern: Potential for arcing or sparking inside the fuel tank at structure interface as a result of electrical fault current event.The following design features must be maintained in accordanc28-14-21, 28-14-31, 28-14-41, 28-14-61, 28-16-01, 28-16-04, 228-22-02, 28-25-02, 28-31-04, and 28-31-05.I. If the MOV actuator is mounted to the spar with an adapter p

1. Maintain the following if the adapter plate is removed and 

a. Verify electrical fay surface bond resistance between t

0.0005 ohms (0.5 milliohms) or less.

b. Install fay surface seal between the adapter plate and c. Cap seal the four bolts that attach the adapter plate to t

seal around the edge of the hole and on the stationary the tank.

d. Install sealed electrical fay surface bond and fay surfac

mating surfaces of the index plate and the adapter plat

e. Install sealed electrical fay surface bond and fay surfac

surfaces of the actuator and the index plate.

f. With the bonding jumper not installed, verify electrical 

actuator mounting feet and the spar is 0.0025 ohms (2

g. Prior to attachment of the bonding jumper to the actua

resistance between the loose end of the bonding jump

(1.5 milliohms) or less.

h. Attach the bonding jumper to the actuator bonding tab 

surface bond. 

 (Continued on next page)

AWL Number Task Interval Applicability Description

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

28-AWL-27 CDCCL NA 747-400 airplanes 

Line Numbers 1382 

and on;

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2292 and 

747-28A2294.

Fault Current Protection - Motor Operated Valve (MOV) Actuat

2. Maintain the following if the index plate is removed and re

a. Install sealed electrical fay surface bond and fay surfac

mating surfaces of the index plate and the adapter plat

b. Install sealed electrical fay surface bond and fay surfac

surfaces of the actuator and the index plate.

c. With the bonding jumper not installed, verify electrical 

actuator mounting feet and the spar is 0.0025 ohms (2

d. Prior to attachment of the bonding jumper to the actua

resistance between the loose end of the bonding jump

(1.5 milliohms) or less.

e. Attach the bonding jumper to the actuator bonding tab 

surface bond.

3. Maintain the following If the MOV actuator is removed and 

a. Install sealed electrical fay surface bond and fay surfac

surfaces of the actuator and the index plate.

b. With the bonding jumper not installed, verify electrical 

actuator mounting feet and the spar is 0.0025 ohms (2

c. Prior to attachment of the bonding jumper to the actua

resistance between the loose end of the bonding jump

(1.5 milliohms) or less,

d. Attach the bonding jumper to the actuator bonding tab 

surface bond.

 (Continued on next page)

AWL Number Task Interval Applicability Description

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

28-AWL-27,

Continued

CDCCL NA 747-400 airplanes 

Line Numbers 1382 

and on;

or airplanes that 

have incorporated 

Service Bulletin 

747-28A2292 and 

747-28A2294.

Fault Current Protection - Motor Operated Valve (MOV) ActuatII. If the MOV actuator is mounted without an adapter plate. 

1. Maintain the following If the MOV actuator is removed and 

a. Install sealed electrical fay surface bond between the m

and structure.

b. With the bonding jumper not installed, verify electrical 

actuator mounting feet and the spar is 0.005 ohms (5 m

c. Prior to attachment of the bonding jumper to the actua

resistance between the loose end of the bonding jump0.0015 ohms (1.5 milliohms) or less,

d. Attach the bonding jumper to the actuator bonding tab 

surface bond.

28-AWL-28 ALI 1 YR 747-400 airplanes 

Line Number 1394 

and on;

or airplanes that 

have incorporated 

Service Bulletin

747-28A2261.

Main Fuel Tank Boost Fuel Pump Ground Fault Interruption (G

Concern: GFI is installed to protect against burn-through of the against overheating of the pump cavity and/or auto ignition temof the housing, due to electrical arcing.Perform an Operational Test of all Main Fuel Tank Boost Pump

accordance with Boeing AMM 28-22-00.

28-AWL-29 ALI 1 YR 747-400 airplanes 

with Electric Center 

Wing Tank Scavenge 

Systems, airplanes 

prior to Line Number 

972 that have 

incorporated 

Service Bulletin 

747-28A2261.

Center Wing Tank Electrical Scavenge Pump Ground Fault InteSystemConcern: GFI is installed to protect against burn-through of the against overheating of the pump cavity and/or auto ignition temof the housing, due to electrical arcing.Perform an Operational Test of all center wing tank scavenge s

accordance with Boeing AMM 28-22-00.

AWL Number Task Interval Applicability Description

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

28-AWL-30 CDCCL NA 747-400 (910K)

with Auxiliary

Fuel Tank

Electronic Fuel Level Indication System (EFLI) – Out Of Tank WRequirementConcern: Potential for hot shorts and EMI induced voltages on tank to enter the fuel tank.Routing and installation of any new wiring must use wire types BMS 13-58, and not be within a 2-inch radius of the EFLI wirinseparation greater than 1⁄2 inch must be maintained from AUX 

28-AWL-31 CDCCL NA 747-400 (910K)

with Auxiliary

Fuel Tank

Electronic Fuel Level Indication System (EFLI) Processor DispEFLI – RepairConcern: Potential for maintenance error during PDU repair. Tdesigned to limit the levels of energy, voltage, current, and powcircuit to intrinsically safe levels in order to preclude the potentfuel tank.Repair and overhaul of PDU must be in accordance with ParkeRevision 0, or later revisions of this CMM that have been approOffice.

28-AWL-32 CDCCL NA 747-400 (910K)

with Auxiliary

Fuel Tank

Fuel Tank Electronic Fuel Level Indication System (EFLI) – ReConcern: Potential for maintenance error during repair of in-tandevelop that could result in an ignition source inside the fuel taEFLI probe repair and overhaul must be in accordance with PaRevision 1, or later revisions that have been approved by the F

28-AWL-33 ALI 12 YR All airplanes that 

have incorporated 

Service Bulletins 

747-57A2327 

and 747-28A2324

Teflon Sleeving – Out-of-Tank Wire BundleConcern: Potential for hot short induced voltages on out-of-tanfuel tank due to chafing.Perform a visual (detailed) inspection and verify the following to bundle Teflon sleeving:1. Teflon sleeving are installed around wire bundle in clamp lo

Bulletins 747-57A2327 and 747-28A2324.

2. Teflon sleeves are not damaged.3. Clamps are not missing or damaged.

AWL Number Task Interval Applicability Description

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

28-AWL-34 CDCCL N/A All airplanes that 

have incorporated 

Service Bulletins 

747-57A2327 

and 747-28A2324

Teflon Sleeving – Out-of-Tank Wire BundleConcern: Potential for hot short induced voltages on out-of-tanfuel tank due to chafing.The following design features must be verified when the out-ofremoved or replaced, in order to ensure the integrity of the wire 1. The Teflon sleeving is installed around the wiring in the clam

Service Bulletins 747-57A2327 and 747-28A2324.

2. Sleeving is not damaged.

28-AWL-35 CDCCL N/A All airplanes that 

have incorporated 

Service Bulletin 

747-28A2306

Fuel Boost Pump Wires In Conduit Installation – In Fuel TankConcern: Potential for the boost pump wiring to chafe and arc tignition source in the fuel tank. The boost pump wires that are 

have incorporated a conduit liner and a Teflon sleeve to protecalso has a shield (grounded at both ends) that is monitored by tprotection for a pump power wire short within the conduit.The following design features must be verified when the pump conduit is removed or replaced (refer to Boeing AMM 28-22-061. Jacketed and shielded (grounded at both ends) wiring is ins2. A Teflon sleeve is installed.3. A Conduit Liner is installed.NOTE: The above requirement applies to the following Fuel BoMain Tank No.1 FWD Fuel Boost PumpMain Tank No. 1 AFT Fuel Boost PumpMain Tank No. 4 FWD Fuel Boost PumpMain Tank No. 4 AFT Fuel Boost Pump.

AWL Number Task Interval Applicability Description

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

28-AWL-36 CDCCL N/A All airplanes that 

have incorporated 

Service Bulletin 

747-28A2204 but 

have not 

incorporated 

Service Bulletin 

747-28A2306

Fuel Boost Pump Wires in Conduit Installation – In Fuel TankConcern: Potential for the boost pump wiring to chafe and arc tignition source in the fuel tank.The following design features must be verified when the pump removed or replaced (refer to Boeing AMM 28-22-06):1. A Wiring Jacket and Teflon sleeve, Part Number TFE 2X, aNOTE: The Teflon sleeve is not repairable.NOTE: The above requirement applies to the following Fuel BoMain Tank No.1 FWD Fuel Boost PumpMain Tank No. 1 AFT Fuel Boost PumpMain Tank No. 4 FWD Fuel Boost PumpMain Tank No. 4 AFT Fuel Boost Pump

28-AWL-37 CDCCL N/A ALL Lightning, Fault Current or Hot Short Protection Features – In T

Concern: Potential for arcing or sparking inside the tank at a costructure interface as a result of electrical fault currents or lightinsufficient bonding within the ground electrical path. Sealant dadhesion could affect the fuel tank ignition prevention features

If any maintenance, preventive maintenance, or alteration is peverify the following in the affected areas (including the touchpo

the tank access point) where work is performed (refer to Boein1. Fillet seals around the periphery of the equipment interface 

are not damaged such as peeling off or cracking. 

2. Cap seals installed on fasteners and fittings inside the tank 

peeling off or cracking. NOTE: Not all fasteners and fittings have cap seals. If fastdamaged, there will be residual evidence of a previously insfittings in areas where installation is required. In addition, aalterations require cap seals in accordance with AWL 28-AW

AWL Number Task Interval Applicability Description

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

B.2 IMPACT-RESISTANT FUEL TANK ACCESS DOORS

INTRODUCTIONThe 747 Fuel Tank Access Doors are compliant with FAA Title 14 CFR § 25.963. Specifically, the 747 Impact-Resistant Access 

§ 25.963(e)(1) which requires that all covers located in an area where experience or analysis indicates a strike is likely must be to minimize penetration and deformation by tire fragments, low energy engine debris, or other likely debris. All 747-400 airplane

impact-resistant access doors except for two locations retrofitted by Service Bulletin 747-28-2236. The following stencil, “IMPA

also required on each door. Additionally, the adjacent lower wing surface is stenciled “CAUTION: INSTALL ONLY IMPACT-RE

LOCATION”.Boeing chose to use a CDCCL for the AWL of the Impact-Resistant Fuel Tank Access Doors. CDCCLs are commonly used an

to define a design feature that must be maintained throughout the life of the airplane.

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

57-AWL-01 CDCCL N/A ALL Impact-Resistant Fuel Tank Access Doors

Concern: A potential exists for non-impact-resistant doors to brequire impact-resistant doors. A high energy impact on a non

Access Door may cause a fuel leak, and in the presence of an catastrophic fire.Immediately prior to the installation of each of the Fuel Tank A

545AB, 645AB, 545BB, 645BB, 546AB, 646AB, 546BB, 646B652BB, 552CB, 652CB, 552DB, 652DB, 552EB, 652EB, perfo1. Verify that the Fuel Tank Access Door is impact-resistant. I

smooth inner surface. Doors with visible machined stiffening not impact-resistant (refer to Boeing AMM 28-11-02).

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

B.3 NITROGEN GENERATION SYSTEM (NGS)

The following list of AWLs (ALIs and CDCCLs) contains FAA approved scheduled inspections for operators to incorporate into 

for this type design to meet the requirements for the introduction of the Flammability Rule Reduction Means (FRM) Nitrogen Ge

The FAA operational rule change E8-16084 Final Flammability Rule requires maintenance instructions and control limitations fo

design configurations. Title 14 CFR § 25.981 (d) also requires AWLs to preclude ignition sources inside the fuel tank that may 

addition of NGS.E8-16084, Final Flammability Rule, Paragraph III(F), Section 7, Identification of Airworthiness Limitations: Paragraph M25.4(a) 

used to comply with Paragraph M25.1, AWLs must be identified for all maintenance or inspection tasks required to identify failuthe FRM that are needed to meet Paragraph M25.1. NGS AWLs are mandatory maintenance actions that ensure that unsafe c

NGS failures do not occur or are not introduced into the airplane as a result of configuration changes, repairs, alterations, or de

maintenance program throughout the operational life of the airplane.

JUN 2014
D621U400-9

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747-400 MAINTENANCE PLANNING DATA

AWLs – NITROGEN GENERATION SYSTEM

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

47-AWL-01 CDCCL N/A 747-400 airplane

Line Numbers 1363 

through 1419 or 

747-400 Line 

Numbers 1362 and 

prior that have 

incorporated all or part 

of Service Bulletin

747-47-2006

Lightning Protection – NGS NEA Description Line Fuel Tank Concern: Potential for arcing, sparking of filament heating in

between the bulkhead fitting and the spar during a lightning 

The following must be maintained if the bulkhead fitting or at

replaced, or reinstalled (refer to Boeing AMM 47-21-06):

1. Install the same part number bulkhead fitting.

2. Verify electrical fay surface bond between the bulkhead fit

structure inside the tank is 0.0005 ohms (0.5 milliohms) o

3. Install full-bodied fillet seal encapsulating the bulkhead fitt

inside and outside surfaces of the front spar, and the first cto the bulkhead fitting inside the tank,

4. Install full-bodied fillet seal encapsulating the first coupling 

and

5. Verify electrical bond from structure to first tube mating w

0.010 ohms or less.

Note: The bulkhead fitting is a special part which has an inte

changes to this part require approval by the FAA Oversight O

JUN 2014
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

47-AWL-02 CDCCL N/A 747-400 airplanes 

that have 

incorporated

 Service Bulletin 

747-47-2006

Nitrogen Generation System (NGS) – Flammability Exposure 

Concern: Airplane alterations may impact the performance of flammability of the Center Wing Fuel Tank.Background: The NGS is designed to provide the proper levewing tank in order to reduce the flammability exposure by reduthe ullage. The flammability exposure is also affected by the te

following are critical features of the airplane that, if altered, ca

performance of the NGS which in turn may increase the cente

exposure beyond the limits of Title 14 CFR § 25.981 at Amenequivalent level of safety finding described in FAA Memorand1. Transferring air (20.9% oxygen) to the center fuel tank will 

atmosphere created by the NGS in the fuel tank. Some Autransfer air to the center wing tank as part of venting and fu

2. NGS performance depends on bleed air pressure in the bl

supplied by the engines.

3. Certification of the NGS depends on the inherent flammab

without NGS installed. Center tank flammability is a direct temperature. Any heat sources around the tank, heat sou(such as warm fuel or new heat exchangers), or changes tretained (such installation of blankets adjacent to tank wal

flammability in a negative manner.

CDCCL: Any design change that affects the vent system by areduces the bleed pressure in the cross-over manifold during ground operations, or adds any heat to the center wing fuel taretention of the center wing fuel tank is not allowed without an show that the change, or combination of changes, does not a

per the requirements of Title 14 CFR § 25.981(b), Amendmenequivalent level of safety finding described in FAA MemorandSee Boeing AMM Chapter 28 for a description of the Fuel SysChapter 47 for a description of the NGS.

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

47-AWL-03

DELETED

ALI 1200 Flight 

Hours

747-400 airplane

Line Numbers 1363, 

1366

Nitrogen Generation System – Functional Check PerformancConcern: Latent failure of the Hollow Fiber Membranes that 

Modules (ASMs) will reduce the percentage of nitrogen in th

the center wing fuel tank.

Perform the inspection procedure listed in Boeing AMM 47-0

1. Measure the oxygen concentration of the NEA at the outp

AMM 47-00-01.

2. Verify the NEA purity is in the satisfactory zone (shaded a

performance charts published in Boeing AMM 47-00-01.

If the nitrogen content is not satisfactory, troubleshoot per Bo

perform the recommended repairs per Boeing AMM 47-00-0

47-AWL-04

DELETED

ALI 9675 Flight 

Hours

747-400 airplane

Line Numbers 1363, 

1366

Nitrogen Generation System – Thermal Switch Functional anConcern: Latent failure of the Thermal Switch removes a lay

ignition by hot bleed air.

The NGS uses engine bleed air from the bleed system cross

nitrogen to reduce the flammability of the center fuel tank. Thdirectly feeding hot bleed air into the fuel tank. The Thermal backup to the NGS controller to protect the ASMs and prevenfuel tank. The Thermal Switch backup feature is a latent (not tested to maintain certification of the NGS. 

Perform a functional and operational test of the thermal switc

ensure the integrity of the thermal switch.

47-AWL-05

DELETED

ALI 1500 Cycles 

or 7500 

Flight Hours

Note

747-400 airplane

Line Numbers 1363, 

1366

Nitrogen Generation System – Thermal Control Unit (TCU) a

Replacement/UpgradeConcern: The TCU pallet failed vibration testing during qualivibration analysis demonstrates limited life capability. The TC

fail in service if not replaced or upgraded.Replace the TCU Assembly P/N 5848740-1 or Duct Assembof TCU)

Replace the interconnect duct P/N 5849599-1.Interval Note: Whichever comes first.

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

OCT 2011
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

47-AWL-06

DELETED

ALI 3000 Cycles 

or 15000 

Flight Hours

Note

747-400 airplane

Line Numbers 1363, 

1366

Nitrogen Generation System – Air Separation Unit (ASU) Replacem

Concern: The ASU pallet failed vibration testing during qualificationreplaced or upgraded.Replace ASU Assembly P/N 5848760-1 or the following combinatio

- Overtemperature Shutoff Valve Bracket P/N 5849542-41

- Nitrogen Enriched Air Bracket P/N 5849542-25- Two ASM Inlet Ducts P/N 5849548-1 (one on the primary ASM an secondary ASM)- Supply Air Primary Duct Assembly P/N 5849557-1.

Interval Note: Whichever comes first.

47-AWL-07 ALI 21,250 Flight 

Hours

747-400 airplanes that 

have incorporated

 Service Bulletin

747-47-2006

Nitrogen Generation System – Nitrogen Enriched Air (NEA) DistribuConcern: The NEA Distribution System ducting outside the fuel tan

leak without reaching the fuel tank, resulting in the fuel tank not rea

Inspect the NEA distribution lines from the ASM to the fuel tank fron

47-AWL-08 ALI 21,250 Flight 

Hours

747-400 airplanes that 

have incorporated

Service Bulletin

747-47-2006

Nitrogen Generation System – Cross-Vent Check Valve – FunctionConcern: The Cross-Vent Check Valve may fail open latently allow

tank diluting the nitrogen rich environment created by the Nitrogen 

Functionally check the Cross-Vent Check Valve by accessing the C

inspect the Cross-Vent Check Valve.

47-AWL-09 CDCCL N/A 747-400 airplanes that 

have incorporated 

Service Bulletin

747-47-2006

Industry Fleet Average Flammability ExposureConcern: NGS performance is dependent on industry descent times

time may result in NGS performance that does not meet FAA requi

Fleet Average flammability exposure for the fuel tanks with flamma

must be maintained in accordance with Title 14 CFR Part 25, Appedescent statistics and, if necessary to maintain compliance, will pubpublishes such service information, this CDCCL requires that operaapproved design changes or that operators implement other design changes approved by the FAA Oversight Office to maintain compliaAppendix M.

NOTE: This CDCCL does not require individual operators to monito

Boeing will monitor U.S. descent statistics and provide any needed To prevent increasing flammability exposure above permissible leveto incorporate future Boeing published service instructions denoted CDCCL, or other approved actions, within the compliance times sta

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

JUN 2014
D621U400-9

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

747-400 MAINTENANCE PLANNING DATA

NOTE: SHADED AWLs HAVE BEEN DELETED.

47-AWL-10 ALI 54,000 FH 747-400 airplanes that 

have incorporated

Service Bulletin 

747-47-2006

NGS – Thermal Switch Functional CheckConcern: Latent failure of the Thermal Switch removes a layer of pr

hot bleed air.

The NGS uses engine bleed air from the bleed system cross-over m

reduce the flammability of the center fuel tank. The NGS has featubleed air into the fuel tank. The Thermal Switch provides a redundaprotect the Air Separation Modules (ASMs) and prevent hot bleed a

Thermal Switch backup feature is a latent (not detected) failure.

Remove and replace the NGS Thermal Switch with a new unit. 

(Refer to Boeing AMM 47-42-04 for removal and installation).

AWL

NUMBER TASK INTERVAL APPLICABILITY DESCRIPTION

OCT 2011
747-400 MAINTENANCE PLANNING DATA

D621U400-9

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

C. AWLs – STRUCTURAL INSPECTIONS

The 747-400 passenger airplane can be operated in a 747-400 Special Freighter (SF) configuration if modified in accordance w

bulletins. These service bulletins are identified (with associated effectivity) in Boeing Service Bulletin 747-00-2004. Airplanes c

of Boeing service bulletin(s) to the 747-400 SF configuration require existing supplemental structural inspections identified for tsupplemental structural inspections specific to the 747-400SF configuration. For the 747-400SF configuration, all of these suppshown in the 747 Supplemental Structural Inspection Document D6-35022, beginning with Revision G (and on) of that docume

After reaching the threshold specified in the 747 Supplemental Structural Inspection Document, D6-35022, 747-400SF 

above must limit all repeat intervals in MPD Section 2, Structural Maintenance Program, to the values shown therein.Airplanes converted to a 747-400 Large Cargo Freighter (LCF) configuration by incorporation of Boeing Service Bulletins 747-0

747-00-0033, or 747-00-2120 require additional supplemental structural inspections specific to the 747-400 LCF configuration. 

inspections are shown in the 747-400 LCF Supplemental Structural Inspection Document – Appendix A, D6-35022-1, dated Jaapproved revision. For these supplemental fatigue related inspections, after the airplane reaches the threshold specified in D6-

January 2010, or later FAA approved revision, the repeat intervals of the C-Checks and D-Checks specified by the MPD must baddition to the required limitation for flight hours and calendar time. For MRBR Section 3, Structural Maintenance Program, an

Maintenance Program, the check intervals must not exceed the following:C-Check – 1,500 flight cycles2C-Check – 3,000 flight cyclesD-Check – 6,000 flight cycles2D-Check – 12,000 flight cyclesAircraft converted to the 747-400 LCF configuration also require the revised inspection and modification requirements listed in 747-53A2817 Rev. 00, or a later revision approved by the Manager of the FAA Oversight Office, in order to adequately address 

structure and internal loads/stresses. When Boeing Service Bulletin 747-53A2817 states to contact the Boeing Company for mo

modification data must be approved by the manager of the FAA Oversight Office.

JUN 2014
D621U400-9

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747-400 MAINTENANCE PLANNING DATA

C.1 LIMIT OF VALIDITY (LOV)

This section provides the Limit of Validity (LOV) in accordance with the requirements of Title 14 CFR § 26.21 (Amendment 26-6

the establishment of an airplane level limit of validity of the engineering data that supports the structural maintenance program period of time, stated as a number of total accumulated flight cycles or flight hours or both, during which it is demonstrated that will not occur in the airplane. The LOVs listed in the following table support operator compliance with Title 14 CFR § 121.1115 

747-400s.

LIMIT OF VALIDITY FOR THE 747-400

MODEL FLIGHT CYCLE LOV FLIGHT HOUR LOV

747-400, 747-400D, 747-400F, 

747-400SF(BCF), 747-400LCF 35,000 165,000

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747-400 MAINTENANCE PLANNING DATA

D621U400-9

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D. CERTIFICATION MAINTENANCE REQUIREMENTS (CMRs)

SELECTION OF CMRsIn order to grant operators of the 747-400 airplane an opportunity to participate in the evaluation and selection of CMRs in an in

tasks and intervals, a Certification Maintenance Coordination Committee (CMCC) was convened to review all of the 747-400 Cthis document are the result of applying the CMCC process as described in AC 25-19.CMR DEFINITIONAs defined by AC 25-19, a CMR is a required periodic task, established during the design certification of the airplane as an opecertificate. CMRs usually result from a formal, numerical analysis conducted to show compliance with catastrophic and hazardAdditional notes concerning the definition of CMRs:1. A CMR is intended to detect safety-significant latent (hidden) failures that would, in combination with one or more specific f

hazardous or catastrophic failure condition.

2. It is important to note that CMRs are derived from a fundamentally different analysis process than the maintenance tasks a

the Maintenance Steering Group (MSG-3) Analysis associated with Maintenance Review Board (MRB) activities. MSG-3 A

maintenance tasks that are performed for safety, operational, or economic reasons, involving both preventative maintenance before failure occurs (and are intended to prevent failures), as well as failure-finding tasks. CMRs, on the other hand, are faexist solely to limit the exposure to otherwise hidden failures. Although CMR Tasks are failure-finding tasks, use of potentiaas functional checks and inspections, may also be appropriate.

3. CMRs are designed to verify that a certain failure has or has not occurred, and do not provide any preventative maintenanc

the failure clock to zero” for latent failures by verifying that the item has not failed, or cause repair if it has failed. Because t

failure is a key element in the calculations used in a safety analysis performed to show compliance with Title 14 CFR § 25.time will have a significant effect on the resultant overall failure probability of the system. The CMR task interval should be 

hours, cycles, or calendar time, as appropriate.

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4. The type certification process assumes that the airplane will be maintained in a condition of airworthiness at least equal to its 

condition. The process described in AC 25-19 is not intended to establish normal maintenance tasks that should be define

analysis process. Also, this process is not intended to establish CMRs for the purpose of providing supplemental margins olate in the type design approval process.

5. CMRs should not be confused with required structural inspection programs that are developed by the type certificate applic

requirements for damage tolerance, as required by Title 14 CFR § 25.571 or § 25.1529, Appendix H25.4 (Airworthiness Limto be developed and administered separately from any structural inspection programs.

EXCEPTIONAL SHORT-TERM EXTENSIONS FOR CMRsSince CMR intervals are based on statistical averages and reliability rates, an exceptional short-term extension of 90 days for C

in this document may be made without jeopardizing safety. The local regulatory authority or a Principle Maintenance Inspector 

exceptional short-term extensions before they take place using procedures established with the local regulatory authority in the “exceptional short-term extension” process is applicable to CMR intervals. It should not be confused with the operator’s “short-for normal maintenance tasks described in the operators’ manuals and in the Flight Standards Handbook 8900.1 FSIMS.The FAA Oversight Office has accepted that these exceptional short-term extensions may be granted without consultation with 1. The term “exceptional short-term extension” is defined as an increase in a CMR interval that may be needed to cover an un

situation. CMRs 24, 25, and 26 listed in this document have been approved with an exceptional short-term extension of 90 

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

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

3. After a CMR has experienced an exceptional short-term extension, the CMR interval will revert back to its interval listed in t

Oversight Office must approve, prior to its use, any desired extension not explicitly listed above.

NOTE: This exceptional short-term extension listed above applies to airlines that fall under the United States FAA jurisdiction 

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

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POST-CERTIFICATION CHANGES TO CMRSAny post certification changes to CMRs should be reviewed by the 747-400 CMCC and approved by the FAA Oversight Office:1. Since the purpose of a CMR is to limit the exposure time to a given significant latent failure as part of an engineering analysis 

instances of a CMR task repeatedly finding that no failure has occurred may not be sufficient justification for deleting the ta

2. The introduction of a new CMR should be reviewed by the same process used during initial certification. It is important tha

same opportunity to participate that they received during the original certification of the airplane, in order to allow the operamaintenance programs.

3. In the event that later data provide sufficient basis for relaxation of a CMR (less restrictive actions to be required), the change 

FAA Oversight Office approved change to this CMR document.

4. If the requirements of an existing CMR must be decreased (more restrictive actions to be performed), it will be implemented 

document and enforced by an FAA Airworthiness Directive (AD).

5. After initial aircraft certification, the only basis for adding a new CMR is in association with the certification of design change

6. A new CMR created as part of a design change should be part of the approved data for that change and added to this CMR In the event that a CMR is revised, Boeing will document it by preparing a revision to this document that will be approved by the 

This revision will then be forwarded to all 747-400 operators and the FAA Oversight Office.

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747-400 MAINTENANCE PLANNING DATA

CMR TASKS

NUMBER SYSTEM INTERVAL TASK

1 Standby Power System Daily Operational (Short) Test – 115-Volt AC Standby 

Power Generation

M

DSPa

2 Cargo, Engine and APU Fire/Overheat 

Detection System. (Only applicable to Engine Fire/Overheat Detection System for 747-400 LCF)

Daily Operational Test for Fire/Overheat Detection 

Systems

M

DSPa

3 FADEC C2 Failures 2000 FH 

(GE CF6-

80C2B1F)

1000 FH

(PW4000)

560 FH

(RR RB211-524)

Check Engine Control System for Category 2 

Faults using the CMC

M

DSPa

4 Generator Control Unit and Bus Control Unit 500 FH Operational Test - Generator and Bus Control Units M

DSPa

5 Lavatory Waste Compartment 1000 FH Lavatory Waste Compartment Inspection Check M

DSPa

AUG 2012
747-400 MAINTENANCE PLANNING DATA

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6 E&E Cooling System Override Mode 

Function

1000 FH

(Not Applicable 

to 747-400F or 

747-400SF)

20,000 FH

(Applicable to 

747-400F and 

747-400SF)

Override Mode – Operational Test M

DSPa

7 High Lift Control System

A. Trailing Edge Electric ControlB. Leading Edge Electric Control

1200 FH1200 FH

Primary Electric Operational Test of LE and TE 

Flap Systems.

M

DSPa

8 High Lift Control System

A. Alternate Arm SwitchB. Alternate Control

1200 FH

10,000 FH

Alternate Electrical Operational Test of LE and 

TE Flap System.

M

DSPa

9 E&E Cooling System Flow Detectors 

(Not Applicable to 747-400F or 747-400SF)

2000 FH Remove Clean and Install Low Flow Detectors. M

DSPa

10 E&E Cooling System Smoke & Flow 

Detection (Not Applicable to 747-400F or 747-400SF)

2000 FH Equipment Cooling Detector Ground Test M

DSPa

11 E&E Cooling System E30-2 Shelf 2000 FH System Test-E30 Rack Pressure 

(Equipment Cooling System)

M

DSPa

12 E&E Cooling System Fans & Bypass Valve 

(Not applicable to 747-400F or 747-400SF)

2000 FH Fan and Bypass Valve Operational Test 

(Normal Mode)

M

DSPa

NUMBER SYSTEM INTERVAL TASK

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13 E&E Cooling System Fan Check Valves 

(Not Applicable to 747-400F or 747-400SF)

6250 FH Check Valve – Detail Visual Inspection M

DSPa

14 E&E Cooling System Clean Mode 

(Not Applicable to 747-400F or 747-400SF)

6250 FH Clean Cycle – Operational Test (Equipment 

Cooling Card CMC initiated BIT)

M

DSPa

15 E6/E9 Equipment Cooling Valve 

(Not applicable to 747-400F, 747-400SF or 747-400 LCF)

6250 FH Cargo Fire Switch Test M

DSPa

16 Horizontal Stabilizer Fuel Tank Installation 

(Only applicable to 747-400’s equipped with horizontal stabilizer fuel capability.) (Not applicable to 747-400 LCF)

6250 FH Inspection of Horizontal Stabilizer Bonding 

Jumpers (Applicable only to airplanes with horizontal stabilizer fuel quantity gage and controls on Fuel Control Panel)

M

DSPa

17 Upper Rudder System 6250 FH Test Upper Rudder Hinge Bearing and Rudder 

Power Control Package Bearing Play

M

DSPa

NUMBER SYSTEM INTERVAL TASK

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18 Main Entry Door Escape System (Not 

Applicable to 747-400F, 747-400SF or Door #5 on Combi Airplanes in Cargo Mode. See Note (1).(Only applicable to Door #1 L/H for 747-400 LCF)

30 months/

36 months -

 See Note (2)

Main Entry Door Escape System Functional CheckNote (1): On Combi airplanes, the check is also 

required on Door #5 immediately after conversion to passenger mode

Note (2): The reference functional check 

procedure covering examination of the escape slide or slide/raft packs, may be accomplished at 30 month intervals, (the remainder of the procedure at 36 month intervals)

Se

SMDSPaPaEInMDSPaEInExsl

19 Engine Strut Spring Beam 12500 FH Spring Beam Bearing Movement Check M

DSPa

20 Lower Lobe Cargo Compartment 

Conditioned Air System (Non-Standard, if installed)(Not Applicable to 747-400F, 747-400SF or 747-400 LCF)

7400 FH Check for Air Conditioning Pack Number 3 Flow 

Control Valve High Flow Disable with Lower Lobe Cargo Compartment Conditioned Air On

M

DSPa

21 Engine Position 2 Turbine Overspeed 

System (RR RB211-524 series engines)Note: For RB 211 powered 747-400’s equipped with EICAS version RR004, CMR No. 21 is not applicable.DELETED

150 FH Interrogate CMC fault history (ATA 73) and look for 

CMCS message 72663 Turbine Overspeed Disabled. If found, do fault isolation per 71 CMCS message index.

M

DSPa

NUMBER SYSTEM INTERVAL TASK

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22 Engine Oil Servicing (P&W 4000)

DELETED

Every 12 quarts 

added

Drain residual oil from gearbox. M

DSPa

23 Combi Main Deck Fire Protection System 

Zones D and E Air Distribution Shutoff Valves, V532 and V533. (Not applicable to 747-400 LCF)

6250 FH Main Deck Air Distribution Flapper Valve 

Adjustment/Test.

M

DSPa

24 Flight Deck Security Doors Installed per 

Service Bulletin 747-25-3302 (Not applicable to 747-400 LCF)

9 Years Discard the Adams Rite strike mechanism. M

DSPa

25 Flight Deck Security Doors Installed per 

Service Bulletin 747-25-3306 and/or 747-25-3312.(Not applicable to 747-400 LCF)

9 Years Discard the Adams Rite strike mechanism. M

DSPa

26 Flight Deck Security Doors Installed 

beginning at the line number 1320 and on (except freighter models).(Not applicable to 747-400 LCF)

9 Years Discard the Adams Rite strike mechanism. M

DSPa

27 Fuel main tanks 1 & 4 and fuel reserve tanks 

2 & 3 VTO secondary shut-off system (Applicable to 747-400 LCF only) 

15000 FH Functional Check of the fuel main tanks 1 & 4 and 

fuel reserve tanks 2 & 3 VTO secondary shut-off system.

M

DSPa

NOTE: SHADED CMRs HAVE BEEN DELETED.

NUMBER SYSTEM INTERVAL TASK

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E. REPORTING UNCONTROLLABLE HIGH THRUST FAILURE CONDITIONS

Title 14 CFR § 121.703 and § 135.415 state that “each certificate holder shall report any failure, malfunction, or defect in an air

or powerplant that occurs or is detected at any time if, in its opinion, that failure, malfunction, or defect has endangered or may 

operation of an aircraft”. Title 14 CFR § 125.409 also requires reporting of failures, malfunctions or defects. In many cases a re

malfunction will be obvious, but there are some failure modes related to uncontrolled high thrust that are reportable but may no

information is provided, as required by FAA Exemption No. 8518, to assist the operators in identifying reportable malfunctions r

high thrust.The FAA has concluded that the loss of capability to control thrust due to a failure of the engine thrust control system may endaincludes any malfunctions having one or more of the following characteristics:• Auto-acceleration or uncommanded thrust change to higher power• Stuck thrust lever above idle power• Inability to reduce thrustAlthough some of these incidents may not appear to be safety related, documenting the events is important to ensure the presemaintained and/or to identify failure conditions that must be corrected.

When filing a report of such an event with the FAA, the operator is requested to include in the description of the event one or m

phrases:• “thrust control”• “no response to thrust lever”• “auto-acceleration”• “uncontrolled high thrust”

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In addition, the following information should be included in the report:• Event description• Flight Crew action• Maintenance action• List of affected or removed componentsReports should be submitted to the local representative of the FAA Administrator that handles the appropriate reporting respon§ 121.703, § 125.409, and § 135.415. In addition to filing reports with the FAA, it is recommended that a copy be sent to Boein

manufacturer.

JUN 2014