Sustainment: Sense and sensibility - sustaining the Seahawks | ADM Sept 2009

But is caution prevailing over good sense where hi-tech solutions are proposed?

Tom Muir | Canberra

Back in the early 1980s, the RAN selected Seahawk for its Role Adaptable Weapon System (RAWS) and acquired 16 S-70B-2s, which featured an S-70B airframe and RAN-specified avionics.

These were substantially different from the US Navy version and included the MEL Super Searcher X-band radar (capable of tracking 32 surface targets), CAE Electronics AN/AQS-504 internally-mounted MAD system, AN/SSQ-81 Barra sonobuoys and Rockwell Collins advanced integrated avionics.

These include cockpit controls and displays, navigation receivers, communications radios, airborne target handoff datalink and the tactical data system.

Eight S-70B-2s, ordered in 1984, were supplied directly by Sikorsky and eight more, ordered later, were supplied as kits for assembly by ASTA in Australia.

The first major update came with SEA 1405 Phases 1 and 2, contracted in 1998, with modification of the fleet beginning in April 2005 and finally completed earlier this year for all 16 aircraft.

The upgrade included the Raytheon AAQ-27 FLIR system, Elisra AES-210 ESM and radar warning receiver, Northrop Grumman AAR-54 MAWS and BAE Systems ALE-47 CMDS.

The project required major modifications to the airframe to incorporate the new systems' sensors and electronics equipment.

These include a FLIR turret in the aircraft's nose, MAWS sensors in fuselage quadrants, installation of the ESM antennas/receivers and the tailboom positioning of the CMDS.

Other modifications were required for the DF antennas, avionics bay equipment and the console and instrument panel installations.

As one might expect the program slipped due to integration challenges - and interestingly at one stage these included holding off for the now defunct Super Seasprite program to complete work on related development, which did not eventuate.

This activity focussed on providing the Seahawks with enhanced surveillance capabilities and improved self-protection measures.

These might have been seen as important steps towards endowing the aircraft with multi-mission capabilities instead of its current ASW systems configuration.

The next major support activity planned was the Seahawk midlife upgrade (AIR 9000 Ph 3) which was to address aircraft capabilities, through life support costs, operational availability, commonality and life of type issues.

At the time it was believed that the processing power of aircraft's mission system would be a major focus of the mid-life upgrade, since the original system - the one that took six years to bring up to full functionality - was incapable of supporting new, associated systems such as enhanced acoustic capabilities, a new radar, the integration of advanced weapon systems such as the Penguin Mk2 anti-ship missile (then purchased for the Seasprites) and/or Hellfire, together with the MU90 lightweight torpedo.

As Phase 3 has morphed into the AIR 9000 Seahawk Capability Assurance Program (SCAP 1 and 2), the project has been reined in and is now focused on maximising the number of aircraft available for operations by undertaking a lower risk program that only addresses obsolescence without capability enhancements.

Anti-ship missiles and lightweight torpedoes are no longer in the frame.

SCAP 1 is to address immediate obsolescence issues including the Tactical Display Units, Engine Control Units, the Automatic Flight Control System, the Identification Friend or Foe (IFF) system and the Mission System Simulator.

SCAP 1 received first pass approval late last year.

SCAP 2 addresses aircraft obsolescence beyond the scope of SCAP 1 until the aircraft's withdrawal from service and is primarily concerned with resolving obsolescence in the Seahawk's main mission computer, the Display Generator Unit (DGU).

Under the DMO's 2009/2010 annual procurement plan the possible replacement of the DGU was to be initiated with the release to industry of an ITR in July 2009.

Earlier, an RFQ was released seeking an avionics systems specialist to carry out risk reduction activities to enable First/Second pass project approval for SCAP 2.

The task focussed on the development of DGU function and performance specifications (FPS) as a preliminary to the release of the ITR.

SCAP 2 will also see the possible replacement of the Seahawk's internal communications with price and availability data sought before February 2010.

The estimated savings through replacing AIR 9000 Phase 3 with SCAP 1 and 2 are considerable.

The individual cost of each SCAP phase is projected by the new Defence Capability Plan (DCP) to lie in the $100-$300 million range - a far cry from the projected $750-$1 billion for the original midlife upgrade that was seen in the previous iteration of the DCP.

DGU - replace or emulate?
SCAP 2 is responsible for resolving DGU obsolescence in the S-70B-2 Seahawk helicopter and function and performance specifications are being developed for a replacement DGU.

Another part of the task is the development of a test concept document for the system.

While previous official references to managing DGU obsolescence have usually referred to the system's possible replacement, it now seems that the focus of SCAP 2 is on replacing the system and ignoring DSTO's work on re-lifing the Seahawk DGU through the application of emulation technology.

We could be wrong - perhaps DSTO's virtualisation concepts, aimed at enabling the legacy DGU to behave as a modern system may be proposed for first pass consideration as one option.

The other option is a business case for a replacement system.

Emulation refers to the process of mimicking, in software, a piece of hardware or software so that other processes think the original equipment/function is still available in its original form.

Emulation is essentially a way of preserving the functionality of, and access to, digital information which might otherwise be lost, due to technological obsolescence.

And the arguments for emulating, rather than replacing the Seahawk DGU are compelling.

In his paper on Virtualisation, presented as part of a DSTO team presentation on Advanced Technologies for Legacy Mission Systems, at the Ageing Aircraft Forum in 2007, ADM has taken the liberty of rephrasing presenter Mark Davies' comments in support of virtualisation.

Dr Davies describes a hypothetical issue where the software works fine, but the hardware is unsupportable.

The system is not quick enough, needs more software to handle increased data but doesn't support new interfaces.

There are supportability issues with the development environment and the system's compiler is no longer supported.

Hardware is no longer supportable and there are inadequate facilities to deal with debugging of both software and hardware.

He then points to the drawbacks of buying an all new system including issues of risk, time, cost, certification, the re-hosting of existing software, the rewriting all the inputs/outputs (I/O) for the new hardware, a new development environment including compiler compatibility and finally the necessary re-certification of all the code.

On the other hand, through the incorporation of virtualisation hardware, using programmable (FPGA) devices and customised integrated circuits, the system now presents as a faster version of the old CPU.

New I/O cards and new drivers will be required, but the same compiler can be used and the original development environment remains.

He says the desirable features of virtualisation include low technology risk, a form fit and function solution, and the original code can be run virtually unmodified.

It is also cheap and fast to implement, and provides a new development suite.

New capability can be added as required, focussing on the new host at a high level, using a modern language.

DSTO's emulation techniques
DSTO sees emulation technology as promising to provide a means of addressing obsolescence issues in legacy computer processors in the military avionics domains.

There is also the suggestion that such technology might apply to safety critical and safety related systems in these domains.

Back in 2002, DSTO announced that it had developed an experimental computer emulator which, able to emulate a range of airborne mission computer types, had the potential to replace ageing ADF computer equipment.

The system was run through proof-of-concept testing on the F-111 simulator at RAAF Amberley.

The emulator used TRW's (later Northrop Grumman's) RePLACE (Reconfigurable Processor For Legacy Avionics Code Execution) software and was being investigated for its potential to replace many ageing airborne mission computers in the ADF under task sponsorship by the Director General Aerospace Development (DGAD).

The technology used commercial off the shelf components including a fast, modern processor and providing backward compatibility for existing legacy software.

Subsequently DSTO developed a concept demonstrator, utilising the same RePLACE emulation technology for the
Seahawk DGU.

To assess how the Directorate General Technical Airworthiness (DGTA) might accept emulation technology, DGTA then evaluated the technology and specifically RePLACE in the context of the Seahawk DGU.

The evaluation considered the emulation architecture, including identification of risks largely unique to the technology, as well as application of ADF preferred avionics software assurance and software safety standards to this technology.

Evaluation of emulation technology, through exploration of emulation architectures and RePLACE as a case study,
has allowed DGTA to define certification and regulatory guidance for the development of emulation technology within the ADF context.

Does this mean a relatively clear path to certification for an emulated version of the Seahawk DGU is now on the cards, as opposed to the onerous and lengthy procedure involved in certifying a replacement DGU?

* Antonio DiPietro, Robert O'Dowd, Mark Davies: Advanced Technologies for Legacy Mission Systems, a team presentation by Air Operations Division, DSTO at the Ageing Aircraft Forum, 23-25 May 2007.