10.1 DASR SPA.40 Defence Long Range Operations (DLRO) requires Military Air Operators (MAO) to establish a DLRO management system for Defence aircraft. The AMC and GM to DASR SPA.40 provides the context under which technical assessment of Defence aircraft for suitability to conduct DLRO will be undertaken, and in-service DLRO management requirements will be established, as part of the MAO's risk assessment considerations. DASR SPA.40 applies to fixed wing multi-engine turbine aircraft operated by Defence that may carry Defence personnel on long range flights. The approved aircraft Statement of Operating Intent and Usage (SOIU) forms the basis for applicability and the MAO is responsible for determining which aircraft should be managed under DLRO.
10.2 The determination of whether a Defence aircraft is subject to DLRO management is a capability and safety decision for the MAO. To support informed risk-based decision making on the technical suitability of a Defence aircraft to conduct DLRO, technical assessment of affected Defence aircraft must be conducted.
10.3 DLRO is, conceptually, similar to civil Extended Diversion Time Operations (EDTO) and consequently the Authority employs the EDTO airworthiness design requirements as a benchmark against which to assess Defence aircraft for DLRO. However, some important context for Defence aircraft must first be established to ensure that the civil standards are applied in a pragmatic manner. EDTO requirements apply only on specific routes where the aircraft operator is at the ‘higher consequence’ end of the civil aviation operations spectrum (ie EDTO normally only applies to ‘regular public transport’ and charter operators operating at significant distances from diversion airfields). For example, while EDTO may be prescribed for a Qantas A330 operating on a designated EDTO route in civil airspace, the same aircraft type operated by a private organisation without fare paying passengers on the same route will not be required to comply with EDTO requirements. Consequently, aviation industry ‘good practice’ for EDTO does not include strict compliance with EDTO requirements for all aircraft undertaking these operations.
10.4 Similarly, the Authority does not prescribe compliance with the civil EDTO requirements. Rather, the EDTO standards are used as the basis against which Defence aircraft technical aspects can be evaluated to identify hazards and associated risk treatments, and provide the MAO with a comprehensive basis upon which to make informed risk-based decisions in support of DLRO approval. While technical risk treatment would usually be pursued as the initial step in resolving shortfalls against prescribed design requirements, in this instance, operational controls may be equally valid and provide the same benefit in terms of safety outcomes. Therefore, it may be possible for the risk associated with DLRO to be minimised so far as is reasonably practicable without enforcing strict compliance with the civil EDTO standards for aircraft design or implementing potential design treatments for identified shortfalls. Consequently, the Authority has adopted the following approach to prescribing design requirements for DLRO:
an analysis of the aircraft design features that support safe DLRO must be conducted against the civil EDTO standards;
shortfalls against the civil EDTO standards, and potential design risk treatments, must be identified;
the shortfalls must be communicated to the MAO for a determination on whether operational controls would be effective in treating the risk, or whether design treatment will be required; and
a continuing airworthiness program (ie a system of maintenance and a performance monitoring program) must be established to ensure that the design features that support safe DLRO are not compromised in service.
10.5 Finally, contemporary civil approaches to EDTO approvals accommodate the differences in hazards posed by one-engine inoperative operations at extended diversion times in aircraft with two engines and aircraft having more than two engines, through the application of more onerous requirements for two engine aircraft. Given the similarity in context between EDTO and DLRO, a similar approach for Defence aircraft is appropriate. Consequently, this chapter presents distinct Authority prescribed requirements for undertaking DLRO assessments on Defence aircraft having two and more than two engines respectively.
10.6 This chapter presents Authority prescribed design and continuing airworthiness requirements for Defence aircraft that are subject to DLRO management.
10.7 This section presents the Authority prescribed DLRO design requirements for Defence aircraft.
10.8 Design Requirement (Essential). Where the MAO has determined that a Defence aircraft having two engines is subject to DLRO management, the aircraft design must be evaluated against the design requirements prescribed in one of the following:
CASA CAAP 82-1 – Extended Diversion Time Operations, or
FAR Part 25 Appendix K – Extended Operations, in conjunction with FAA AC 120-42B – Extended Operations, or
EASA AMC 20-6 – Extended Range Operation with Two-Engine Aeroplanes ETOPS Certification and Operation.
10.9 The airworthiness design requirements for EDTO defined by the CASA, FAA or EASA provide an appropriate benchmark against which to establish the level of safety afforded by two engine Defence aircraft for DLRO. Defence aircraft designs must be evaluated against the requirements defined in the civil standards at paragraph 10.8 to identify shortfalls, characterise associated risks, and identify potential technical risk treatments to eliminate or minimise the risk. The outcomes of this evaluation, including risk treatment options and any residual risk, must be communicated to the MAO to support informed risk-based decisions on the aircraft's suitability for conducting DLRO.
10.10 Where even a ‘basic’ evaluation of a two engine Defence aircraft design against the civil EDTO requirements cannot be accomplished, the Authority must be petitioned for agreement on a suitable benchmark and means of establishing compliance for the DLRO technical evaluation on a case-by-case basis. Examples might include:
a military aircraft design for which long range operations was not originally considered and for which no design data to substantiate claims exists (eg for engine reliability); or
the design complies with a bespoke suite of requirements that do not correlate to the civil EDTO, but meet the intent (eg P-8 designed to conduct long range over water operations).
10.11 Design Requirement (Essential). Where the MAO has determined that a Defence aircraft having more than two engines is subject to DLRO management, the aircraft design must be evaluated against the requirements defined in ICAO Doc 10085 Extended Diversion Time Operations (EDTO) Manual for aircraft having more than two engines.
10.12 The airworthiness design requirements for EDTO defined by the ICAO in ICAO Doc 10085 provide an appropriate benchmark against which to establish the level of safety for DLRO afforded by Defence aircraft having more than two engines. Per the ICAO requirements, the following is applicable to DLRO for Defence aircraft having more than two engines:
The type certification standards and system of maintenance defined for the aircraft type in the applicable Authority recognised airworthiness code (refer Section 1 Chapter 3) are suitable for DLRO. There is no requirement for additional DLRO specific compliance demonstration, establishment of a maintenance program or performance/reliability monitoring program (eg engine performance monitoring) other than those programs already identified and implemented for ‘normal’ aircraft initial/continuing airworthiness and operations.
A review of time limited systems (TLS) is required to confirm that the aircraft has the capability to safely divert to a suitable airfield at all times during DLRO, with any TLS limitations being published in aircraft documentation (eg MMEL/MEL and AFM) where required. This review should include DLRO significant systems, to identify the system having the most time-limiting impact and inform the decision on maximum diversion times permitted under the DLRO approval. The outcomes of this assessment, must be communicated to the MAO to support informed risk based decisions on the aircraft's suitability for conducting DLRO.
10.13 Where a change is proposed to an existing DLRO approval, such as an extension to the approved diversion time, the technical basis upon which the DLRO approval was granted may be invalidated. Therefore, to support ongoing validity of the DLRO approval, proposed changes to the extant approval must be evaluated and verified to not impact the technical basis for DLRO, or the MAO must be advised of any change to the risks communicated via the original DLRO assessment.
10.14 Design Requirement (Essential). Where an existing DLRO approval is to be extended/ amended, the impact of the proposed changes on the DLRO technical assessment must be evaluated and the MAO must be advised of any impact on associated risks.
10.15 Design changes to Defence aircraft may undermine the basis upon which the original DLRO approval was granted, resulting in additional hazards and associated risks. Where a design change impacts the suitability of the design for conducting DLRO, the basis upon which the technical recommendation for DLRO was made must be reassessed. The assessment must consider the impact of proposed changes, particularly for DLRO significant systems or continuing airworthiness arrangements. Where the assessment identifies a change in the risk profile associated with DLRO, the outcomes of the assessment must be communicated to the MAO, together with recommended risk treatment, to inform the decision on continued DLRO approval.
10.16 Design Requirement (Essential). Changes to the type design that may impact the suitability of the Defence aircraft to conduct DLRO must be evaluated and confirmed to have no impact on the basis for DLRO approval, or any identified impacts must be communicated to the MAO.
10.17 As previously highlighted, DLRO maintenance and reliability requirements for Defence aircraft having more than two engines are satisfied through compliance with the applicable Authority recognised airworthiness code (eg FAA FAR Part 25 and Part 33, EASA CS-25 and CS- 33, MIL-HDBK-516C, DEF STAN 00-970). Consequently, for Defence aircraft having more than two engines, no DLRO specific maintenance or reliability programs are required in addition to those implemented for ‘normal’ aircraft continuing airworthiness and operations.
10.18 Continuing airworthiness programs provide a substantial contribution to reducing risks in civil EDTO. Similarly, maintenance and performance monitoring programs adapted to account for additional hazards posed by DLRO enhance the level of safety for Defence two engine aircraft. Further, since they are principally extensions to existing maintenance and performance monitoring programs, DLRO specific programs are likely to be reasonably practicable to implement. The system of maintenance and the performance monitoring and reporting systems in EDTO standards provide a reasonable benchmark for similar requirements in the DLRO context for two engine Defence aircraft. Therefore, the following DLRO continuing airworthiness requirement, based on the civil EDTO requirements, is prescribed by the Authority.
10.19 Design Requirement (Essential). Where a two engine Defence aircraft is subject to DLRO management, a DLRO system of maintenance, and performance monitoring and reporting systems, must be defined to satisfy the requirements of:
CASA CAAP 82-1 – Extended Diversion Time Operations, or
FAR Part 25 Appendix K – Extended Operations, in conjunction with FAA AC 120-42B – Extended Operations, or
EASA AMC 20-6 – Extended Range Operation with Two-Engine Aeroplanes ETOPS Certification and Operation.
10.20 Where the proposed DLRO system of maintenance and/or the performance monitoring program for a Defence aircraft does not satisfy the requirements of the civil EDTO standards, the Authority is to be petitioned for a determination on the adequacy of the proposed programs.
10.21 Further guidance on implementing the DLRO design and continuing airworthiness requirements prescribed in this chapter can be provided by the chapter sponsor.