26 September 2018

ADVISORY CIRCULAR

AC 005 / 2018

MANAGEMENT OF DEFECTS

MANAGEMENT OF DEFECTS

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An Advisory Circular is issued by the Authority to promulgate important information to the Defence Aviation community, but does not mandate any action. This includes informing the community on aviation safety / airworthiness matters, information that enhances compliance understanding for existing regulation, or policy guidance for aviation issues not yet regulated that requires further understanding.

Audience

This Advisory Circular (AC) applies to all DASR regulated entities exercising roles or

responsibilities associated with Operational, Initial/Continued and Continuing

Airworthiness.

Purpose

This AC describes how the Defence Aviation Safety Regulation (DASR) supports

military aviation flexibility. This is important as the Government has expectations on the

ADF to satisfy preparedness requirements and also meet short notice tasking. This AC

will convey how DASR maintains close alignment with contemporary aviation safety

conventions, however, when reasonably practicable also provides flexibility within the

Defence Aviation Safety Framework to achieve necessary outcomes. This AC replaces

AC 005/2017.

For further information

For further information on this AC, contact ACPA DASA.

Status

Version Date Approved By Details

1 26 September 2018 DACPA Initial release

Unless specified otherwise, all regulation referenced in this AC are references to the Defence Aviation Safety Regulation (DASR).

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1. Reference Material

1.1. Acronyms

AC Advisory Circular

AMC

AFHRS

ACRE

CAM

Acceptable Means of Compliance

Airframe Hours

Authorisation of non-standard Configuration, Role and Environment

Continuing Airworthiness Manager

CAMO

CASA

CDL

CoA

CRS

DASA

Continuing Airworthiness Management Organisation

Civil Aviation Safety Authority

Configuration Deviation List

Certificate of Airworthiness

Certificate of Release to Service

Defence Aviation Safety Authority

DASR

Defence AA

EASA

EMAR

Defence Aviation Safety Regulation

Defence Aviation Authority

European Aviation Safety Agency

European Military Airworthiness Requirements

GM

ICA

ICAO

MAO

MDOA

MEL

MMEL

MAO

MAO-AM

MPTF

MTCH

NMAA

OEM

PTF

SFARP

Guidance Material

Instructions for Continuing Airworthiness

International Civil Aviation Authority

Military Air Operator

Military Design Organisational Approval

Minimum Equipment List

Master Minimum Equipment List

Military Air Operator

Military Air Operator Accountable Manager

Military Permit to Fly

Military Type Certificate Holder

National Military Airworthiness Authority

Original Equipment Manufacturer

Permit to Fly

So Far As Reasonably Practicable

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SPA

SPO

U/S

WHS

Specific Approvals

System Program Office

Unserviceability

Work Health Safety

1.2. Definitions

1.2.1. Endanger Flight Safety. Refer to AMC1 to 145.A.50(a) which states: ‘Endanger flight safety means any instance where safe operation could not be assured or which could lead to an unsafe condition. It typically includes, but is not limited to, significant cracking, deformation, corrosion or failure of primary structure, any evidence of burning (including overheating), electrical arcing, significant hydraulic fluid or fuel leakage and any emergency system or total system failure. An AD overdue for compliance is also considered a hazard to flight safety.’

1.3. References

1.3.1. AAP 8000.011 Defence Aviation Safety Regulations

1.3.2. Advisory Circular AC003/2017 DASR Implementation of Military Permits to Fly

1.3.3. Work Health and Safety Act 2011 (WHS Act) and Work Health and Safety

Regulations 2011 (WHS Regulations).

1.3.4. AC 002/2016 – Aviation Command Responsibilities under DASR.

1.3.5. AAP 6734.001 – Defence Aviation Safety Manual.

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2. Responsible agencies or individuals

2.1. Remaining cognisant of the wide ranging audience of this AC, the MAO and

CAMO are the most likely proponents for the use of the processes described in this AC

for the management of defects. The MAO/CAMO should therefore establish in-service

procedures for the management of Defects in accordance with the applicable DASR

AMC that reflect the central role of the MAO/CAMO and authorised staff.

3. Background

3.1. The necessity to operate ADF aircraft with an existing defect is nothing new to

the ADF and has not changed with the introduction of DASR. This is particularly

relevant in situations where commanders are expected to operate Defence aircraft at

higher levels of risk to achieve directed mission objectives in support of Australia’s

national interests.

4. Scope

4.1. This AC brings together the requirements of several regulations. For example,

DASR M.A.301(a), where a CAMO is required to have a system for the management of

deferral of defects, DASR 21.A 701 MPTF and DASR SPA.10 where the MAO is

required to have a system for the management of Command Clearances. The focus of

this AC is for the management of defects where the aircraft has been released to 145

maintenance organisation and there is a defect that needs to be managed. This AC also

includes guidance on how Command Clearances may be used to manage defects in

these circumstances. Command Clearances can also be utilised for other purposes as

per DASR SPA.10. where the scope of this AC may not be applicable

4.2. Decisions made by the Aircraft Captain. DASA.ORO.55 Aircraft Captaincy,

details the responsibilities of the Aircraft Captain whilst in charge of the aircraft. These

are separate to the guidance provided by this AC, and the Command Clearance

requirements of DASR SPA.10.

5. Continuing Airworthiness Military Context – Flexibility Provisions

5.1. Deferred Defect effect on CoA. The premise of operating aircraft safely is

centred upon the concept that each individual in service airframe must be airworthy to

operate. Simplistically, individual aircraft are airworthy provided the Certificate of

Airworthiness (CoA) remains valid. A defect renders an aircraft’s CoA invalid and

therefore the airframe cannot fly until the CoA is revalidated. The CoA can be

revalidated by a number of methods including, rectifying the defect IAW Instructions for

Continuing Airworthiness (ICA), deferral of the defect or approval of a Command

Clearance.

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5.2. When an aircraft is appropriately ‘authorised’ to fly with the defect existing, it is

known as a Deferred Defect. Defects can be deferred via provisions of the DASR, such

as ICA, Minimum Equipment Lists (MELs) or Configuration Deviation Lists (CDLs).

MELs and CDLs allow the aircraft to be operated with defective equipment/item(s) and

uninstalled components respectively. Deferred Defects can be thought of as

supplementing the invalid CoA thereby restoring the original CoA. This process can also

be applied to platforms operating under a MPTF prior to the issuance of a Type

Certificate. Figure 1 below, depicts this analogy.

Figure 1: Military Flexibility – MEL and No MEL

5.3. Minimum Equipment List. In Figure 1 both defect #1 and #2, render the CoA

invalid. Due to constraints (normally time), an approved MEL for that aircraft type/tail

has been used to defer the defects. The CoA is now valid (assuming all defects cleared)

and the aircraft is considered serviceable. A MEL can be quite extensive and cover a

range of situations; however, a MEL can never cover every situation and is constrained

to known, predicted scenarios. Further, there will be occasions when the conditions of

the MEL to defer a defect cannot be satisfied.

5.4. No Minimum Equipment List or Not on MEL. When an aircraft within the ADF

does not have an approved MEL or the situation in question is not listed in the approved

MEL, defects that do not endanger flight safety as assessed by the 145 may be

deferred. In Figure 1 defect #3 has been assessed as not endangering flight safety and

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been recorded as a Deferred Defect. The CoA is now valid (assuming all defects

cleared) and the aircraft is considered serviceable.

Figure 2: Military Flexibility Solution – MEL, No MEL and MPTF

5.5. Military Permit to Fly. The DASR flexibility provision, as depicted in Figure 2,

allows the CoA to be supplemented by the use a MPTF. The MPTF does not replace

the CoA, rather the MPTF(s) supplement the CoA in a similar vein to the use of a

MEL/CDL thereby restoring/re-validating the CoA. The concept of MPTFs

supplementing the CoA does come with trade-offs and additional requirements1 which

are not covered within the scope of this AC.

5.6. Even with a DASR flexibility provision in place for MPTF/CoA management, there

will still be times when the Continuing Airworthiness framework does not provide the

necessary flexibility to meet National interests. For example, there may simply not be

enough time to achieve the issuance of a MPTF and the essential nature of the mission

requires the use of the aircraft.

5.7. Command Clearance. Defence has added flexibility to satisfy national interests.

DASR SPA.10 Command Clearance provides this flexibility as a provision of

Operational Airworthiness. Command Clearance is a flexibility provision used for

1 Advisory Circular AC003/2017 DASR Implementation of Military Permits to Fly – refer paragraph 11.4

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circumstances that have been deemed essential and is implemented in parallel with

continuing airworthiness processes where the expected duration of operation under a

Command Clearance would reasonably enable alternate continuing airworthiness

flexibility provision to be approved. Because time is a factor for invoking SPA.10,

engineering solutions may not necessarily have been exhausted. Command Clearances

still require compliance with WHS legislation in that the aviation safety risk must first be

eliminated so far as reasonably practicable (SFARP) and if not able to be eliminated

then minimised SFARP.

5.8. The issuance of a Command Clearance from the Military Air Operator –

Accountable Manager (MAO AM) or Delegate may occur for circumstances where the

Continuing Airworthiness framework cannot support military flexibility requirements. In

these cases, where a Command Clearance is issued, the CoA is not revalidated, rather,

after consideration of the mission requirements which dictate that the flight must occur,

the aircraft is permitted to fly with a known condition that could have the potential to

endanger flight safety. The essential nature of the mission that justifies the issuing of a

Command Clearance is proportionate with the assessed risk of operating with the

condition that may endanger flight safety. Figure 3 below depicts the provisions of

SPA.10 Command Clearance when used to manage a defect.

Figure 3: Military Flexibility – MEL, No MEL, MPTF and Command Clearance

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5.9. The key difference between the MPTF and Command Clearance is that the

MPTF is an Initial Airworthiness instrument subject to DASA approval and issue,

whereas a Command Clearance is an Operational Airworthiness approval via the

command chain. In both cases, MPTF and Command Clearance are valid approvals

and must contain conditions and limitations that ensure safety. For airworthiness

accountability and management, the MAO must ensure the appropriateness of all

MPTFs and Command Clearances.

6. Authorisation for the Management of Defects

6.1. Military Flexibility – What is the process? The flow chart at Enclosure 1 has

been developed to guide commanders and personnel working within the DASR

framework through various approaches, tools and options available to manage defects

to achieve ADF requirements.

6.2. Flexibility Provision 1 – MEL/CDL. Consult the MEL/CDL to identify if deferral

of the defect is permissible. The MEL/CDL may prescribe certain conditions to be

satisfied and if the MAO AM (or delegate) endorses the proposed deferral, the CAM (or

delegate) may approve the deferral. The deferred defect is documented in the aircraft

technical log, including deferment period and any associated limitations. The aircraft is

then able to be operated with a valid CoA.

6.3. Flexibility Provision 2 – No MEL/CDL. If no MEL/CDL exists, or the defect is

not covered by the MEL/CDL this provision provides the ability to defer the defect.

Flexibility Provision 2 requires an assessment to be carried out by an appropriately

authorised certifying staff, to determine if the defect does/does not ‘endanger flight

safety’2. There are no limitations on who may be consulted to make this determination,

including appropriate aircrew, technical or engineering staff. The broad requirements of

this assessment including some examples are within the definition at the beginning of

this AC. If further clarity is required for a specific FEG or aircraft, a CAM (or delegate)

may consider including this as part of the system implemented for the management of

defects.

6.4. If the assessment determines the defect does not endanger flight safety the

decision is then passed to the CAMO delegate for agreement to defer the defect. CAMO

agreement involves considering and accepting the potential logistics consequences

such as availability of spares and potential higher cost to rectify the defect at a later

date as well as obtaining operational endorsement of the deferral. The CAM may

choose to delegate the responsibility for logistical and operational decisions, noting

accountability cannot be delegated. Typically, appropriately experienced and authorised

2 An ‘endanger flight safety‘ assessment shall be conducted in accordance with AMC1 to 145.A.50(a)

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engineering and technical members within ADF squadrons would be expected to be

suitable candidates.

6.5. If the CAM (or delegate) agrees to the deferment, then the deferred defect is

documented in the aircraft technical log, including the deferment period and any

associated limitations.

6.6. The aircraft technical log must accurately record the CAM (or delegate) deferred

defect logistical decision/authorisation. Under this flexibility provision the CAM retains

accountability for the decision to defer the defect and the DASR 145 organisation is

accountable for the ‘endanger flight safety’ assessment and correctly annotating the

technical log to record the decision.

6.7. Flexibility Provision 3 – CAMO Management. If the outcome of the No

MEL/CDL assessment results in the DASR 145 authorised certifying staff determining

that the defect would/could possibly endanger flight safety, or if there is insufficient data

to inform the decision, the CAMO has the following options:

6.7.1. Additional Data provided. The CAMO may be able to provide additional data to

the DASR 145 to re-consider, on merit, the 'endanger flight safety' assessment. The

CAMO may have access to additional data (OEM, design, operational) not available to

the DASR 145. For example, the CAMO may be able to provide updated ICA, prior to

the scheduled publication amendment. The DASR 145 organisation can use any

credible data (referencing all data used) in determining the endanger flight safety

assessment but are always within their right after appropriate consideration of the data

to refer back to the CAMO i.e. make a ‘yes’ (does endanger flight safety), ‘unsure’ or

‘insufficient data’ determination. The No MEL/CDL flexibility provision can be re-entered

if the 145 organisation re-assessment determines the ‘issue /defect’ does not endanger

flight safety.

6.7.2. Rectify the defect. The CAMO may decide not to defer the defect and task a

DASR 145 maintenance organisation to rectify the defect. In these cases the CAMO

should notify/task an appropriate DASR 145 organisation to rectify the aircraft.

6.7.3. Approved repair. Seek an approved repair from a MDOA holder, who will issue

an approved repair, approval to operate with unrepaired damage and/or modified flight

conditions. The CAMO receives approval documentation (from an MDOA holder) and

issues/updates ICA that is provided to the 145 organisation to incorporate any repair

and record appropriately.

6.7.4. Life extension. If appropriate, a life extension may be provided by:

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6.7.4.1. Repackage life within Airworthiness Limitation, as required by DASR

M.A.301(a)(3).

6.7.4.2. Extension of a non-Airworthiness Limitation servicing by the CAMO based on

reliability data.

6.7.5. Military Permit to Fly (MPTF). Seek a MPTF IAW DASR 21.A.701. The MPTF is

issued, the decision is recorded appropriately and the aircraft technical log is updated.

Advisory Circular AC003/2017 should be consulted for detail on the MPTF process.

6.8. Command Clearance. If the issue cannot be solved utilising the continuing

airworthiness flexibility provisions, the CAMO may engage the MAO AM or delegate.

Not having sufficient time, is likely to be a common factor preventing one of the

continuing airworthiness flexibility provisions from being applied to resolve the issue.

The dotted red line at enclosure 1 signifies the departure from Continuing Airworthiness

regulation to Operational Airworthiness regulation for the specific issue only.

Importantly, the remainder of the aircraft has to remain compliant with Continuing

Airworthiness regulation. Provisions must be put in place to enable the aircraft to be

returned to management under Continuing Airworthiness provisions as soon as

practicable.

6.9. In ideal circumstances, conditions that require a MPTF would be managed via a

MPTF however, if all options available through continuing airworthiness flexibility

provisions have been exhausted, and where there is insufficient time to process a

MPTF application, and the essential nature of the mission has been established, a

Command Clearance as allowed by DASR SPA.10 may be exercised by the MAO AM

or delegate.

6.10. The process for a Command Clearance is modelled on the WHS requirements

with the ultimate goal of eliminating the hazard/risk SFARP and if not able to eliminate,

then to minimise the risk SFARP. Additionally, decisions are to be made at the most

appropriate level including whether the cost of eliminating or minimising the risk is

grossly disproportionate to the risk.3 The process contains the flowing steps:

6.10.1. Gaining reasonable knowledge of Hazard and Controls. All reasonable

knowledge of the issue should be obtained. There is no limitation placed on the MAO

AM or delegate in where to obtain or who may provide information. Ultimately the

Commander or delegate needs to be satisfied that all reasonable effort was made,

within context, to enable further assessment to eliminate the Hazard/Risk and, if not

able to eliminate, a risk assessment is conducted and controls applied to minimise the

risks SFARP.

3 WHS ACT 2011, Part 2, Division 1, Sections 17 and 18.

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6.10.2. Eliminate the Hazard / Risk. If the hazard/risk is eliminated through

operational controls or limitations instigated by the MAO AM delegate, then no risk need

be retained by the operator. The aircraft is permitted to fly with a known condition that

potentially ‘endanger flight safety’ after consideration of the essential nature of the

mission and the elimination controls / limitations have been documented in the aircraft

technical log.

6.10.3. Risk Assess the Hazard / Risk. Command Clearance allows for

operation at differing risk levels than those associated when complying with the DASR

Initial and Continuing Airworthiness requirements i.e. above the red line of enclosure 1.

In these circumstances the decision to ‘proceed knowing the level of risk’ should be an

informed one, and retained as appropriate through a risk management framework such

as AFSM and AVRM as per the DASM.

6.10.4. Mitigate the Risk. After completion of the risk assessment the controls

and limitations must be implemented to meet the requirements of minimising the risk

SFARP as per DASM (and the WHS Act). Any identified controls / limitations must be

appropriately documented in the aircraft log.

6.10.5. Command Clearance Issued. The Command Clearance may be issued

by the MAO AM or delegate subject to the aviation safety risk being eliminated SFARP

and if not able to eliminate then minimised SFARP.4

6.11. Where a Command Clearance is used to permit flight with a defect or other

configuration change, it should be documented in the aircraft technical log, including

deferment period and any associated limitations. The aircraft technical log must be

updated to record the Command Clearance decision/authorisation. In this case the

DASR 145 organisation is not taking accountability for the Command Clearance

decision itself, the DASR 145 organisation is still responsible for correctly annotating the

technical log to record the decision on behalf of the MAO/CAMO as tasked/directed.

6.12. Importantly, a Command Clearance is not a Deferred Defect. However,

MAO/CAMO use of the Defence deferred defect process to update the aircraft technical

log and provide robust recording and tracking mechanisms is considered effective when

the Command Clearance has been issued to manage a defect within the 145

maintenance organisation.

4 Regardless of elimination or minimisation, both require a Command Clearance as the controls and

limitations are authorised by the MAO AM or delegate.

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6.13. ADF implementation. To satisfy the requirements of DASR SPA.10, the MAO

must have a system in place that specifies appropriate procedures, delegations and

oversight for Command Clearances. Consideration needs to be applied to delegations,

compliance with the DASR.SMS, DASM and multiple applications of the continuing

airworthiness flexibility provisions and Command Clearance.

7. Reporting/Recording Actions

7.1. Reports required - Nil

7.2. Recording action – Nil

8. AC Currency

8.1. This AC will remain current until cancelled by DASA.

Original SignedSeptember 2018Director - ACPA, DASA

Enclosure

1. Management of Defects – Flow Chart

Enclosure 1 to AC 005/2018

26 September 2018