It has proved so difficult and expensive to upgrade the F-22 Raptor, whose stealthy body contains sensors and electronic brains, that the U.S. Air Force may take the unprecedented step of threading what amounts to a second central nervous system into a fighter jet.
By introducing an open architecture to one of the world's most tightly knit proprietary systems, service officials hope to make it much cheaper and easier to insert new technology - even gear developed for the F-35 Lightning II - into the stealthy air-superiority fighter.
"This jet has a very highly integrated avionics system. Because of that tight coupling and that highly integrated nature, it makes it very difficult, and we are highly reliant upon [Raptor makers] Lockheed Martin and Boeing to do any kinds of modifications to the jet," said David Weber, deputy director of the F-22 System Program Office (SPO) at Wright-Patterson Air Force Base, Ohio.
Weber said the open-architecture effort is meant to allow the Air Force to open upgrade work to competition.
Today, he said, "the architecture is proprietary to Lockheed Martin, and we're kinda stuck with Lockheed Martin when we want to integrate something new."
Weber said the work is at such an early stage that the F-22 SPO has no guess how much it might cost.
This year, service officials plan to study the options, in part by issuing a request for information inviting contractors to suggest demonstration projects to help flesh out the alternatives.
"All of them have different ideas about how to go about doing this," Weber said.
In October through December, the service will award contracts to allow contractors to demonstrate ideas in a lab or flying testbed, said Col. John Williams, who runs the F-22 SPO's modernization office.
The SPO officials said Boeing and Lockheed would be welcome to bid on the demonstration contracts.
Lockheed, which had earlier proposed to essentially port the hardware and software architecture of the F-35 Lightning II into the Raptor, might respond to the Air Force solicitation with a similar proposal, said Jeff Babione, Lockheed's Raptor program manager. But Babione said the company might propose a different solution, depending on the service's requirements.
The Air Force will ultimately select one contractor to install the new architecture on its Raptors - ideally, said Weber, all 185 that will be built, less two losses.
"From our perspective, the fleet size is so small compared to where we wanted to be, our objective would be to make this applicable to all aircraft," he said.
The SPO deputy director said it may be deemed too costly to install the new architecture on the 34 oldest Raptors, which are currently used for training. Those planes are also not slated to get the Increment 3.2 upgrade, the next major group of hardware and software upgrades for the Raptor fleet.
But Weber noted that the new architecture might also make it cost-effective to bring those oldest Raptors up to the 3.2 standard.
If all goes well, development work could begin in earnest around 2014 as part of the development of Increment 3.2C, which is slated to begin installation in 2019 or 2020, he said.
As currently envisioned, the new network would be grafted onto the F-22's existing avionics, Weber said. The twin-engine jet's current network would continue to carry data between existing components, while upgraded ones would be linked by the new network. The data from both architectures would be translated and fused so that the jet continues to operate as a cohesive whole.
The installation of the new architecture might happen in one step, or it might proceed piece by piece, Williams said.
"Potentially, you could do it multiple times based on what you're trying to open up," he said. "You're opening up the [communication, navigation and identification]; maybe you're opening up the radar more, something like that. You may actually have multiple guys doing it, but it will be to a common standard."
As more systems are ported over to the new architecture, the older systems would wither away.
"Gradually, you'd have to start migrating some of the functions that we currently have in our core integrated processor away from the core integrated processor, so that everything doesn't flow through that piece," Williams said.
It may or may not be possible to migrate all of the Raptor's functionality.
"It depends on the degree we can open up the architecture," Weber said.
Lockheed's Babione said it might not be cost-effective to move everything to the new system.
The F-22 has received one upgrade - called Increment 2 - since it first arrived on Air Force flight lines in 2005. Those upgrades have added the capability to drop two 1,000-pound Joint Direct Attack Munitions to the aircraft.
A planned upgrade, called Increment 3.1 and slated to begin this year, will add synthetic aperture radar mapping, the capability to carry eight Small Diameter Bombs, and other features.
In 2014, a software-only upgrade called Increment 3.2A will add electronic protection against jamming, better Link 16 receive capability and combat identification, and other improvements. In 2017, Increment 3.2B will add support for the plane's AIM-9X short-range and AIM-120D medium-range anti-air missiles, among many other upgrades.
In 2008, then-Pentagon acquisition chief John Young put the total cost of developing and installing Increment 3.1 and what became 3.2A and 3.2B at around $8 billion. The figure has likely gone up because the Air Force now plans to upgrade more F-22s.
Once the new architecture is installed, "if we want a new capability on the airplane, we can go out to industry with an RfI [request for information] and say, 'You all got good ideas; can you make it work with this architecture?'" Weber said.
The ultimate goal is to allow systems such as new radars to be "plug-and-play," as a printer might be to a desktop computer, he said.
This might allow the Raptor to use technology developed for the F-35 Lightning II without time-consuming and expensive integration work, Williams said. Ë