747-8/8F CERTIFICATION MAINTENANCE REQUIREMENTS

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747-8/8F

CERTIFICATION MAINTENANCE REQUIREMENTS (CM

D011U721-02-03

DECEMBER 2013

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COMPILED AND PUBLISHED BY:

MAINTENANCE PROGRAMS ENGINEERING

COMMERCIAL AVIATION SERVICES

BOEING COMMERCIAL AIRPLANE GROUP

SEATTLE, WASHINGTON

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TABLE OF CONTENTS

REVISIONS .......................................................................................................................................................................................LIST OF EFFECTIVE PAGES ...........................................................................................................................................................A. SCOPE..........................................................................................................................................................................................B. EXCEPTIONAL SHORT-TERM EXTENSIONS ............................................................................................................................C. POST-CERTIFICATION CHANGES .............................................................................................................................................D. CERTIFICATION MAINTENANCE REQUIREMENTS..................................................................................................................E. CERTIFICATION MAINTENANCE REQUIREMENTS REQUIRED BY AIRWORTHINESS DIRECTIVES ..................................F. CERTIFICATION MAINTENANCE REQUIREMENTS REQUIRED BY OTHER SAFETY ANALYSIS USED FOR CERTIFCATIO

G. CMR TASKS..................................................................................................................................................................................APPENDIX A. SYSTEMS COMPONENTS LIFE-LIMITED ITEMS ...................................................................................................

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REVISIONS

REVISION AND REVISION DESCRIPTION APPROVAL

AUGUST 2011Original Release.

Submitted by: Kevin Perry (Boeing) Approved 

 

AUGUST 2011 R1Added a new CMR to check for outboard aileron inboard actuator failures (27-CMR-09).

Submitted by: Kevin Perry (Boeing) Approved 

  

SEPTEMBER 2011Revised the last paragraph in Section C by revising “747-8I” to “747-8” to include all 747-8 passenger model airplanes.Revised Appendix A by revising the systems life limited part applicability from “747-8I” to “747-8” to include all 747-8 passenger model airplanes.

Submitted by: Kevin Perry (Boeing) Approved 

 

DECEMBER 2011Revised airplane applicability for 27-CMR-09.

Submitted by: Kevin Perry (Boeing) Approved 

 

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747-8/8F CERTIFICATION MAINTENANCE REQUIREMENTS

MAY 2012Revised airplane applicability for 27-CMR-08 from "ALL" to "Applicable to 747-8 airplanes prior to line number 1462 and those airplanes that have not incorporated Service Bulletin 747-27-2501."

Submitted by: Paul Beuter (Boeing) Approved 

  

AUGUST 2013Added two new Certification Maintenance Requirement Tasks:27-CMR-10 – Lubricate inboard elevator hinge bearings. 27-CMR-11 – Functional check of inboard elevator hinge bearing and power control unit rod end bearing play.

Submitted by: Matthew Razniewski (Boeing)

DECEMBER 2013Revised 24-CMR-01 interval from "24 HRS" to "100 FH" and removed Interval Note in accordance with the approved 747-8/-8F Electrical Power System Safety Assessment Document.

Submitted by: Matthew Razniewski (Boeing) 

REVISIONS

REVISION AND REVISION DESCRIPTION APPROVAL

DEC 2013
Section Page Date Section Page Date Section Page Date Section Page Date 

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LIST OF EFFECTIVE PAGES

747-8/8F CERTIFICATION MAINTENANCE REQUIREMENTS

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A. SCOPE

The 747-8/8F scheduled maintenance requirements described in this document result from airplane certification activities with t

Administration (FAA), and this FAA approved Certification Maintenance Requirements (CMR) document is cross-referenced in 

Certificate Data Sheet A20WE as an Airworthiness Limitations Section of the Instructions for Continued Airworthiness. These srequirements may only be revised by the Seattle FAA Aircraft Certification Office (ACO); principal airworthiness inspectors (locanot change these requirements or the intervals associated with these requirements without FAA ACO approval.

B. EXCEPTIONAL SHORT-TERM EXTENSIONS

Intervals for these CMRs are based on statistical averages and reliability rates except for 27-CMR-06, 27-CMR-07, and Life-lim

Appendix A. An exceptional short-term extension of 10% for CMRs based on statistical averages and reliability rates may be m

safety. The local regulatory authority must concur with any exceptional short-term extensions before they take place using proclocal regulatory authority in the operators' manuals. The "exceptional short-term extension" process is applicable to CMR interv

confused with the operator's "short-term escalation" program for normal maintenance tasks described in the operators' continuomaintenance program.The Seattle FAA ACO has accepted that these exceptional short-term extensions may be granted without consultation with tha

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 based on statistical averages and reliability rates have been approved for an exceptional short-term extens

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.

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

ACO must approve, prior to its use, any desired extension not explicitly listed above.The exceptional short-term extension listed above applies to airlines that fall under the United States FAA jurisdiction only. Ope

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

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C. POST-CERTIFICATION CHANGES

Any post-certification changes to CMRs must be approved by the Seattle FAA ACO.

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 that 

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 ACO 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 for all 747-8 and 747-8F airplanes, Boeing will document it by preparing a revision to this docby the Seattle FAA ACO. This revision will then be forwarded to all 747-8/8F operators and the Seattle FAA ACO offices.

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D. CERTIFICATION MAINTENANCE REQUIREMENTS

SELECTION OF CMRsIn order to grant operators of the 747-8/8F 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 747-8/8F C

this 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 Amaintenance 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 potential f

functional checks and inspections, may also be appropriate.

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

"restart the failure clock to zero" for latent failures by verifying that the item has not failed, or cause repair if it has failed. Bec

latent failure is a key element in the calculations used in a safety analysis performed to show compliance with 14 CFR 25.1

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 defined 

process. Also, this process is not intended to establish CMRs for the purpose of providing supplemental margins of safety fo

type design approval process.

CMR TASK TYPESCMR Tasks are divided into two categories: One Star (*) CMRs and Two Star (**) CMRs. They are defined as follows:1. One Star (*) CMRs - The tasks and intervals specified are mandatory and cannot be changed, escalated, or deleted withou

Seattle FAA ACO.

2. Two Star (**) CMRs - Task intervals may be adjusted in accordance with each operator's approved escalation program or a

program in a like manner for any MRB Report task, but may not be deleted without prior Seattle FAA ACO approval.

ESCALATION OF TWO STAR (**) CMRs All Two Star (**) CMRs can be managed and controlled the same as any MRB Report task; however, they can not be deleted fr

without prior Seattle FAA ACO approval. For operators with approved escalation practices or an approved reliability program, dtechniques are used to make adjustments to an operator's maintenance program. It has been demonstrated that the managem

program does not give rise to undue escalations; consequently, the escalation of Two Star (**) CMR intervals within an operatorbe properly managed by the operator subject to local regulatory authority approval

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E. CERTIFICATION MAINTENANCE REQUIREMENTS REQUIRED BY AIRWORTHINESS DIRECTIVES

CMRs 27-CMR-06, 27-CMR-07, and Life-limited Items 2 and 3 in Appendix A are required by existing Airworthiness Directives (A

39 and do not come from system safety analysis required under 14 CFR 25.1309. CMR 27-CMR-06 is required by AD 2006-10

FAA ACO approved Alternate Method of Compliance (AMOC) for AD 2003-11-01. Life-limited Items 2 and 3 in Appendix A are 

Since CMRs 27-CMR-06, 27-CMR-07, and Life-limited Items 2 and 3 in Appendix A are required by existing ADs required under 

AMOC or a change in the compliance times for these items should be in accordance with 14 CFR 39.

F. CERTIFICATION MAINTENANCE REQUIREMENTS REQUIRED BY OTHER SAFETY ANALYSIS USED FOR CERTIFCATIO

Life-limited Item 1 in Appendix A is required by safety analysis used to certify the flight deck door. The flight deck door strike as

minimum system performance requirements in the event of a cabin decompression event (Reference FAA memorandum 01-11

revised Dec. 3, 2002).

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G. CMR TASKS

CMR

ITEM

NUMBER TYPE

RELATED 

MRB REPORT 

ITEM NUMBER CMR INTERVAL

APPLICABILITY

APL ENG TASK DESCRIPTION

21-CMR-01 * 21-058-15 12,000 FH ALL ALL Operational test of E&E cooling system override mode fu21-CMR-02 * 21-058-03

(MPD Number)

2,000 FH ALL ALL System test – E30 rack pressure at E&E cooling system 

system).

24-CMR-01 * 24-029-03

(MPD Number)

100 FH ALL ALL Operational (short) test – 115 volt AC standby power gen

24-CMR-02 * 24-023-00

(MPD Number)

500 FH ALL ALL Operational test – generator control units and bus contr

26-CMR-01 * 26-011-00 24 HRS

NOTE

ALL ALL Operational test for engine and APU fire/overheat detecti

INTERVAL NOTE: Under exceptional operational circumextended beyond 24 hours (elapsed clock hours) but noclock hours).

27-CMR-01 * 27-051-20 1,200 FH ALL ALL Operational check of the primary electrical leading and t27-CMR-02 * 27-051-10 10,000 FH ALL ALL Operational check of the alternate electrical leading and 

switch.

27-CMR-03 * 27-051-12

(MPD Number)

1,200 FH ALL ALL Operational check of the alternate electrical leading and 

switch.

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27-CMR-04 * 27-021-45 6,250 FH ALL ALL Test upper rudder hinge bearing and rudder power contr27-CMR-05 * 27-021-40 6,250 FH ALL ALL Test lower rudder tab hinge bearing and rudder control ro27-CMR-06 * 27-041-10

12-027-3427-041-05

21,000 FH

I-15,000 FH / 18 MO

R- 2,000 FH / 12 MO

I-15,000 FH / 18 MO

R- 4,000 FH / 24 MO

ALL ALL Test horizontal stabilizer trim system ballnut-to-ballscrew 

Lubricate horizontal stabilizer trim system ballnut and baInspect horizontal stabilizer trim system ballnut and ball

27-CMR-07 * 51-041-01

(MPD Number)

51-041-02

(MPD Number)

51-041-03

(MPD Number)

51-041-04

(MPD Number)

2 YR2 YR3 YR6 YR

ALL ALL Operational check of the canted pressure deck exterior d

wheel wells by purging the drain lines with compressed blockages.Inspect and restore (clean) the interior of the wing centeremoving all debris that could contaminate and obstruct inlets, water scavenge tube inlets, or water drain catch bInspect the canted pressure deck exterior surface from iwells to detect unintended water leakage paths. Inspect the canted pressure deck exterior surface from iwells with the fuselage pressurized to detect air leakage 

27-CMR-08 * 27-011-05

(MPD Number)

11,000 FH NOTE ALL Functional check of the inboard aileron power control un

AIRPLANE NOTE: Applicable to 747-8 airplanes prior to airplanes that have not incorporated Service Bulletin 74

CMR

ITEM

NUMBER TYPE

RELATED 

MRB REPORT 

ITEM NUMBER CMR INTERVAL

APPLICABILITY

APL ENG TASK DESCRIPTION

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27-CMR-09 * 27-011-07

(MPD Number)

24 HRS

NOTE

NOTE ALL Visually check the Flight Controls Maintenance Page on 

adjacent to the outboard aileron inboard actuator positioisolation procedure for the "L/R AIL ACTUATOR" status INTERVAL NOTE: Under exceptional operational circumextended beyond 24 hours (elapsed clock hours) but nohours).AIRPLANE NOTE: 747-8F airplanes prior to line numbeService Bulletin 747-31-2455 R00.

27-CMR-10 * 12-027-33

(MPD Number)

5,000 FH / 18 MO

NOTE

ALL ALL Lubricate inboard elevator hinge bearings.

INTERVAL NOTE: Whichever occurs first.

27-CMR-11 * 27-031-10

(MPD Number)

6,250 FH / 18 MO

NOTE

ALL ALL Functional check of inboard elevator hinge bearing and 

free play.INTERVAL NOTE: Whichever occurs first.

29-CMR-01 * 29-021-00 11,000 FH / 30 MO ALL ALL Functional check of the ram air turbine system, including 

the ram air turbine hydraulic system.

CMR

ITEM

NUMBER TYPE

RELATED 

MRB REPORT 

ITEM NUMBER CMR INTERVAL

APPLICABILITY

APL ENG TASK DESCRIPTION

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APPENDIX A. SYSTEMS COMPONENTS LIFE-LIMITED ITEMS

The replacement times established for life-limited parts in this appendix result from Model 747-8/8F airplane certification activitiepart of the Airworthiness Limitations Section of the Instructions for Continued Airworthiness. These maintenance actions are m

may only be revised with the approval of the Seattle FAA ACO. 

ITEM

NUMBER LIFE-LIMITED ITEM

PART 

NUMBER PART DESCRIPTION

APPLICABILITY 

SPECIFICATIONS LIF

1 Double Roller E Strike AR4704-6 Flight Deck Door Strike Assembly Applicable to 747-8 

Flight Deck Security Door

9 

2 Switch 284U7410-1 Fwd and Aft Cargo Door Control Switch Applicable to 747-8 and 

747-8F in the following 

installation positions:

Aft Cargo Door

Forward Cargo Door

6 

3 Switch 284U7410-1 Nose Cargo Door Control Switch Applicable to 747-8F in the 

following installation 

positions:

Nose Cargo Door

6 

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