development of certification maintenance requirements

8/10/2019 Development of Certification Maintenance Requirements

1/43

Development of Certification Maintenance Requirementsand Instructions for Continuing Airworthiness

Melbourne May 2013

Design and Manufacturing

Seminar


2/43

Development of Instructions for Continuing Airworthiness

A process for ICA creation performed by the OEMs as a part of Type

Certification (FAR / CS 23/25/27/29 1529, MSG 1/2/3).

Regulatory and engineering principles used for creation of

Certification Maintenance Requirements.

A process used for unique MEL items and Permissible

Unserviceability assessment and approval.

MSG 3 approach.

A process used for in house versus OEM maintenance data creation

and approval. Processes involved in TBO and maintenance task / schedule

frequency escalations and one-off escalations / overruns.


3/43


Instructions for Continuing Airworthiness (ICA) are developed

during the Type Certification process of an aircraft in accordance

with relevant certification standards. ICA are usually provided

through MM, SRM, SBs, SLs, MPD, AFM, MEL, etc.

Instructions for Continuing Airworthiness (ICA) are also

developed during the Supplemental Type Certification process

in accordance with relevant certification standards. In this case

ICA are usually provided through Supplements to MM, SRM,MPD, AFM, MEL, etc. STC Holders could also publish SBs, SLs

related to their STCs.


4/43


ICA are developed in accordance with relevant certification

standards. CASA accepts EASA CSs and FAA FARs as

acceptable relevant standards for Normal and Transport

Category Aircraft / Rotorcraft (ref. CASR Part 23/25/27/29)

ICA are developed in accordance with relevant regulations

provided in the FAR / CS 23/25/27/29 section 1529 and

applicable appendices. Section 1529 and applicable appendicesset the basic requirements for ICA.


5/43


FAR PART 25AIRWORTHINESS STANDARDS:

TRANSPORT CATEGORY AIRPLANES

Subpart GOperating Limitations and Information

25.1529 Instructions for Continued Airworthiness.

The applicant must prepare Instructions for Continued Airworthiness

in accordance with appendix Hto this part that are acceptable to the Administrator.

The instructions may be incomplete at type certification if a program exists toensure their completion prior to delivery of the first airplane or issuance of a

standard certificate of airworthiness, whichever occurs later.

[Amdt. 25-54, 45 FR 60173, Sept. 11, 1980]
http://appendix%20h%20to%20part%2025.pdf/http://appendix%20h%20to%20part%2025.pdf/


6/43


EASA approach is almost identical to FAA

Certification Specifications (CS) section 1529 deals

with ICA.

For example: EASA CS 29 Certification Specifications

For Large Rotorcraft - OPERATING LIMITATIONS

Section 29.1529 states:

Instructions for continued airworthiness in accordance

with Appendix A to CS29 must be prepared.


7/43


NAA Policy Statements must be considered when ICA are developed.

Regulation of the Configuration, Maintenance, and Procedures (CMP) Process for Developing SFAR 88-related Instructions for Maintenance and Inspection of

Fuel Tank Systems

Some of other NAA documents may need to be considered:

AC 25.1529-1A - INSTRUCTIONS FOR CONTINUED AIRWORTHINESS OF

STRUCTURAL REPAIRS ON TRANSPORT AIRPLANES AC 120-93 DAMAGE TOLERANCE INSPECTIONS FOR REPAIRS AND ALTERATIONS

AC25.1581-1 - Airplane Flight Manual

AC120-16F - Air Carrier Maintenance Programs

AC120-42B - Extended Operations (ETOPS and Polar Operations)

AC121-16 - Maintenance Certification Procedures

AC121-16 - Maintenance Certification Procedures

AC120-76B - Guidelines for the Certification, Airworthiness, and Operational Use of

Electronic Flight Bags

AC 120-98A - Operator Information for Incorporating Fuel Tank Flammability Reduction

Requirements into a Maintenance or Inspection Program

AC121-22C - Maintenance Review Boards, Maintenance Type Boards, and OEM/TCH

Recommended Maintenance Procedures


8/43


Some of applicable CASA regulations may need to be considered when

ICA are developed.

Civil Aviation Order 20.4 (PROVISION AND USE OF OXYGEN AND PROTECTIVE

BREATHING EQUIPMENT)

Civil Aviation Order 20.18 (Aircraft equipment basic operational requirements)

Civil Aviation Order 20.11 (Emergency and life saving equipment and passenger

control in emergencies)

CASR 1998 Part 90 (Additional Airworthiness Requirements )

CASR 1998 Part 90 Manual of Standards (MOS)

CASA AC 90-1(0) (EXCLUSIONS AGAINST PROVISIONS IN CASR PART 90)

AAC 1-116 Approved Single Engine Turbine Powered Aeroplane (ASETPA)


9/43

Questions?


10/43

Lesson 7


Certif ication Maintenance Requirements (CMR) Principles

A CMR is a required scheduled maintenance task established during

the design certification of the airplane systems as an operating limitation

of the type certificate (TC) or supplemental type certificate (STC).

A CMR usually results from a formal, numerical analysis conducted

to show compliance with the requirements applicable to catastrophic

and hazardous failure conditions.

Compliance may also result from a qualitative, engineering judgment-based

analysis.


11/43


CMR Principles

1 The CMRs are required tasks, and associated intervals, developed to

achieve compliance with 25.1309.

2

A CMR is intended to detect safety-significant latent failures that would, incombination with one or more other specific failures or events, result in a

hazardous or catastrophic failure condition.

3

A CMR can also be used to establish a required task to detect animpending wear-out of an item whose failure is associated with ahazardous or catastrophic failure condition.

4 Further reading FAA AC 25-19A - Certification Maintenance Requirements
http://ac%2025-19a.pdf/http://ac%2025-19a.pdf/http://ac%2025-19a.pdf/http://ac%2025-19a.pdf/


12/43


CMR Principles

The CMRs verify that a certain failure has or has not occurred, indicate thatrepairs are necessary if the item has failed, or identify the need to inspect

for impending failures (e.g., heavy wear or leakage).

In other words, there are two main drivers for CMRs

System Safety Analysis (1309Analysis).

Impending wear-out of an itemthat could lead to a hazardous or

catastrophic

failure condition.

In both cases latent failures must be considered in the analysis.


13/43


CMR Principles

The CMRs analysis is different from the MSG-3 analysis and although both

types of analysis may produce equivalent maintenance tasks and intervals,

it is not always appropriate to substitute a CMR with an MSG-3 task.

The CMRs are to be developed and managed separately from any

structural inspections programs that are developed to meet the inspection

requirements for damage tolerance, as required by25.571, 25.1529, and

Appendix H25.4 (Airworthiness Limitations section).

Scheduled Maintenance Tasks Developments
http://schedules%20maintenance%20tasks%20developments.pdf/http://schedules%20maintenance%20tasks%20developments.pdf/http://schedules%20maintenance%20tasks%20developments.pdf/http://schedules%20maintenance%20tasks%20developments.pdf/


14/43

Lesson 7


CMR Principles

System Safety Analysis or System Safety Assessment (SSA) (1309 Analysis).

Part 23/25/27/29.1309 Equipment, systems, and installations - General and main requirements

The requirements of this section, are applicable, in addition to specific design requirements of

part 23/25/27/29, to any equipment or system as installed in the airplane. This section is a

regulation of general requirements and does not supersede any requirements contained inanother section of part 23/25/27/29.


15/43

Lesson 7


CMR Principles

System Safety Analysis or System Safety Assessment (SSA) (1309 Analysis).

Part 23/25/27/29.1309 Equipment, systems, and installations - General and main requirements

The airplane equipment and systems must be designed and installed so that any equipmentand system does not adversely affect the safety of the airplane or its occupants, or the proper

functioning.

The airplane systems and associated components considered separately and in relation toother systems, must be designed and installed so that each catastrophic failure condition is

extremely improbable and does not result from a single failure, each hazardous failure

condition is extremely remote and each major failure condition is remote.


16/43


CMR Principles

SSA (1309 Analysis)

The applicant is responsible for identifying and classifying each failure conditionand choosing the methods for safety assessment.The applicant should then obtain

early concurrence from NAA on the identification of failure conditions, their

classifications, and the choice of an acceptable means of compliance.


17/43


CMR Principles

Documentation and Handling of CMRs.

The CMR data location should be referenced in the type certificate data

sheet (TCDS).

The latest version of the CMR document should be controlled by a log ofpages approved by the NAA of the TC / STC holder or CASA.

CMRs are functionally equal to airworthiness limitations. An acceptable

means is to include CMRs in the Airworthiness Limitations section of the

airplane maintenance manual.

Any post-certification changes to CMRs should be reviewed by the same

entities that participated in the initial CMR selection and approval and must

be approved by the NAA of the TC / STC holder or CASA.


18/43

Questions?


19/43


20/43


MEL / PU Items assessment / approval

Items not covered in an MMEL - assessment / approval process

The following methods of justification can be used for those items not covered in an MMEL.

Optional Equipment - When optional equipment isfitted (over and above the

aircraft type certification equipment).

Redundant Items - If the purpose or function of a component or system can becarried out by some other item(s) of equipment.

Passenger Convenience Items - Item(s) such as galley equipment, in flight

entertainment, overhead reading lamps etc which are not addressed in the MMEL.

Any Other Items will require Qualitative and / or Quantitative Safety Analysis.


21/43


22/43



Qualitative Safety Analysis

These analytical processes assess system and aircraft safety in a subjective, non-

numerical manner, based on experienced engineering judgement.

Consider the impact that the proposed inoperative item has onall other aspects of the aircrafts operation.

The impact on crew workload and operating environment.

The impact of invoking multiple PU or MEL items.

The impact of any other existing defects.

The complexity of maintenance and/or operational procedures.


23/43

Lesson 8



Quanti tative Safety Analysis

If the operation of aircraft with an item inoperative cannot be justified by the

previous means or criteria, then a safety analysis must be carried out. This

involves a quantitative analysis of the likely risk of the worst effects that couldresult from additional failures, events and/or environmental conditions

occurring during a flight, with the particular inoperative item in question.

Assessment techniques / analysis that should be employed in this case arethe same or similar to those used for SSA (1309 Analysis).


24/43

Questions?


25/43


MAINTENANCE STEERING GROUP (MSG)

The development of maintenance programsdates to FAA Aeronautical Bulletin 7E of May

15, 1930. In the past, each air carrierproposed its own unique program.

Today, the process is a collaborative effort in which theassociated regulatory authorities, and industry work

together to develop the minimum scheduledmaintenance/inspection requirements for new andderivative aircraft, aircraft engines, and propellers.

In 1968, the Maintenance Steering Group - 1st Task Force(MSG-1) developed maintenance requirements decision

and analysis logic. MSG-1 introduced three broadprocesses to classify the scheduled maintenance

requirements.

Hard Time (HT) On-Condition (OC)Condition

Monitoring (CM)


26/43

Lesson 8




27/43


28/43



The MRB process should be used for:

(1) Transport category airplanes designed to carry 10 or more people or having a

maximum weight of 33,000 lb or more,

(2) Transport category A helicopters, or

(3) Powered-lift aircraft.

MRB may also be used for any aircraft by choice of the OEM/TCH.

An MRBR contains the minimum scheduled tasking/interval requirements for a

particular aircraft and on-wing engine maintenance programs.

MRBR should undergo an annual review by the OEM/TCH, Industry Steering

Committee (ISC), and the Maintenance Review Board (MRB) chairperson.


29/43



Scheduled maintenance, as such, cannot correct deficiencies in the inherentsafety and reliability levels of the aircraft. The scheduled maintenance can only

prevent deterioration of such inherent levels. If the inherent levels are found to

be unsatisfactory, design modification is necessary to obtain improvement.

The objectives of efficient aircraft scheduledmaintenance

To ensure

realization of theinherent safety andreliability levels of

the aircraft.

To restore safetyand reliability totheir inherentlevels when

deterioration hasoccurred.

To obtain theinformation

necessary fordesign

improvement ofthose items whoseinherent reliability

proves inadequate.

To accomplishthese goals at a

minimum totalcost, includingmaintenance costs

and the costs ofresulting failures.


30/43

Questions?


31/43


32/43


Maintenance data creation and approval

Civil Aviation Regulations 1988

CAR 2A Approved maintenance data

(2) For the purposes of paragraph (1) (a), the maintenance data are:

(e) any other instructions, approved by CASA under subregulation (4) for thepurposes of this paragraph, relating to how maintenance on aircraft, aircraft

components or aircraft materials is to be carried out.

(4) CASA may, for the purposes of paragraph (2) (e), approve instructions relating to

how maintenance on aircraft, aircraft components or aircraft material is to be carried

out.

Only CASA can approve newly created maintenance data that are not

listed in or not created by persons identif ied in CAR 2A (2).


33/43




Division 7 Exemptions from, and variations of, requirements

CAR 42ZS Granting of exemptions and approval of variations

(1) CASA or an authorised person must grant the exemption or approve the

variation if CASA or the authorised person is satisfied that granting the exemption or

approving the variation would not adversely affect the safety of air navigation.

(2) If CASA or the authorised person grants the exemption, or approves the

variation, the grant or approval may be made or given subject to such conditionsas

CASA or the authorised person thinks necessary in the interests of the safety of air

navigation.


34/43



The process used forjustifying exemptions from oramending (making variation)to maintenance data is the

same as the process usedfor creating maintenance

data (as a part of ICA)during the TC process.

The justification mustdemonstrate a soundunderstanding of

certification requirementsfor the aircraft, their relation

to and impact on theaffected maintenance data.

An assessment of theimpact of the exemption orvariation on the certificationrequirements of the aircraft

should be performed.

The outcome of theassessment should identifynecessary conditions for the

approval.

Approval can be grantedby CASA or a CAR 42ZS

authorised person.


CAR 42ZS provides an opportunity to approve variation to or exemptions fromapproved maintenance data.


35/43

Questions?


36/43

Lesson 14

System of Maintenance

TBO and maintenance schedule frequency escalations and one-off overruns

Basic principles:

Source: CAAP 42M-1(0) Approved System of Maintenance for Class A Aircraft

Airworthiness limitationsare mandatory replacement times, structural inspection

intervals, and related structural inspection tasks.Airworthiness limitations are excluded

from any escalation process by the operator.

Critical Design Configuration Control L imitations (CDCCL) - An Airworthiness

Limitation that preserves a critical feature of the aircraft needed for the Flammability

Reduction Means (FRM) or Ignition Mitigation Means (IMM) to perform their intendedfunction and prevent the occurrence of an unsafe condition.


37/43


38/43


39/43


Some of the engineering, maintenance and reliability considerations that must be

taken into account when preparing a justification for maintenance schedule frequency

escalations and one-off overruns are provided in FAA AC 121-22C Chapter 12 and Appendix

2. A summary of these considerations is provided below.

Evaluation of in-service data, both scheduled and unscheduled maintenance findings

related to the intent of the Maintenance Steering Group (MSG) task.

Weighing of the relevance and significance of findings.

Ensuring of data quality, integrity, completeness, and clarity.

Consideration of each task individually.

A review of original design and engineering specifications, as required.

http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/


40/43

Lesson 14



Some of the engineering, maintenance and reliability considerations

review of all information related to continuing airworthiness (e.g., Airworthiness

Directives, Service Bulletins (SB), in-service reports/letters, and

modifications/repairs).

Basing MRBR task evolution/optimization or deletion/addition on worldwide

representative samples that span the operating environment and age groupings of

the aircraft.

Application of statistical models to support the evolution/optimization or

deletion/addition exercise.

Measurement of task effectiveness.


41/43

Lesson 14



The same FAA AC 121-22C in Chapter 12 also provides the following statement:

If this chapter is not followed, the OEM/TCH will be limited to no more than 10

percent escalation with approved data. Further escalation is not allowed until atask is repeated and sufficient data are available.

Many OEM/TCH use this provision to incorporate one-off 10% extension option intheir ICA in order to allow for maintenance and operational scheduling flexibility.
http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/http://ac%20121-22c.pdf/


42/43

Lesson 14



The engineering, maintenance and reliabil ity considerations and

principles that must be taken into account when preparing a justification for

maintenance schedule frequency escalations and one-off overruns for Class B

aircraft are essentially the same as those previously presented for Class Aaircraft.

EASA policy on escalations is provided in IP 44 Evolution-Optimization Guidelines

and Work Instruction Maintenance Review Board team WI.MRB.00002-001 and

it is essentially the same as FAA approach.
http://ip%2044%20evolution-optimization%20guidelines%20%20issue%203.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://wi.mrb.00002-001%20maintenance%20review%20board%20team.pdf/http://ip%2044%20evolution-optimization%20guidelines%20%20issue%203.pdf/http://ip%2044%20evolution-optimization%20guidelines%20%20issue%203.pdf/http://ip%2044%20evolution-optimization%20guidelines%20%20issue%203.pdf/http://ip%2044%20evolution-optimization%20guidelines%20%20issue%203.pdf/


43/43

Questions?

development of certification maintenance requirements

Documents