*3.8. Upgrade*

Upgrades are common for military aircraft, including airlifts. Avionics' and cockpit modernisation programmes, both for operational and technical reasons (some of them related to tackling obsolescence and reliability issues), are popular among operators. These kinds of programmes add value to older fleets by enhancing operational capabilities and/or extending service life. The Lockheed Martin C-130 serves as a good example, with the Hellenic Air Force C-130H and -B fleet avionics upgrade programme (AUP) in 2002 offering an indication in the costs involved—a 15 aircraft fleet upgrade at a cost of \$6 million per aircraft [5].

These cost-raising factors are commonly observed in combination, especially in older fleets. The case of the Lockheed Martin C-130's structural integrity offers a good example. This aircraft type has served many defence forces around the world over the past fifty years, as well as civil operators offering contracted services to state organisations (a popular choice when cost-saving or exposure to risk is sought by the states). The entering of the Lockheed Martin C-130 into civil registers has placed the type under the scrutiny of civil aviation regulators, such as the Federal Aviation Authority (FAA) in the United States (US) and the European Aviation Safety Agency (EASA) in Europe. For example, a search in the EASA safety publications tool [6] reveals a number of primary structure-related Airworthiness Directives (ADs) for the Lockheed Martin C-130 (Model 382). These EASA ADs are linked with previously issued FAA ADs, which offer further details on the type and the estimated cost for major structural repairs and inspections required for the aircraft wings (i.e., center wing box, CWB, and outer wing). One can observe the significant labour and part replacement costs involved in complying with these ADs (i.e., the CWB replacement cost is estimated at \$5 million and that of the outer wing at \$8 million, both per aircraft) [7]. It is interesting to note that the newer C-130J model is required to undertake similar maintenance tasks to ensure the integrity of the wing structure. For example, in 2017, the Royal Air Force (RAF) decided to retain as operational 14 of their C-130Js until 2035. For this, it was required to replace the aircraft CWBs, at a total cost of \$143 million [8]. This offers a flavour of the costs associated with legacy structural designs, heavy operational utilisation and the effect of heavy maintenance on the sustainment and affordability of older airlift types and fleets.

### **4. New Airlifter Technical Considerations**

Assessing the long-term maintenance and sustainment costs of airlifters, i.e., 20, 25 or even 30 years from today, is important. There are various sources that can be used to inform the technical decision-makers, including the manufacturers, which can offer insight on the utilisation costs and publicly available research/industry reports, in conjunction with cost analysis and prediction models, i.e., [9]. For example, a report published by the RAND Corporation in 2013 provides, among others, a comprehensive analysis of the sustainment costs of US fleets of Lockheed Martin C-130 [10].

A "mix and match" strategy is especially important for small and diverse fleets, since these are more challenging and less cost-inefficient to run in comparison to more substantial size fleets. Any new aircraft type, including airlifters (given the much higher investment involved), should be evaluated

against the existing technical support infrastructure, technical capability and fleet mix of the operator. An exercise evaluating different candidate airlift types can be very useful in this regard.

Developing and maintaining in-house technical support (and engineering) capability is essential not only for self-reliance purposes but also can be beneficial for sustainment cost-saving purposes. Efficient technical solutions, contributing to lower sustainment cost, can be sourced from defence engineers and technicians, and experience has shown that this can yield positive results for the operators. For example, aircraft fatigue monitoring programmes and inspection repair solutions are typically high-cost and value engineering capabilities. Moreover, the operator can interact in a more productive way with the aircraft manufacturer and external technical services' providers.

Learning from other users can be useful when evaluating new aircraft types. Experience of airlift users, especially for widely used types and models, offers valuable information on technical support matters. The sharing and exchange of technical information, data and findings, as well as practices that can have an effect on maintenance and sustainment, constitutes good practice for technical and engineering support purposes. This collective approach can also work for the benefit of operators when negotiating technical solutions with the aircraft manufacturer.

Dual certification and the airworthiness managemen<sup>t</sup> framework can contribute (positively or negatively) indirectly to the maintenance and sustainment cost. This is related to the compliance requirements, since tailoring the certification standards (i.e., when an operator wishes to comply with non-typical requirements contained in widely used airworthiness codes) can increase the end-product cost. The European Military Airworthiness Requirements (EMARs) [11] were developed to bridge the gap between military-customised and civil certification requirements by adopting a common regulatory framework across different defence forces. Combining civil aviation regulatory structures and practice (where cost is an important element) with defence specific airworthiness requirements may offer to military operators the best of both worlds. In the case of airlifters, defence forces selecting dual-certified aircraft types have the opportunity to utilise these efficiently should such a hybrid airworthiness system be implemented. However, an operator can still operate dual-certified aircraft types, but it may be generally more onerous to manage technical support and ensure regulatory compliance when having to rely on bespoke contracts.

One option which military operators can also consider is civil-derivative or civil-certified airlifters. These aircraft types can be maintained under a civil or civil-based airworthiness framework. These aircraft can undergo maintenance and can be certified in EASA (or FAA) Part 145 aircraft maintenance organisations. This would offer cost benefits for the military operator and the defence and the civil aviation industry. In-country civil aircraft maintenance organisations would be able to offer their services to the defence force, expanding their business in the military aircraft maintenance sector. The same approach would also apply for the supply sector (spare parts and consumables), which can be sourced from a wider (non-defence specific) network/range of sources. Overall, this can have a positive effect on the sustainment cost of such (civil-derivative/civil-certified) airlifters.

The four pillars of technical support described in Figure 1 (supply, restoration and upgrade, engineering and regulatory compliance) can serve as a guide for identifying the technical considerations applicable to airlifters when evaluating the acquisition of new or used aircraft. These technical considerations have been mapped against the four pillars of technical support, presented in Figure 3 in a summarised way.


**Figure 3.** Technical considerations for the evaluation of airlifters and mapping against the four pillars of technical support described in Figure 1.
