At the end of this month the US Navy will begin a 10-year programme to replace its 250 Lockheed Martin P-3C Orion maritime patrol aircraft (MPA) and EP-3E Aries II electronic intelligence platforms with a new Multi-Mission Maritime Aircraft (MMA).

The USN has budgeted the relatively small sum of $3 billion for development and as a result is counting on industry to come up with innovative airframe and mission system solutions.

MMA is modelled closely on the Joint Strike Fighter (JSF) competition, with the principal emphases on cost rather than performance at any price. Furthermore, the USN has not formalised its requirements, but instead elected to evolve an operational requirements document (ORD) with industry over the next 18 months as part of a two-phase component advanced development (CAD) effort. The aim is keep requirements and cost growth in check, while working to reduce risk. The Naval Air Systems Command (Navair) is expected to award CAD contracts to BAE Systems, Boeing and Lockheed Martin by the end of this month. At the same time it will release the third initial requirements document (IRD III) to provide a broad outline requirement as they explore multiple options during the six-month initial CAD phase. This will be followed by a "rolling downselect" of proposals as CAD moves into the planned 12-month phase two, for which $50 million has been earmarked.

"We're trying to encourage companies to take risks and we've said we will entertain multiple concepts or proposals. The validation criteria will be determined during that first six-month period, based on maturing requirements and affordability among other things. We will then take forward the most promising concepts into Phase 2," says Capt Al Easterling, USN MMA team lead. Phase 2 is to conclude by early 2004. By then the ORD will have been finalised and bids submitted for system development and demonstration (SDD).

Limited development money dictates that the USN must look for a derivative of an existing commercial or military airframe rather than an all-new platform. The aircraft will be required to fulfil two basic missions - surface attack and surveillance. Accordingly, Boeing is looking at a militarised Next Generation 737 and BAE at the improved Nimrod MRA4. Lockheed Martin has opted for a new-build and improved Orion 21 version of the P-3 turboprop, having at the last minute scrapped plans to team with EADS to offer the Airbus A320.

For Boeing the choice is between the 737-700 Increased Growth Weight (IGW) or larger -800. "If we went with an -800 variant, that would give us a few more options," says Jack Zerr, Boeing MMA programme manager. "It's longer and can accommodate a bomb bay aft, which gives us a few enhancing characteristics. There are a number of things our electronic people want to sling under the aircraft and if we move the bomb bay, we can add antennas and operators forward."

UK interest

BAE had said it would not enter CAD without first enlisting a US partner to produce the Nimrod MRA4 locally, but instead looks set to compete on its own, at least during Phase 1. It will not be easy, acknowledges Tom Nicholson, BAE managing director Nimrod. "Technically we could go it alone, but it would be difficult as we would have to convince the navy that we are not a start-up organisation. BAE has to be part of a credible consortium…we're recognised as a black box maker at the moment," he adds.

Lockheed Martin, having decided to stick with the established P-3 airframe, plans multiple trade studies during Phase I to determine what improvements it will make to the propulsion and avionics systems. The company is considering either the Rolls-Royce AE2100 or Pratt & Canada Canada PWC150 turboprops, and a two-man glass cockpit with a digital architecture similar to that of the Lockheed Martin C-130J and planned for the C-5 avionics modernisation. Supplier selections will be made during Phase 2, says Ray Burick, Lockheed Martin MMA programme manager.

None of the bidders would appear to offer straightforward solutions. Militarising the 737 is unlikely to be easy and Boeing already faces some of the issues that Hawker Siddeley did in the mid-1960s when transforming the Comet into the Nimrod MR1, such as adding an internal weapons bay. The Nimrod MRA4 represents a much improved system, but the airframe has been out of production for 30 years. The P-3 has an equally long heritage that goes back to the L-188 Electra.

MMA has rekindled the turbofan- versus turboprop-powered aircraft debate for the maritime patrol mission. Lockheed Martin has long contended that the four-turboprop P-3 is superior for low-level missions, such as dispensing and monitoring sonobuoys, as well having longer endurance. Boeing counters that this is more than compensated for by the 737's approximately 100kt (185km/h) faster transit speed, which it claims knocks 2h off a typical 12h mission over a 2,800km (1,500nm) radius without any reduction in the time on station.

"Back in the days of turbojets they couldn't compete at low level, where a P-3 has to operate occasionally. With modern turbofans and high bypass ratios, our analysis…says we can do fine in the low-level environment. We're not going to do exactly as well as existing P-3s, but we do well enough that we don't suffer that much at low altitude. We can then take advantage of a much higher altitude capability that comes with a jet," says Zerr.

The IRD so far has been deliberately ambiguous about the new systems to be accommodated by the MMA. Instead, Navair is looking to industry to judge how many current P-3 systems could be integrated into the new aircraft's open-system architecture and what is available off-the-shelf. Initial SDD funding does not allow for the development of a new radar, acoustic processor or hyperspectral imaging for mine warfare. The intention is to provide the capacity for "plug-and-play" additions and block upgrades.

Latest avionics

For the initial Block 1 MMA, Easterling says: "We're using performance-based specifications and telling industry: here's what the latest version of the P-3's AIP [avionics improvement programme] will do, and here's the latest J mod on the EP-3. You must provide a performance that is no less than these systems. If industry can provide a greater capability within the affordability target, we'll embrace that."

Among the limited number of MMA key performance parameters that have been defined is the need for interoperability with unmanned air vehicles (UAV) such as the Northrop Grumman RQ-4A Global Hawk. Large UAVs were an option examined during earlier analyses of alternatives and they are seen as an adjunct to manned platforms. Navair accordingly is asking that any future MMA should be able to take control of a UAV's sensors and ultimately, through spiral development, airborne control of a vehicle.

The USN plans to award a development contract during the first quarter of 2004, with the goal for MMA to reach an initial operational capability between 2010 and 2012. In the absence of a structural life extension programme (SLEP) of the current P-3 fleet there is no room for delay - Lockheed Martin estimates that around 100 P-3/EP-3s will have exhausted their fatigue lives within 10 years. But many question whether the navy can afford the MMA, with an acquisition bow wave already threatening to swamp the defence budget in 2007-09.

Given that the projected cost of a SLEP for the P-3/EP-3 fleet is close to that estimated for MMA development, combined with the USN's plan to retire its only other fixed-wing MPA asset, the carrier-based Lockheed S-3 Viking, Easterling contends that the "navy can't afford not to pay for it". One suggestion is to adopt a JSF-type approach and open the programme to international participation.

Australia has expressed interest in the MMA as a possible AP-3C replacement and has seconded an official to the programme office. Japan has said it intends to pursue an indigenous P-X successor to its Kawasaki-built P-3Cs, but is looking to collaborate on mission systems. Germany and Italy have similar joint requirement to replace their Dassault Atlantics, while the Netherlands and Norway have expressed interest. "I think international MMA collaboration is likely in some form," says Easterling.

Source: Flight International