6.6 Structural and Propulsion System Integrity

6.6.1    Introduction

Purpose

6.6.1.1    Aircraft Structural Integrity Program (ASIP) and Propulsion System Integrity Program (PSIP) activities occur throughout the complete aircraft life-cycle from requirements definition, design, verification / certification and in-service sustainment. Furthermore, an effective ASIP and PSIP aims to maximise holistic outcomes for Defence Capability, including safety, cost-of-ownership and availability outcomes. Notwithstanding these broader objectives, the purpose of Section 6.6 is limited to:

Describing how airworthiness-related aspects of ASIPs and PSIPs interface with the DASP.

Describing how an effective ASIP and PSIP assists the regulated community to meet their respective DASR obligations.

Providing additional guidance on elements of ASIPs and PSIPs that impact airworthiness.

Audience

6.6.1.2    Section 6.6 is relevant to:

Military Type Certificate Holder (MTCH) organisations

Continuing Airworthiness Management Organisations (CAMOs)

DASR 145 maintenance organisations

organisations involved in ASIP or PSIP activities for ADF aircraft (including CASG business units and contractor organisations).

What are Integrity Programs?

6.6.1.3    'Integrity' is defined as the level of safety, performance, durability, reliability, operability and supportability of the various air vehicle systems.

6.6.1.4    There are many threats that can compromise integrity of aircraft, including:

inadequate design or certification

material or manufacturing discrepancies

maintenance deficiencies or maintenance-induced damage

environmental degradation

operational usage or environment differing from design assumptions

procedural or management shortfalls.

6.6.1.5    Integrity programs11Such as those outlined in MIL-STD-1530D for structures and MIL-STD-3024 for propulsion systems. comprise a series of time-phased tasks that occur through development, acquisition and sustainment to counter and manage these threats. The goal of integrity programs is to ensure that the desired level of integrity is maintained throughout the life of an aircraft or system to maximise capability outcomes (ie safety, cost effectiveness and mission readiness).

6.6.1.6    Whilst the goal of integrity programs focuses on overall capability, maintaining integrity of the aircraft structure and propulsion system is an essential airworthiness principle22Refer DASP Manual Volume 1, Chapter 4, Annex A (Essential Requirements for Initial and Continued Airworthiness) product integrity requirements.. Integrity program outputs include the Airworthiness Limitations (AwL) and Instructions for Continuing Airworthiness (ICA) necessary to ensure that integrity does not reduce below the required level throughout the service life of the aircraft. As shown in Figure 1, these outputs encompass:

prevention (eg periodic application of corrosion-inhibiting compounds)

inspection (eg detection of normal or abnormal degradation)

repair / modification / replacement (eg restoring integrity through rectification of damage that exceeds a specified level, modification or retirement of components at specified life limits).

6.6.1.7    Not depicted in Figure 1 is the ongoing monitoring and periodic assessment components of integrity programs, which provide the feedback loop to ensure that the ICA and AwL remain valid in light of actual operational experience.

Figure 1: Maintaining Integrity In-Service

Defence ASIP and PSIP Policy

6.6.1.8    Separate to DASP requirements, it is Defence Policy (Engineering and Maintenance Manual (EMM) Section 7.29-7.38) that every Defence-registered aircraft type must have an effective and efficient Aircraft Structural Integrity Program (ASIP) and Propulsion System Integrity Program (PSIP).

6.6.1.9    Note that historically, Defence has implemented Engine Structural Integrity (ESI) programs that focus on the high energy, non-containable structural components within gas turbine engines. In contrast, the PSIP scope includes all propulsion system components, including engine, engine accessories and propeller. Some platforms still follow the ESI philosophy, in instances where there was minimal benefit to be gained from transitioning.

6.6.1.10    The principal objective of this policy is to support capability outcomes; including safety, capability delivery and assurance, and cost-effectiveness. On behalf of Capability Managers, Capability Acquisition and Sustainment Group (CASG) is responsible for ensuring effective and efficient programs are implemented and executed, and will appoint organisations as ASIP and PSIP managers to assist in discharging this responsibility. Typically, CASG will appoint the contractor or organisation providing aircraft / propulsion system through-life support as the ASIP and PSIP manager, but in some cases these responsibilities may be retained by CASG.

6.6.1.11    Compared to the civil sector, military operations and the Defence context typically dictate the need for more proactive and complex integrity programs. This is due to the propensity for higher operational usage variability and Configuration, Role and Environment (CRE) deviating from design assumptions, plus Defence’s desire to more closely specify and control the useful service life and maintain independence of military action. MIL-STD-1530D (ASIP) and MIL-STD-3024 (PSIP) provide exemplar frameworks for meeting the Defence Policy objectives and requirements.

6.6.1.12    Note that for brevity, the collective abbreviations SIP for the ASIP and PSIP, and SIMP for the ASI and PSI Management Plans (ie the document that describes the program) are used hereon in.

Using Section 6.6

6.6.1.13    Acknowledging the broader Defence Policy mandate and objectives outlined above, the purpose of Section 6.6 is to describe how the SIP interface with the DASP and provide guidance to assist the regulated community to meet their respective DASR obligations.

6.6.1.14    Regulations and obligations related to integrity programs are distributed throughout DASR and guidance material. Effective SIPs will therefore contribute to supporting compliance against a number of DASR 21 and DASR M requirements. This Section expands upon relevant regulation, Acceptable Means of Compliance (AMC) and Guidance Material (GM).

6.6.1.15    DASA’s scope of interest with respect to SIPs is how these programs contribute to airworthiness of the aircraft structure and propulsion system; in particular, how airworthiness is established (initial airworthiness) and then maintained in-service (continued and continuing airworthiness).

6.6.1.16    Section 6.6 is intended to be used by:

Military Type Certificate Holders (MTCHs) and Continuing Airworthiness Management Organisations (CAMOs) to understand how the SIPs for their platform should or can support their respective DASR obligations

DASR 145 maintenance organisations to understand how their activities support SIPs

CASG and industry (particularly SIP managers) to understand how SIPs interface with DASR and the associated responsibilities and requirements.

6.6.1.17    Whilst Section 6.6 describes how an effective SIP can simultaneously support MTCH and CAMO obligations, this should not be construed as suggesting that SIP execution should be fragmented within or between organisations (eg government MTCH versus CAMO, or between teams within a contracted support provider).

6.6.1.18    This Section is applicable to all aircraft operating under a Military Type Certificate (MTC), including certified category Unmanned Aircraft Systems (UAS). In accordance with DASR UAS.30(b)3, Specific Type A UAS must comply with DASR initial and continuing airworthiness regulations as directed by DASA. As outlined in the Initial and Continuing Airworthiness Requirements for Specific Category UAS Factsheet, normal practice is for the UAS operating permit applicant to propose a suitable extent of compliance for DASA approval. UAS operating permit applicants should consider tailoring and adapting the concepts outlined in this Section, based on each specific application, as part of developing their broader proposal for initial and continuing airworthiness requirements.

6.6.1.19    The remainder of this Section is structured as follows:

Section 6.6.2: SIP considerations with respect to initial airworthiness

Section 6.6.3: SIP considerations with respect to continued airworthiness

Section 6.6.4: SIP considerations with respect to continuing airworthiness

Section 6.6.5: guidance on SIMPs under DASR

Section 6.6.6: consolidated list of the main SIP-related DASR responsibilities

Annex A and Annex B: additional guidance specific to structures and propulsion systems respectively.

6.6.2    Integrity Programs and Initial Airworthiness

Type Certification Basis

6.6.2.1    The TCB is an agreed set of airworthiness requirements that a product must be compliant with in order to be issued a Military Type Certificate (MTC). The TCB will normally include a primary certification code and any supplementation required for the Defence context and Configuration, Role and Environment (CRE) (refer DASR 21.A.17A). The Defence Aviation Safety Design Requirements Manual (DASDRM) lists the primary certification codes recognised by DASA and prescribes the supplementary design requirements that must be applied as special conditions (refer DASR 21.A.16B) to account for the Defence context and CRE.

6.6.2.2    The primary certification codes recognised by DASA provide a sound basis for the safe design of structures and propulsion systems for Defence aircraft. Subject to tailoring for the Defence CRE, these codes all are sufficient to ensure that an adequate level of integrity is established during design and certification. 

6.6.2.3    However, recognised codes may require supplementation related to in service SIP monitoring and assessment, and tracking life accrual. The DASDRM Section 3 Chapters 12 and 13 provide these supplementary airworthiness design requirements and further information on type certification for structures and propulsion systems respectively. Note that these requirements are general in nature, and a deliberate assessment should be conducted based on the aircraft type, underlying airworthiness code and intended Defence CRE to determine the specific TCB wording and / or standards. Applicants are recommended to engage with DASA early in the TCB development process.

6.6.2.4    Section 7.2 also provides general information on the development of the certification basis for MTC, Military Supplemental Type Certificate (MSTC) or major change to MTC applications.

Compliance Demonstration and CRE Assessment

6.6.2.5    Along with the primary certification code and standards used, the suitability of design analysis and verification for the Defence CRE contributes significantly to the level of integrity, and therefore safety, achieved throughout the service life.

6.6.2.6    Defence rarely has direct input into the original design requirements for new aircraft, and often receives changes to a MTC and repair designs that are not exclusively designed for Defence. Unless a design has explicitly accounted for the Defence CRE, then a CRE Assessment (CREA) is required to ensure the design is safe for the intended Defence use. This is an essential step in leveraging prior Civil / Military Aviation Authority (CAA / MAA) certification for the purpose of obtaining a MTC or MSTC / major change approval (refer to DASR 21.A.20 and Section 7.2 for further information).

6.6.2.7    CREAs involve assessing whether the intended Defence CRE is compatible with the as designed CRE. For aircraft structures and propulsion systems, the CREA should examine the configuration and role related usage, loads and environment such as operating weights, altitudes, speeds; and repeated manoeuvre, dynamic, gust and thermal environments. Basic comparisons of aircraft role(s), mission mix or flight profiles (as articulated in the in the Statement of Operating Intent and Usage (SOIU)) will usually not provide adequate fidelity to identify meaningful CRE differences for structures and propulsion systems, and will therefore be insufficient in isolation. Fatigue degradation in particular can be highly sensitive to small changes in usage, loads and environment.

6.6.2.8    CREAs for structures and propulsion systems therefore usually require detailed and quantitative analysis. The SOIU should be considered a starting point for understanding the intended CRE, and an attempt should be made to better-quantify anticipated usage, loads and environment to the extent necessary, with greater fidelity than the basic information in the SOIU (eg using data from similar aircraft types). The aim should be to undertake a quantitative comparison between the as-designed and intended CRE that, for example, allows conclusions to be made regarding relative severity and impact on AwLs.

6.6.2.9    The CREA is the responsibility of the applicant for a MTC or MSTC / major change when leveraging prior certification. However, applicants should ensure that the analysis, which supports the structures or propulsion system CREA, is developed by a suitably-experienced organisation with access to the requisite data. This will likely require support from the aircraft / engine Original Equipment Manufacturer (OEM), a design organisation with sufficient technical capability and access to relevant data, and / or the expertise available within the SIP.

6.6.2.10    Inconclusive CREAs. CREAs for structures and propulsion systems sometimes cannot conclude with sufficient confidence whether the intended Defence CRE is compatible with the as-designed CRE. This often occurs during initial acquisition due to an inability to describe the intended Defence CRE with adequate fidelity. In this situation, follow-on activities should be conducted in service to obtain and assess further data, and should be managed through the SIP. Further assessment may only be possible once the ADF operational concept is fully defined and / or once a sufficient quantity of in-service data is available. In this situation a decision will need to be made as to whether:

there is a suitable basis to establish compliance for the TCB requirements affected by the inconclusive CREA outcome, or if they need to remain non compliant until follow-on activities are conducted

mitigating actions (eg additional lifing factors) are required to eliminate or otherwise minimise any associated risks so far as is reasonably practicable

there is any residual elevated risk that needs to be retained by the appropriate risk management authority.

6.6.2.11    These decisions will require experienced professional judgement and will generally be based on the level of uncertainty with the CREA and a qualitative risk assessment. Applicants are recommended to engage with DASA early when there is a lack of data or uncertainty with CREAs.

Military Type Certificate

6.6.2.12    As per DASR 21.A.41 the MTC includes:

the type design (DASR 21.A.31), encompassing:

the drawings and specifications, and a listing of those drawings and specifications, necessary to define the configuration and the design features of the product shown to comply with the TCB

information on materials, processes and methods of manufacture and assembly necessary to ensure the conformity of the product

an approved airworthiness limitations section of the ICA (as defined by the applicable airworthiness codes)

operating limitations

the Type Certificate Data Sheet (TCDS)

the TCB.

6.6.2.13    Under the DASR definition, the MTC does not include:

ICA (aside from those requirements identified as AwLs)33Refer to Section 7.2.5 (Instructions for Continued Airworthiness) for further information

off-board systems and processes, with the exception of any data which is defined as part of the AwLs (refer Section 6.6.2.24.d.(ii)), such as the SIP systems for ongoing monitoring and periodic assessment

organisational expositions and SIMPs.

6.6.2.14    As described at Section 6.6.2.3, the TCB requirements should encompass the DASDRM design requirements related to key SIP44Such as the systems for tracking life accrual and ongoing monitoring and periodic assessment. elements. Whilst compliance must be established for these TCB requirements in order to obtain a MTC, these SIP elements do not subsequently form part of the type design and MTC55A topic being covered by a TCB requirement does not automatically make that aspect part of the MTC. An example for this concept is ICA. Airworthiness codes require applicants to develop ICA in order to obtain an MTC; however, ICA (aside from the AwL section) does not form part of the enduring MTC. (with the exception of any data defined as AwLs, as discussed at Section 6.6.4.5). Nevertheless, the SIP manager, on behalf of the MTCH, should ensure that all relevant SIP elements continue to comply with the relevant TCB requirements, and that alterations to the SIP systems / processes are managed with appropriate rigour, including documentation in the DASA endorsed SIMP.

Critical Parts

6.6.2.15    Identification of Critical Parts. It is vital that Defence understands which parts of the aircraft structure and propulsion system are essential for safe flight and therefore could have a significant impact on safety if they were to fail or not perform their intended function. This is important for effective execution of the SIP and assisting regulated entities in discharging their respective obligations. Note that structural or propulsion system critical parts are not limited to those identified as being susceptible to fatigue failure, but include all parts irrespective of their potential failure mode(s) or ‘critical characteristic’. It is the consequence following failure or inability to perform the intended function that is the key factor.

6.6.2.16    The primary consideration for defining what constitutes a structural or propulsion system critical part should be the certification basis for the aircraft and propulsion system. However, noting that not all airworthiness codes are equivalent, and some are not explicit on definition of critical parts, general definitions for structural and propulsion system critical parts are provided in DASR AMC 21.A.41. Also refer to Annex A and Annex B to this Section for further information on structural critical parts and propulsion system critical parts respectively.

6.6.2.17    Structural and propulsion system critical parts should normally be defined by the responsible OEM / design organisation and it is important to understand the criteria used for this process. The applicant should ensure the definition used by the OEM / design organisation is consistent with the TCB and / or the general definitions provided in DASR AMC 21.A.41. Otherwise, a dedicated activity may be required to identify critical parts using an acceptable definition; in this instance, applicants are encouraged to engage with DASA early. 

6.6.2.18    Note that some definitions for ‘propulsion system’ include drive system. However, as per the definitions used by DASA, drive system structural critical parts should be managed under the ASIP. More generally, the OEM responsible for a given part is the best indicator of which SIP is most appropriate (ie engine or propeller OEM = PSIP and airframe OEM = ASIP). Note also that there is nothing preventing structural and propulsion critical parts being managed under an integrated program.

6.6.2.19    The applicant for a MTC or MSTC / major change should identify a list of critical parts, consistent with the TCB and the intended Defence CRE, and submit this to DASA as part of the application (refer DASR AMC 21.A.41 and AMC1 21.A.97). The definition and listing of critical parts should be included, either directly or by reference, in the SIMP. If the list of structural or propulsion system critical parts is provided as part of a broader ‘safety-critical’ item list for the aircraft type, then the parent aircraft system for each item should be identified.

6.6.2.20    Maintaining Critical Parts List. The MTCH should maintain and update the list of critical parts for the MTC based on design changes (including introduction of alternate part numbers), repairs, new / revised analysis or in service experience. Design changes and new repair designs should identify any new critical parts using the same criteria as initially used to obtain the MTC. The MTCH should also identify new critical parts as required through undertaking their continued airworthiness obligations under DASR 21.A.3A and DASR 21.A.44(c) (eg occurrences or new / revised analysis may indicate that original assumptions regarding a part’s function or potential failure mode(s) are incorrect).

6.6.2.21    Use of Critical Parts List. The regulated community can use the definition and published66The MTCH may wish to consider how the critical parts list is published so the information is readily accessible to the CAMO and maintenance organisations. list of critical parts to assist in discharging some of their respective obligations. This includes, but is not limited to, assisting with:

understanding how the broader SIP contributes to maintaining airworthiness under DASR

identification of AwLs by applicants for a MTC or MSTC / major change

ongoing management of AwLs by MTCHs (eg identifying if a new maintenance requirement should be treated as an AwL)

design and classification of modifications and repairs by design organisations

identification of critical maintenance task candidates for the purpose of determining error capture methods (DASR AMC M.A.302(d)(3))

decisions regarding deferred defects or ‘endanger flight safety’ assessments by CAMOs or DASR 145 maintenance organisations (DASR M.A.801(h) and DASR 145.A.50(a))

identification of reportable occurrences by all regulated entities.

Airworthiness Limitations

6.6.2.22    AwL Definition. AwLs are established through the certification process as being essential for preventing and / or detecting failures that may lead to an unsafe condition. AwLs may apply to many systems including the aircraft structure, propulsion system, fuel system and wiring. For aircraft structures and propulsion systems, AwLs will be associated with critical parts. A common misconception is that structural and propulsion system AwLs are only fatigue-related. AwLs are established to prevent any potential unsafe condition developing, which for structures and propulsion systems can relate to any threat including, but not limited to: fatigue, environmental degradation (eg corrosion, hot-corrosion, deterioration of organic compounds, etc), disbonding, mechanical wear, creep, flutter or other aeroelastic instability, vibration / aeroacoustics and accidental / discrete-source damage. 

6.6.2.23    Note that the term Certification Maintenance Requirement (CMR) has a specific meaning under civil airworthiness codes for transport-category aircraft (refer Section 7.2.5.3).  Applicants should therefore consider whether it is appropriate to use this term for aircraft structure and propulsion system mandatory maintenance actions, especially for civil-derivative aircraft types. 

6.6.2.24    For aircraft structures and propulsion systems, AwLs are considered to encompass (refer DASR AMC 21.A.41):

mandatory modification, retirement or replacement intervals

mandatory inspection requirements: including inspection interval(s) and the inspection method

mandatory post-flight inspections and maintenance actions associated with any use of either the rated 30 second or 2 minute one-engine-inoperative power (for rotorcraft engines with such power ratings)

the definition of the interval under a. and b. above includes:

the interval metric77For example: flight hours, landings, flight cycles, Equivalent Flight Hours (EFH), Fatigue Index (FI) / Fatigue Life Expended Index (FLEI) and engine cycles.

any algorithm, equation, factor(s) or other engineering data which must be used to calculate life accrual against the interval.

6.6.2.25    The inspection method under Section 6.6.2.24.b is considered to include the inspection technique88For example: general visual, detailed visual, ultrasonic, manual bolt-hole eddy current or automatic bolt hole eddy current., reference standards and any other inspection procedure parameters, which impact the detectable flaw size or probability of detection.

6.6.2.26    Tracking life accrual99The term ‘tracking life accrual’ is used throughout Section 6.6 in relation to measuring usage consumption relative to any type of AwL interval. against AwL intervals for structural or propulsion system critical parts often involves algorithms, damage equations, conversion factors or other similar data. Under the definition above, any data that is inextricably linked with calculation of life accrual is considered mandatory and therefore should be treated and managed as part of the AwL. Some examples include:

algorithms and look-up data which convert parametric or strain time-history data into per-flight damage increments

flight hour conversion factors for lifing parameters which are difficult to monitor flight-by-flight

engine rotational speed ‘gates’ used to define full or partial cycles

time-in-temperature matrices to track creep or thermal fatigue life accrual for engine hot-section parts

fill-in data or factors used to account for missing data. 

6.6.2.27    AwLs for aircraft structure can include mandatory actions for specific structural locations or parts (eg modification, replacement or inspection) and an overall safety-based life limit for the aircraft. The overall safety-based life limit is often referred to as the Limit of Validity for civil certified aircraft.

6.6.2.28    Identification of AwL. Structural and propulsion system AwLs should normally be defined by the responsible OEM / design organisation. The applicant for a MTC or MSTC / major change should ensure that (refer DASR AMC 21.A.41, DASR AMC1 21.A.97):

structural and propulsion system AwLs have been identified and are segregated and clearly distinguishable from other ICA

structural and propulsion system AwLs are consistent with the TCB and the intended Defence CRE

the relevant data is collated and submitted to DASA as part of the application.

6.6.2.29    Once approved by DASA, the definition and list of AwLs should be included, either directly or by reference, in the TCDS and SIMP.

6.6.2.30    Structural and propulsion system AwLs can often be highly sensitive to small changes in usage, loads and environment, and therefore a detailed and quantitative CREA is typically required (refer Section 6.6.2.8). Note that this includes all aspects of the AwL, including the algorithms, equations, factors or other data to calculate life accrual, as these too can be impacted by differences in CRE. For example, damage look-up data, factors in damage equations or fill-in data may be based on mission profile severity, which will vary between different operators.

6.6.2.31    Depending on the underlying airworthiness code, AwL terminology may differ, and mandatory requirements may not be explicitly segregated within the ICA provided by the OEM. In these cases, the applicant should define a list of structural and propulsion system AwLs consistent with the definition of Section 6.6.2.24. A well-defined list of critical parts will assist with this activity. Ensuring that AwLs are clearly identified as such, and segregated from the remainder of the ICA, assists the regulated community to fully discharge their respective obligations and ensures mandatory requirements are not altered or deferred without appropriate rigour and assurance.

6.6.2.32    Ongoing Validity of AwLs. Ensuring AwLs remain compliant with the TCB and appropriate for the Defence CRE is a MTCH continued airworthiness obligation. AwLs should be updated or introduced as required based on design changes, repairs, new / revised analysis or in service experience.

6.6.2.33    New or updated structural and propulsion system AwLs. Any change to a MTC or repair design that introduces or alters an AwL (increase or decrease) should be classified as a major change / repair (per DASR GM 21.A.91 and DASR GM 21.A.435). Any alteration of the parameters or data that are encompassed by the definition at Section 6.6.2.24 is also considered a change to the AwL.

6.6.2.34    It is important to ensure that any change or repair that impacts AwLs has explicitly accounted for the Defence CRE (as outlined in Sections 6.6.2.5-6.6.2.9). 

6.6.2.35    Changes / repairs that introduce or alter inspection-based AwLs for structures and propulsion systems require special attention as there is an inextricable link between the inspection interval(s) and method (refer Section 6.6.2.25). Design organisations should ensure that suitably-qualified and competent personnel oversee these changes / repairs and that suitable standards are used which govern the parameters that define the inspection method.

6.6.2.36    Allowing aircraft to exceed an AwL should not be approved as a change or repair unless compliance with the TCB can be demonstrated. Exceeding an AwL invariably involves an elevated level of risk (beyond that inherent in the TCB) and should only be considered where there is a compelling imperative to continue operations. Where compliance with the TCB cannot be shown, a change or repair approval is not an appropriate instrument. In this case, a Military Permit to Fly should be considered.

6.6.3    Integrity Programs and Continued Airworthiness

Investigation of Occurrences

6.6.3.1    Overview. Collection, investigation and analysis of failures, malfunctions, defects or other occurrences which cause or might cause adverse effects on airworthiness (collectively referred to as ‘occurrences’ hereafter) by DASR 21 approval holder(s) is an essential continued airworthiness activity and enables risks and hazards associated with the type design to be identified and addressed (DASR 21.A.3A(a)). 

6.6.3.2    Any occurrence that is deemed to have resulted in, or may result in, an unsafe condition must also be reported to DASA and other organisations required by the implementing regulations. Another organisation may have already deemed an occurrence as reportable to DASA, or the occurrence may be deemed reportable by the relevant DASR 21 approval holder in accordance with DASR 21.A.3A(b). 

6.6.3.3    Refer to DASR AMC 21.A.3B(b) for further detail on the definition of an unsafe condition and DASR GM 21.A.3B(b) for guidance on determining when an unsafe condition exists. DASR AMC GR.40 also provides examples of reportable occurrences. DASR AMC GR.40 Section II (Technical) and Section III (Aircraft Maintenance and Repair) are most applicable to structures and propulsion systems. Note that the DASR AMC GR.40 examples should not be used by design organisations like a ‘checklist’ for determining when a report has to be made to DASA. After receipt of reports from the primary sources of information, the design organisation will normally perform some kind of analysis to determine whether an occurrence has resulted or may result in an unsafe condition (refer guidance at DASR GM 21.A.3B(b)) and if a report to DASA should be made.

6.6.3.4    When a reportable occurrence results from a manufacturing or design deficiency, then the DASR 21 approval holder must also report to DASA the results of its investigation and any action it is taking, or proposes to take, to correct the deficiency (DASR 21.A.3A(c)(1)). Furthermore, when an Airworthiness Directive is required to correct an unsafe condition the DASR 21 approval holder must submit the proposed corrective action and / or required inspections (including the necessary details) to DASA for approval (DASR 21.A.3B(c)(1)). Further discussion on occurrence reporting and determination of unsafe conditions is beyond the scope of this Section.

6.6.3.5    Structures and Propulsion Systems Guidance. Investigation and analysis of occurrences for aircraft structure and propulsion systems often requires specific skills due to the complex nature of these systems and their associated failure modes, and the specialised design methods and tools typically employed. The MTCH should ensure that all structural and propulsion system occurrences are investigated and analysed using the expertise available within the SIP and / or the responsible design organisation (if separate).

6.6.3.6    There have been many cases throughout aviation history where catastrophic structural or propulsion system failures were preceded by little or no warning in terms of prior defects or failures. Therefore, whilst trending is important (refer Section 6.6.3.8), each individual structural and propulsion system occurrence should be promptly collected, investigated and analysed. 

6.6.3.7    Investigation and analysis should compare the actual occurrence with the assumptions made during design and type certification, and determine if the MTC (including AwL and operating limitations) or ICA need to be amended. 

6.6.3.8    The MTCH should also ensure that all relevant occurrences and data are captured by the SIP for ongoing monitoring and periodic assessment (refer Sections 6.6.3.11-6.6.3.26). This ensures that the SIP identifies any risks and hazards associated with the type design that are only evident through longer-term aggregation and trending of occurrences.

6.6.3.9    Retention of Components. Thorough and detailed examination (ie forensic techniques) is often crucial to understand the root-cause for failures in structural or propulsion system parts and prevent further failures occurring. Processes should therefore be established that allows retired, damaged or defective components to be examined as and when required.

6.6.3.10    The MTCH, and / or the responsible design organisation, should determine when an unserviceable or unsalvageable component (refer DASR 145.A.42) needs to be subject to further examination as part of an investigation. Furthermore, the MTCH or relevant design/repair approval holder should advise the CAMO and in turn, DASR 145 organisation as to when the decision has been made that such components are no longer required for investigation. Note that where an unserviceable or unsalvageable component is the subject of an occurrence report, the DASR 145 organisation should retain the component until the investigation has determined that the component is not required to be retained for further examination (refer DASR 145.A.42).

Ongoing Monitoring and Periodic Assessments

6.6.3.11    Overview. OEMs make many assumptions during design regarding factors such as operational usage, loads and environment; material performance; and manufacturing and assembly processes in order to demonstrate compliance with the TCB and develop operating limitations and AwLs.

6.6.3.12    In-service experience and additional testing or analysis may show that certain assumptions are no longer valid. Furthermore, the OEM’s assumptions cannot always specifically account for the usage and environment of every operator. This is especially the case for military aircraft as role(s), tactics and environment can vary significantly between operators and evolve over time. Operations for many ADF aircraft have historically been shown to be different and, in some cases, significantly more severe than the OEM design assumptions.

6.6.3.13    It is essential to identify, and act upon as required, any instances where the design assumptions are no longer valid throughout the service life. The MTCH is responsible for ensuring the continued integrity of the aircraft structure and propulsion system through ongoing monitoring and periodic assessment (DASR 21.A.44(c)). The purpose of these two facets include:

ongoing monitoring of service experience in order to collect the data required for, and to determine the periodicity of, assessments

periodic assessment to ensure that the assumptions made during design and certification that could affect the integrity of structural and propulsion system critical parts remain valid for the Defence CRE.

6.6.3.14    Assumptions may be identified as no longer valid for the entire global fleet, a subset of the global fleet, or just the Defence CRE. The scope of the MTCH obligation under DASR 21.A.44(c) is ensuring that the Defence type design and MTC remains compliant with the TCB. A particular focus is ensuring the operating limitations and AwLs established during certification remain valid for the Defence CRE.

6.6.3.15    The MTCH is accountable for defining the system and processes for ongoing monitoring and periodic assessment in accordance with DASR 21.A.44(c) and the TCB requirements derived from the DASDRM. For new acquisitions, the CASG Project Office will typically be responsible for ensuring the necessary systems and processes are in place and fit-for-purpose prior to obtaining a MTC.

6.6.3.16    In practice, execution of the DASR 21.A.44(c) obligation should be fulfilled through the broader SIP for each aircraft type. The SIP manager should ensure that the SIP systems and processes for monitoring and assessment continue to meet the requirements of DASR 21.A.44(c) and the TCB.

6.6.3.17    Ongoing Monitoring. Ongoing monitoring involves collecting relevant service experience data, and evaluating the data to identify significant events, exceedances of baseline assumptions, trends or anomalies that require more detailed assessment. These activities should occur continuously throughout the service life and result in the following outputs:

trigger and / or determine the frequency at which more detailed periodic assessments should be performed

identify any events, exceedances of baselines, trends or anomalies that require further investigation as part of the periodic assessments

collate and store all relevant service experience data required for periodic assessments, and future trending and analysis purposes.

6.6.3.18    Relevant service experience data collected and evaluated through ongoing monitoring should include, but is not limited to:

operational usage

failures, malfunctions, defects and other occurrences, and other unserviceabilities

maintenance findings, results of inspections and repair information

condition and health monitoring data

detailed inspection or testing of aircraft / parts with service history.

6.6.3.19    The usage data required for ongoing monitoring and periodic assessment is often extensive and complex. Integrity of structural and propulsion system critical parts for a given aircraft type can be impacted by a variety of usage and environmental factors, so collection of a large number of usage parameters is often required to compare to all the relevant design assumptions. Furthermore, the quantity of data required may vary from a statistically-representative sample through to data for all operations.

6.6.3.20    The MTCH should define the data required for the purposes of DASR 21.A.44(c) and establish the necessary arrangements with the operating and maintenance organisations to collect this data through the SIP. The SIMP should outline the specific responsibilities for each aircraft type.

6.6.3.21    Where available, and relevant to the ADF CRE, service experience from other operators should also be considered.

6.6.3.22    Periodic Assessment. Periodic assessments involves detailed analysis to test whether the assumptions made during design and certification that could affect the integrity of structural and propulsion system critical parts remain valid based on the intended and actual Defence CRE.

6.6.3.23    Periodic assessments should identify whether there is a need to update the MTC (including AwLs and operating limitations), ICA or monitoring provisions (eg tracking life accrual or health monitoring) in order to ensure continued compliance with the TCB. These subsequent updates are separate to the periodic assessment process and should be conducted in accordance with the relevant DASR.

6.6.3.24    Periodic assessments should also identify when there is a need to update the systems or processes for ongoing monitoring to ensure the necessary data is being collected.

6.6.3.25    Access to a minimum level of type design data and suitable expertise is necessary to undertake the analysis required. This should be considered by the MTCH when identifying organisations to undertake periodic assessment. 

6.6.3.26    Refer to Annex A and Annex B for more detailed guidance regarding ongoing monitoring and periodic assessment for structures and propulsion systems.

6.6.4    Integrity Programs and Continuing Airworthiness

Tracking Status of Service Life-Limited Components

6.6.4.1    Tracking against Structural and Propulsion System AwLs. The operating organisation is accountable for recording the status of service life-limited components; ie tracking life accrual against AwLs (DASR M.A.305(d)(4)). ‘Service life-limited’ parts under DASR refers to parts that as a condition of their type-certificate, may not exceed a specified operating time, calendar time, number of operating cycles, or any other approved life consumption unit. These mandatory actions are referred to as AwLs throughout this Section.

6.6.4.2    Variation in actual aircraft usage and configuration can have a significant impact on when AwL actions (such as component replacements or inspections) need to be performed. The system for tracking life accrual should ensure that individual aircraft or components (as relevant) do not exceed AwL intervals. For aircraft structures and propulsion systems, this often requires capturing and analysing a variety of usage parameters in addition to measuring accrual of AwL interval metrics such as flight hours, flight / engine cycles or landings to ensure the underlying basis of the AwL interval is not exceeded. Many AwL intervals are promulgated in ‘simple’ metrics such as flight hours or flight / engine cycles, however, actual damage / life accrual for the failure mechanism in question is usually more complex and varies based upon a range of operational factors. Therefore, additional usage parameters must often be captured and analysed to ensure individual aircraft or components are not exceeding the underlying basis of the AwL. For structural and propulsion system AwLs, the SIP for each aircraft type should support this obligation through calculation of the relevant lifing metrics and / or data analysis.

6.6.4.3    System Requirements. The philosophy and complexity of the system1010The ‘system’ includes on- and off-board hardware and software for data recording, processing and analysis, as well as the processes for data download, transfer, processing, analysis and reporting. required for tracking life accrual may vary significantly based on the certification basis, the aircraft / propulsion system type and role, and the nature of each individual AwL. Furthermore, tracking the status of structural and propulsion system life-limited critical parts for military aircraft is typically more complex than that required for civil aircraft. Additional guidance and examples for structures and propulsion systems are provided in Annex A and Annex B respectively.

6.6.4.4    The DASDRM structures and propulsion system chapters each include an essential airworthiness design requirement on tracking life accrual against critical part AwLs. The MTCH should provide the technical requirements for the system, including the usage parameters that need to be captured, with these requirements ideally being based on OEM data or advice. 

6.6.4.5    As outlined in Section 6.6.2.24.d.(ii), any algorithm, equation, factor or other engineering data which must be used to calculate life accrual is considered part of the AwL and therefore MTC. However, the broader system for tracking life accrual that is built around this data is generally not considered part of the MTC.

6.6.4.6    Tracking life accrual usually requires a complete usage history for each individual aircraft / component. Therefore, relevant data from all ground and flight operations should be captured (including pre-delivery usage if feasible) and the system should conservatively account for missing data. As identified at Section 6.6.2.26, fill-in data / factors used to account for missing data is typically considered part of the AwL. Significant quantities of missing data can impact the accuracy of life accrual, and therefore targets for valid data capture should be established and monitored1111Since the system should conservatively account for missing data, the desire to maximise the useful life (i.e. capability consideration) will likely drive the target. The MIL-STD-1530D Individual Aircraft Tracking 90% valid data capture rate of all flight data is a commonly used target that is capability and safety driven..

6.6.4.7    Depending upon the type of AwL, tracking life accrual could include both tracking total life and tracking life since last maintenance action (eg for repeat inspection intervals).

6.6.4.8    When critical parts can be transferred between aircraft or engines then the system should have the ability to track life accrual at the component level.

6.6.4.9    Life accrual for structural and propulsion system critical parts can be sensitive to small variations in usage or configuration. Therefore, the system for tracking life accrual should be subject to initial validation. Validation should test the entire system (on-board and off-board elements) in an end-to-end fashion; ie from raw / input data through to the AwL lifing metric outputs. Validation should ensure that the system produces reliable, repeatable and suitably conservative outputs so that AwL intervals are not exceeded in-service.

6.6.4.10    Even validated systems can result in incorrect outputs if subject to bad input data. Therefore, the system should include means to identify and account for missing or erroneous input data, and include quality checks of processed data. 

6.6.4.11    The period between a ground / flight operation and updated life accrual data being available will vary between platforms. In some cases near real-time update of life accrual data will be available following operations, whilst other cases will involve more lag (eg when processes require engineer-in-the-loop or complex data processing to produce life accrual outputs). Therefore, the system for tracking life accrual should take into account reporting lag to ensure that AwLs are not exceeded.

6.6.4.12    Relationship between Continuing and Continued Airworthiness Obligations. The operating organisation is accountable for ensuring that individual aircraft / components do not exceed the underlying basis of AwL intervals. This is a continuing airworthiness obligation as it relates to the aircraft complying with the airworthiness requirements in force and being in a condition for safe operation. Whilst the operating organisation is accountable, the SIP for each aircraft type should support this obligation through calculation of the relevant lifing metrics and / or data analysis when this level of complexity is required.

6.6.4.13    There is also an obvious relationship with the MTCH continued airworthiness obligation to ensure that AwLs remain valid for the Defence CRE. The interaction between the continuing versus continued airworthiness processes to ensure individual aircraft / components do not exceed the underlying basis of AwL intervals will vary between platforms and SIP philosophies. For some platforms, if SIP analysis indicates that individual aircraft may exceed the underlying basis of an AwL, then the MTCH may revise the AwL (for all aircraft) so that it fully encompasses all outliers in terms of life accrual rates. For other platforms, the CAMO may routinely adjust scheduled maintenance (ie maintenance events which correspond to when AwL actions are undertaken) based on individual aircraft life accrual rates and SIP outputs, to ensure no aircraft / components exceed the underlying basis of the AwL interval.

6.6.4.14    For structures and propulsion systems, there will often be significant overlap in terms of the usage parameters and data analysis required to fulfil both continuing and continued airworthiness functions. Therefore, a single SIP system1212Whilst DASA actively avoids using the term ‘usage monitoring’ in relation to tracking life accrual (DASR M.A.305(d)(4)), SIP ‘usage monitoring’ systems can often fulfil both responsibilities.  can simultaneously be supporting both continuing and continued airworthiness responsibilities. Where this is the case, those executing the SIP must remain cognisant of the separate DASR responsibilities the single system is supporting. 

6.6.4.15    Used Critical Parts. Acquisition of critical parts with prior (non-ADF) usage poses particular challenges for tracking life accrual against AwLs. Used critical parts can enter the ADF system in a number of ways, including acquisition of used aircraft or engines, purchase of used spares, or participation in a global parts-pooling arrangement. Even though the headline life-consumption metric will be provided for used components, the ability to understand the actual life accrual against the underlying basis of the AwL interval generally requires more detailed usage data.

6.6.4.16    Along with any relevant previous configuration and maintenance records, the CAMO should endeavour to obtain detailed usage parameters that enables the severity of non-ADF usage to be sufficiently understood. The CASG Project Office should undertake this on behalf of the CAMO for acquisition of used aircraft/engines. The CAMO may not necessarily need to hold this data if the organisation managing the system has access to the non-ADF usage data (eg global sustainment provider). If such data cannot be obtained, then the CAMO should seek advice from the MTCH and expertise available within the SIP to ensure appropriately-conservative assumptions regarding life accrual for non-ADF usage are implemented.

Aircraft Maintenance Programme

6.6.4.17    This section describes how an effective SIP can support the development and ongoing validity of relevant Aircraft Maintenance Programme (AMP) elements. Due to the broader Defence SIP Policy mandate, SIPs will often overlap with CAMO Reliability Programme (RP) obligations for the aircraft structure and propulsion system (ie SIP data and assessments can be leveraged to ensure relevant AMP elements remain effective). Therefore, CAMOs should be aware of the existing SIP scope and functions for each aircraft type, and may leverage the SIP to reduce the need for separate RP processes where appropriate. The AMP should identify where and how SIP supports the CAMO RP requirement (DASR M.A.302(f)) for the aircraft structure and propulsion system1313Per Appendix I to DASR AMC M.A.302 paragraph 6.5.2 the description of the RP should identify when the ASIP or PSIP covers monitoring of structures or propulsion systems respectively..

6.6.4.18    AMP Compliance with Mandatory Requirements. The AMP must establish compliance with mandatory requirements (ie AwLs) and identify these as such to prevent inadvertent variation1414Per Appendix I to DASR AMC M.A.302 paragraph 1.1.17 the AMP should include a cross-reference to the approved documents that contain the details of mandatory actions. To prevent inadvertent variations to mandatory tasks or intervals these items should not be included in the main portion of the AMP document, or any planning control system, without specific identification of their mandatory status.. The SIP, through the SIMP and TCDS, will provide the definition of structural / propulsion system AwLs, listing of AwLs as required, and reference to authoritative source for AwLs. This should assist the CAMO in identifying mandatory requirements (including changes thereto) and their authoritative source in the AMP. 

6.6.4.19    Note that AwLs are developed as part of the certification process and should not be extended or altered by the CAMO. Whilst there may be instances where the RP identifies the need to update AwLs, this is more often initiated through MTCH continued airworthiness obligations (refer Section 6.6.3), and in all cases should be developed and approved as a major change to the MTC.

6.6.4.20    Basis of AMP Tasks and Intervals. The AMP should be established based on anticipated ADF utilisation of the aircraft1515Refer Appendix I to DASR AMC M.A.302 paragraph 1.1.6.. When developing an AMP, the SIP can provide data and assessments that will assist the CAMO in ensuring that structural and propulsion system AMP tasks and intervals reflect anticipated ADF utilisation.

6.6.4.21    Furthermore, whilst the AMP tasks and intervals will normally be based upon the OEM’s recommended maintenance programme1616OEM information such as the Maintenance Review Board report (or equivalent) and the Maintenance Planning Document should contain reference to AwLs, however, AwLs are mandatory actions and must be treated separately to the other (recommended) elements of the maintenance programme., the CAMO may need or desire to introduce additional or alternative instructions. For aircraft structures and propulsion systems, the SIP expertise, data and assessments can provide the supporting information for alternative and / or additional tasks and intervals proposed by the CAMO (DASR AMC M.A.302(d)).

6.6.4.22    Periodic Review and Amendment of the AMP. The AMP must be subject to periodic review to ensure it remains valid in light of operating experience1717Per Appendix I to DASR AMC M.A.302 paragraph 5.2 a review of the detailed [AMP] requirements should be carried out at least annually for continued validity in the light of operating experience. This includes any changes to assumed utilisation, configuration, role or operating environment., instructions issued by DASA and any new and / or modified maintenance instructions promulgated by the MTCH or other design approval holder (DASR M.A.302(g)). For aircraft structures and propulsion systems, the SIP expertise, data and assessments can support the periodic review and amendment of relevant AMP elements. 

6.6.4.23    Some RP approaches used for other aircraft systems may not be appropriate for structures and propulsion systems. For example, systems approaches for establishing alert levels / performance standards, use of mean-time-between-failure style metrics, and statistical analysis techniques will usually not lead to meaningful or effective outcomes for structural and propulsion system integrity. Therefore, leveraging the SIP expertise, data and assessments to support periodic review and amendment of relevant AMP elements can lead to more effective and robust outcomes and avoid duplication of effort.

6.6.4.24    To support periodic review and amendment of relevant AMP elements, the SIP should assess all relevant service experience and compare this to the assumptions that underpin the AMP intervals and tasks to ensure they remain valid. Relevant service experience data should include, but is not limited to:

operational usage

occurrences and other unserviceabilities

maintenance findings, results of inspections, and repair information

condition and health monitoring data.

6.6.4.25    Where available, and relevant to the ADF CRE, service experience from other operators should also be considered.

6.6.4.26    Note that despite the separate obligations, there is a degree of commonality between the monitoring and assessments to support ongoing validity of relevant AMP elements and those required under DASR 21.A.44(c) (see Section 6.6.3). Whereas the objective of DASR 21.A.44(c) is to ensure the MTC remains compliant with the TCB, the objective of DASR M.A.302(g) is to ensure the maintenance tasks and intervals implemented through the AMP remain valid for the individual operator. Nevertheless, similar expertise, data and assessment methods are required in both cases. Therefore, the SIP systems and processes (as overseen by the SIP manager) should be able to support both sets of obligations within the scope of the aircraft structure and propulsion system. The CAMO should ensure that the SIP is cognisant of their DASR M.A.302 requirements.

6.6.4.27    Condition and Health Monitoring. SIP condition monitoring and health monitoring elements can also support the DASR RP requirement for certain aircraft systems or components and in turn contribute to ensuring the ongoing effectiveness of the AMP. Condition / health monitoring elements can be comprised of many different techniques that will vary between the system or component(s) being monitored. Examples for structures and propulsion systems may include:

scheduled inspection of general component condition (including through non-destructive and remote visual inspections techniques),

vibration monitoring

monitoring of parameters such as oil / fluid / gas temperatures and pressures

performance monitoring

wear debris analysis

oil condition monitoring

embedded sensors to detect structural failures or redistribution of loads.

6.6.4.28    Condition / health monitoring requirements may be promulgated through ICA, in which case the CAMO would be expected to incorporate these requirements in the AMP, or they may be implemented as an additional measure to support reliability, availability and maintainability goals. 

6.6.4.29    Note that condition / health monitoring for the purposes described in this section should not be conflated with Structural Condition Monitoring (SCM) under the MTCH DASR 21.A.44(c) obligation (refer to Annex A for further information on SCM). These two concepts serve separate purposes, but are related in that data from condition / health monitoring techniques may be a subset of the source data for SCM.

Recording Operational Usage

6.6.4.30    In addition to basic aircraft record keeping and tracking life accrual, the collection of operational usage data is required to support the MTCH obligation to undertake ongoing monitoring and periodic assessment (DASR 21.A.44(c), refer Section 6.6.3).

6.6.4.31    The nature of the usage data required will vary significantly between aircraft and propulsion system types and roles. The MTCH should define the data required for supporting the DASR 21.A.44(c) obligation, including any technical requirements for the system to collect the data. These requirements should ideally be based on OEM data or advice.

6.6.4.32    The operating organisation is responsible for ensuring that the required usage data is collected through the continuing airworthiness record system (DASR M.A.305(c)).

6.6.5    Structural / System Integrity Management Plan (SIMP)

Purpose of SIMPs under DASR

6.6.5.1    SIMPs are a key document that assists the regulated community in the following two main ways:

SIMPs provide a consolidated reference for key structural and propulsion system information such as the relevant airworthiness design requirements and standards, certification outcomes and the definition and source for critical parts and AwLs.

SIMPs document how the SIP contributes to supporting a number of MTCH and CAMO DASR obligations. From this perspective, SIMPs should be considered subordinate to the Type Continued Airworthiness Exposition (TCAE), Continuing Airworthiness Management Exposition (CAME) and AMP document. The relevant sections of the TCAE, CAME and AMP should refer down to SIMPs and the relevant sections of the SIMPs should refer to the regulation(s) the content is supporting.

6.6.5.2    SIMPs are therefore considered AMC under DASR.

SIMP Content, Structure and Management

6.6.5.3    Given the purpose of SIMPs under DASR outlined above, DASA’s policy is that it will endorse all SIMPs. However, SIMPs serve a broader purpose under Defence Policy1818Namely to document the SIP basis and philosophy, all SIP systems and processes, a broad range of relevant data, and information on SIP investigation and development tasks., therefore, not all content will be directly relevant to the DASP.

6.6.5.4    The SIMP content that requires DASA endorsement is listed in Table 1. For ease of review and management, DASA recommends that this content be contained in a dedicated section of the SIMP. All other SIMP content should be managed by the SIP manager in coordination with CASG.

6.6.5.5    DASA expects that SIMPs will be maintained by the SIP manager, and that the MTCH and CAMO will have reviewed the content listed in Table 1 that is relevant to them prior to SIMPs being submitted for DASA endorsement. Best practice is to ensure the sections of the SIMP that are relevant to either the MTCH or CAMO are clearly identified.

6.6.5.6    An indicative SIMP amendment process is shown below in Figure 2. Note that since SIMPs serves a broader purpose under Defence Policy, DASA endorsement should not be viewed as the final step, and SIMP approval should be provided by a suitable Defence representative (notionally a senior Defence engineer within the CASG System Program Office).

Table 1: SIMP Content Requiring DASA Endorsement

Figure 2: Indicative SIMP Amendment Process

ASIMP Volume 2 / Force Structural Maintenance Plan (FSMP)

6.6.5.7    Discussion on SIMPs until this point has been in reference to the ASIMP Volume 1 and PSIMP.

6.6.5.8    Some aircraft types also use an ASIMP Volume 2 / FSMP. These vary in scope, but typically consolidate information such as structural classifications and / or listing of critical parts, and details (including reference to substantiating and supporting data) of locations identified through analysis, test or service experience that require modification, inspection or repair. DASA supports use of an ASIMP Volume 2 / FSMP as they are a valuable document for ASIP stakeholders, however, DASA does not have any expectation that they should be maintained for every aircraft type.

6.6.5.9    In the capacity outlined above, an ASIMP Volume 2 / FSMP should simply be a consolidated reference of previously-approved design data, and therefore does not require DASA endorsement or approval.

6.6.5.10    The only exception may be where the ASIMP Volume 1 identifies the ASIMP Volume 2 / FSMP as the authoritative source for structural AwLs. This may be the case for some legacy platforms where the ASIMP Volume 2 was historically used to approve and publish AwLs (ie there is no other authoritative ‘source’ document(s) to refer to). In this case, the ASIMP Volume 2 / FSMP should clearly distinguish AwLs from other structural maintenance requirements. Furthermore, moving forward they should not be used as the vehicle to approve new or updated AwLs, rather they should reference the separately approved design data. In this capacity the ASIMP Volume 2 / FSMP should be treated like other manuals issued by the MTCH (DASR 21.A.57). As noted under DASR AMC 21.A.57, approval and issuing the manual may be separate to approval of the technical content (ie approval of the AwLs).

6.6.6    SIP-Related DASR Responsibilities

6.6.6.1    The main SIP-related DASR responsibilities are consolidated by organisation in Table 2.

6.6.6.2    Whilst SIP-related DASR responsibilities are distributed across different organisations, DASA expects that each SIP will continue to be managed and led by a single organisation (ie SIP manager appointed by CASG). Organisational responsibilities are listed below so that each regulated entity understands what they are accountable for, and so SIP managers can understand how their SIP contribute to supporting various obligations under DASR.

Table 2: Consolidated SIP-Related DASR Responsibilities