Avionics designers get set to take the next step

Sept. 1, 1998
First it was integrated electronic architectures to replace groups of hard-wired boxes, and line-replaceable units were in vogue. Today, designers of advanced aircraft such as the Joint Strike Fighter prepare to move COTS into the mix of the most powerful avionics systems ever built

First it was integrated electronic architectures to replace groups of hard-wired boxes, and line-replaceable units were in vogue. Today, designers of advanced aircraft such as the Joint Strike Fighter prepare to move COTS into the mix of the most powerful avionics systems ever built

By J.R. Wilson

For decades, U.S. military leaders have sought not only to improve aircraft electronics capability, but also to control avionics procurement and logistics costs. In the early 1970s, for example, they approved production of the first U.S. combat aircraft with an avionics suite integrated on a serial data bus. This aircraft, the Boeing (nee McDonnell Douglas) F-15 Eagle air-superiority jet fighter, had the MIL-STD 1553 1-megabit-per-second data bus, rather than a hard-wired point-to-point - or "federated" - avionics architecture.

Later in the 1970s and `80s military officials became serious about using line replaceable units (LRUs) to reduce maintenance, depot repair, and parts storage costs on jet fighters, starting with the Boeing F/A-18 fighter-bomber. Then in the early 1990s, efforts on designs for the Lockheed Martin F-22 Raptor jet fighter and the Boeing-Sikorsky RAH-66 Comanche scout/attack helicopter represented the first attempts at using commercial off-the-shelf (COTS) avionics components common to different platforms.

Today, the Joint Strike Fighter (JSF) project - now a competition between Lockheed Martin Corp. and The Boeing Co. - is picking up where the F-22 and RAH-66 failed to meet many of those expectations, and is benefiting from nearly a decade of additional technology development. Also influencing JSF avionics is the effort to reduce military program costs by increasing the use COTS hardware and software, despite some concerns in government and industry that the pendulum has swung too far against military specifications (mil specs).

Driving the COTS effort - particularly on the JSF - is a growing emphasis on open architectures and on the ability to upgrade one part of a system without changing other elements. This is of special concern because it takes an average of 15 years for a new military aircraft to go from concept to production, then remain in service for as long as a half century - perhaps even longer.

Military leaders say COTS and rapid technology insertion is central to JSF planning. Since processing capability alone doubles about every two years, the systems designated in original JSF plans in 1990 would be eight generations out of date - and long out of production - by the time Lockheed Martin officials turn production aircraft over to the U.S. Navy, Air Force, Marine Corps, and U.K. Royal Air Force in 2006.

Despite the push for COTS, JSF avionics designers must carefully validate commercial-grade processors and systems, some of which were designed for a benign office environment, to meet the harsh operational requirements of Navy, Air Force, and Marine jet fighters. The need to withstand harsh military environments was the issue that most mil specs initially were designed to address, although the system grew into an unwieldy and largely bureaucratic nightmare that drove up costs and sometimes proved counterproductive in service.

There also is a growing design and manufacturing convergence in the newest generation of military and commercial aircraft. This convergence may involve processes, applications, and environmental requirements among the F-22, JSF, and F/A-18E/F combat jets, as well as the Boeing 777 and 717 jetliners, for example. Among military and commercial aircraft designers, the need to backfit old aircraft with the new cockpits and avionics systems developed for the latest generation has become a substantial business.

Joint Strike Fighter

U.S. Air Force Col. Bob Lyons, program manager for the Boeing JSF-X32 contender, has a unique perspective on the latest in military avionics. He previously headed the avionics integrated products team (IPT) on the F-22 program.

"The F-22 laid the architecture for the JSF," Lyons explains. "But technology has now moved almost a decade ahead and those things we didn`t get done on the F-22, we will on the JSF. Also, the F-22 was strongly autonomous and air-to-air oriented. With the JSF, we have extended our horizons to an aircraft with air-to-air and air-to-ground requirements. Secondly, we recognized that, unlike the old autonomous fighters, JSF is just one more part of the `system of systems`."

The F-22 program taught military officials a hard lesson in how quickly commercial technology development is accelerating. For the F-22, technology simply outpaced the program. Lyons says despite their best efforts to create a truly open architecture, "it just technically wasn`t possible to do, and [the defense] industry wasn`t ready for it."

The problems that hampered some avionics goals of the F-22 are even more acute for the JSF. "COTS hardware is so much faster than it used to be and if we buffer the hardware from the software through an open-system architecture, it doesn`t really matter what happens on the hardware side," he explains. "This time we think we have a set of chips that will be highly capable, buffered from the applications software, based on a very open commercial system architecture, and with a set of hardware components that can be replaced at any time."

Easy upgrades

A primary goal of the JSF avionics effort is to create a system in which the replacement of separate boxes or circuit boards has no adverse effect on the rest of the avionics suite, says U.S. Navy Cmdr. Dave Wooten, deputy lead on JSF avionics. That way, technicians must validate only the replacement parts, rather than the entire avionics system, after upgrading certain components. "By reducing the amount of regression testing associated with it, you actually speed up your insertion process, which allows you to take greater advantage of commercial technology improvements," he says.

This new approach does not mean all legacy components are necessarily doomed to the trash heap. For example, Lyons says the light and inexpensive 1553 data buses probably will remain in the JSF architecture, although designers may need fiber optics connectors for high data throughput requirements. The key, he points out, is to avoid making something overly complex simply because technology allows it.

"The interface is the key to the program," Wooten adds. "The degree and rate compression algorithms will dictate what kind of interface you have. We don`t` want to drive to any one specifically. By leaving it up to industry to choose, we allow them to find the best method."

With JSF, government officials have mandated not a single military specification. Yet on more than one occasion, industry designers have sought to fall back on a mil spec themselves, Lyons says - something the program office then tries to talk them out of using, even though many mil specs were considered necessary to keep military aircraft flying and their crews safe.

"Our experience has been that commercial electronics have far surpassed what we had written down in military standards," he says. "But we do need a guide spec that says this is a military environment and commercial practices must work in a military environment."

Also of growing importance is the need to standardize avionics components across platforms, across services, among allied nations, and even with the commercial world. Toward that end, Lyons predicts an eventual melding of military and commercial standards.

The increased reliance on LRUs and modular components also has led Air Force planners to consider eliminating on-site storage and depot repair on many future avionics components. Instead, technicians would either throw away a bad part or ship it back to the original manufacturer for overnight replacement.

Such a system would be difficult for the Navy and for Navy suppliers, however. Delivering parts to aircraft carriers deployed at sea often takes more than one day even under the best of circumstances. Yet to the extent such just-in-time supplies and non on-site repair could be established, however, it could reduce the storage requirements for parts and the numbers and training requirements of maintenance personnel.

In the case of JSF, Boeing and Lockheed Martin leaders are looking at ways to create a long-lived, low cost supportability plan, which may include manufacturer handling of upgrades and repairs rather than doing everything at the depot level. Both companies currently are developing JSF prototypes for a flyoff that will lead to the ultimate selection of a single aircraft and manufacturer in 2001, with full production anticipated sometime after 2005. But the joint program office has left open the option of requiring the winner to incorporate some elements of the losing design that may be considered superior to those of the chosen aircraft.

Commercial to military and back again

With the increasing emphasis on COTS, the commercial world has become the lead innovator in technologies and processes. Commercial suppliers also are benefiting from a new concept of government-off-the-shelf (GOTS) to stockpile a sufficient quantity of obsolescing items that cannot be easily upgraded but are going out of production These approaches are especially true of the two newest Boeing jetliners, the 777 and the 717.

"This is changing the avionics industry a bit because the companies that are integrating avionics are more strongly positioned for the future," says Gary Kirchoff, director of business development for TRW Avionics Systems Division in San Diego. "Those companies are predominantly Raytheon, Lockheed Sanders, Honeywell, and TRW. We`re all looking to try to be in a preeminent supplier position in a market niche, which is how companies are surviving these days."

TRW`s core competency niche involves aircraft communications, identification, and navigation, while Sanders, a Lockheed Martin company in Nashua, N.H., is concentrating on integrated electronic warfare. Meanwhile, Raytheon Hughes Systems in El Segundo, Calif., concentrates on processing and radar, while the Honeywell Air Transport Systems division in Phoenix focuses on finding new markets for the integrated electronics it developed commercially for the Boeing 777.

"Parts obsolescence is a continuing issue for all suppliers. Even in our EMD (engineering and manufacturing development) phase, we`ve had to propose product improvement programs that address diminishing manufacturing sources of parts that have become obsolete," Kirchoff says. "Aircraft stick around for 40 years and technology is changing rapidly. So you want to have an open- system design that allows you to change parts without having a dramatic impact on the overall system performance.

"We`re trying to drive as much commonality as we possibly can with all three programs - Comanche will be in production at the same time as JSF and F-22, so you want to have as much commonality as possible to reduce production costs," Kirchoff says. "That also is one way to try to leverage your market position for the future."

About 95 percent of TRW`s current avionics work is military. In the next five years, Kirchoff says, TRW leaders hope to see the commercial side grow to 30 percent. "The best approach is to work with another company already in the business to try to leverage (both areas of expertise)," he says. "Five to ten years from now, you`re going to see the military and commercial avionics markets overlap, with some merging of requirements. The whole landscape still has not been drawn in avionics. There is still an overabundance of facilities and capitalization versus market requirements that will drive further consolidation at the GEC, TRW, and Honeywell level in the next year or two. We`re really strategically positioned to double our division in the next five years, but on a global level, there`s probably still too much capacity."

Software solution

As the fastest avionics technology changes come in computers, military officials face major software rewrites, with attending high costs and potential risk. One proposed solution translates old software code for the new computers.

TRW engineers are offering their new Reconfigurable Processor of Legacy Avionics Code Execution, which they call "RePLACE." This software package enables military technicians to replace obsolete avionics computers with COTS-based systems. It also enables them to continue using existing binary-executable software without modification, and to upgrade the software to meet new mission requirements easily and affordably, says Doug Haldeman, business development manager at the TRW Avionics Systems Division Dayton Avionics Engineering Center in Dayton, Ohio.

RePLACE, which entered the market earlier this year, is not COTS; it requires some non-recurring modifications to deal properly with each LRU to be upgraded. Haldeman compares it to a computer`s operating system - once installed, other programs run on top of it.

RePLACE enables state-of-the-art COTS processors such as the Motorola PowerPC to emulate old military processors such as the 16-bit MIL-STD 1750A, Haldeman explains. To demonstrate RePLACE, TRW specialists ran side-by-side a program written for the 1750A processor that operates the F-16 jet fighter head-up display, and a program running C++ code written for the 32-bit PowerPC microprocessor.

"We`re concentrating on 16-bit legacy machines (primarily 1750A and the Z8002 architectures)," Haldeman explains. "The slower they get back in the distant past, the easier they become to emulate, primarily on 32-bit native machines. We also are looking at emulating some 32-bit machines, such as the [Motorola] 68040 and [Intel] i960, using a PowerPC - probably the 700 series - but that`s on the drawing board right now."

TRW officials say they expect a strong commercial market for RePLACE, especially if airline navigation moves to "free flight" in the near future (see sidebar). Free flight seeks to use new technologies related to the Global Positioning System, avionics, and communications to enable pilots to choose the most economical, fastest, or most direct route. Although free flight requires hardware and software changes, TRW officials say their package is one way to ease those costs. Company leaders also acknowledge that RePLACE is not a universal cure-all, and in some cases it may actually be cheaper to rewrite the software.

Plastic avionics packaging

The turn to COTS has raised some concern about the suitability of plastic-packaged components in avionics rather than more-expensive mil-spec ceramic parts. It is not difficult to find those in industry arguing both sides of the issue. "There have been a lot of success stories about commercial utilization of parts," says Wooten at the JSF office. "The GPS program, for example, has gone to a lot of plastic parts that initially engineers in the military looked askance on when they were proposed. But as long as they prove themselves in testing, these parts have reduced costs and reduced mean time between critical failures. So they have met all the stringent requirements. In the long run, I see a melding of the two standards."

The F-22 may be a trendsetter on that score, as its designers use more plastic parts than they did on the aircraft`s predecessors. Yet F-22 designers also are incorporating ceramics, and are qualifying ceramic and plastic parts to the military environment.

The problem for the Pentagon is not how to put evolving technologies into old platforms, but how to ensure the kind of reliability that has enabled them to keep those aircraft flying for decades, says Jim Martin, military systems consultant to National Semiconductor`s Military Aerospace Division in Santa Clara, Calif. Sometimes, he adds, the cost-savings of plastic may not be the best choice.

"There is a lot of talk out in the industry that everything has to be plastic, but that isn`t necessarily true from the DOD standpoint. There is a major drawback in plastic in a naval system, for example," he says.

COTS vs. mil-spec

The initial thrust of COTS was to broaden the technology to which the military has access, and to reduce costs. Martin, however, maintains the reliability of commercial parts versus military parts has been overstated. For example, he cites the longstanding military prohibition against rework at the wafer level versus a commercial world in which such rework is accepted. The end result of the commercial approach may be perfectly reliable in an air-conditioned office, he argues, but raises questions of risk if going into the engine nacelle of a jet fighter.

"A lot of program managers in the military are beginning to get concerned that what they put into their systems meets the environmental requirements," Martin says. "One solution has been to upgrade commercial-level components to military use, but IC providers as a group won`t support their components outside the original specs. And there is no way they can control or predict product shifts over time, especially if they occur outside the range the manufacturer has established. So that is a bad solution.

Martin claims that many people misunderstood the intent of former Defense Secretary William Perry when he laid out the Pentagon`s COTS strategy four years ago. "He says we need to make better use of commercial processes - he never says products, and that we need to get rid of mil specs that don`t contribute to the end product," Martin says. "There are a lot of mil specs that do contribute to the end product. One of the myths that arose early on in COTS was we didn`t need mil spec because we could rely on established commercial standards, but in fact, there are none. Controls over wafer fab, for example, vary widely from company to company."

More such problems are likely to arise, given the speed with which technology is advancing versus the continued long program development, production, and lifecycle times of military aircraft.

"You can`t take 10 years to go from concept to low-rate initial production and expect the parts list to remain intact," Martin says. "That process must be shrunk down. DOD does a great job talking to systems suppliers and a reasonable job talking to the second tier, but everybody gets isolated from the component suppliers. And because IC technology has become the critical linchpin of everything that gets done, that isolation can`t continue."

Another problem is the reliability - from a mil spec viewpoint - of new processes and products that may be so complex that the manufacturers themselves have a hard time testing and maintaining them properly.

"As a generalization, military designers are somewhat conservative, which hurts them in some ways," notes Larry Dano, a National Semiconductor military and aerospace communications engineer. "We know, for example, there have been some 20-year-old parts designed into the F-22. It would help reduce obsolescence problems if they would not do so much design reuse to reduce upfront costs, without figuring in the obsolescence costs."

Software-driven upgrades

Overall, industry leaders say the military has not yet caught up with the civil world`s rapid movement toward software-driven upgrades.

"This is a continually changing, evolving market area. At present, every time there is a change, they have to rip out old equipment and replace it, which is extremely expensive," says Cole Hedden, emerging markets segment leader for Honeywell Defense Avionics Systems in Albuquerque, N.M. "But if they can go to a software solution - especially one developed and paid for by the commercial arena - it will save a great deal of time and money.

"Near-term, we are seeing a clear shift to commercial hardware solutions," Hedden continues. "Far term, although it is a big challenge, the next step is changing to assimilate commercial software changes without significant modifications."

COTS does have its downside, especially when it comes to software. "There also is something I would classify as `dangerous COTS` - like software that you don`t know what the heritage is or if anyone is standing behind it," warns Doc Dougherty, director of technology at Raytheon Systems Co. in Arlington, Va. "There is a level of complexity where system configuration management overwhelms the benefits of off-the-shelf purchases."

Another concern is the shelf life of components, which in today`s electronics environment can be quite short. And the more designers incorporate COTS elements into a system, the more frequently they will need to make a replacement decision.

"Exactly how the military is going to react to an environment where they`ve demanded COTS without understanding how the market operates is not known," Dougherty says. "The integrator has no choice, because the commercial guy isn`t going to hold something on the market because the government might want a couple of them ten years from now."

Commercial avionics upgrades

Upgrading older aircraft to take advantage of new technology is not restricted to the military. For example, leaders of Federal Express Corp. (FedEx) in Memphis, Tenn., are refitting a sizeable fleet of converted DC-10 cargo jets with the two-man cockpit designed for the MD-11, which FedEx officials also have in their freighter fleet. The newly reconfigured aircraft, which also will incorporate elements from other new Boeing programs, are being re-certified as MD-10s.

FedEx officials are contracting with Honeywell Air Transport Systems in Phoenix to overhaul the avionics of 70 DC-10s, and an option for another 50, many coming out of commercial passenger use and being converted to freighters, says Jeanne Perillo, the MD-10 program manager for Honeywell Air Transport.

"We`re using versatile integrated avionics (VIA)-based technology, which is coming from the new Boeing 737-700. We will have a flight management system, display system and VMS [VIA maintenance system]," she says. "The display system will be six-across, flat panel displays - the same display we`re using on other Boeing aircraft. It uses the AMD 29050 processor. From an operational standpoint, the pilots will be able to go from an MD-11 to an MD-10 with very little new training."

The VIA computer, which includes flight management and displays, will offer a 20 percent spare installed throughput for the MD-10, with room in the computer to double its capacity for future needs. The VIA uses generic boards and, tapping a development from the Boeing 777, can partition software to ensure programs do not conflict. Most of the avionics hardware going into the MD-10 is essentially what Honeywell is installing for the new Boeing 717.

While the same approach could be used with other old aircraft - such as DC-9s and MD-80s (precursors of the Boeing 717) - Perillo says it would not add much in the way of new functionality. Most of those aircraft, he explains, were upgraded along the way to a far greater extent than the DC-10 or KC-135.

"The point to this program is FedEx did a lot of study and determined they could keep their DC-10s in service for at least another 20 years - and if they upgraded the avionics, it would pay for itself in reduced maintenance costs," she says. "And keeping an older aircraft in the air is much more cost-effective than buying new ones, in this case."

Honeywell officials are talking to the military about performing similar upgrades to fleets of KC-135s and KC-10 tankers. Meanwhile, the MD-10 is scheduled to make its first flight in December or January, beginning a one-year flight test program.

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U.S. Air Force fighter pilots are operating cockpit-development simulators developed at Boeing and at Lockheed Martin to design a tactical display system for the future F-22 jet fighter.

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The TRW modular avionics design combines various avionics functions into one integrated rack system, which reduces size, weight, and lifecycle costs.

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The Honeywell-designed avionics system for the MD-11 jetliner upgrade features large displays and a "glass-cockpit" design.

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Maintenance crew members can easily fault- isolate TRW avionics modules on the flight line.

Avionics designers prepare for the new era of `free flight`

Whether it is called the Future Air Navigation System (FANS) in the Pacific Rim or Communications-Navigation-Surveillance/Air Traffic Management (CNS/ATM) in Europe, the concept of "free flight" is moving rapidly along an international timeline toward global implementation by 2010.

In its simplest terms, free flight applies the latest technologies - from the Global Positioning System to cutting-edge avionics and communications - to enhance communications between aircraft and air traffic controllers, improve safe navigation, and increase flight capacity. Ultimately, pilots would be free to choose their routes and even safely change routes in flight. For the airlines, that would mean using the most economic, fastest or most direct route for each individual flight.

Achieving that goal will require a variety of hardware and software upgrades.

Experts at the TRW Avionics Systems Division in San Diego tout their Reconfigurable Processor of Legacy Avionics Code Execution (RePLACE) as a software solution enabling users to replace the hardware while continuing to use legacy software. RePLACE currently has only a military market, but TRW sees commercial potential as part of the free flight environment.

"What is needed there is communications-navigation-surveillance, which is similar to our military work in communications-navigation-identification," predicts Gary Kirchoff, director of business development for TRW Avionics. "We are most likely going to form alliances to do that rather than trying to enter the commercial avionics world by ourselves."

Designers at Honeywell Air Transport Systems in Phoenix already are incorporating free-flight capability into more than 100 DC-10 jetliners, many being converted from passenger to freighter service, for Federal Express Corp. in Memphis. Those elements, including satellite communications and the Traffic Collision Avoidance System - better known as TCAS - are included in a complete cockpit replacement, using the more modern MD-11 cockpit, with the resulting upgraded aircraft being re-certified as the MD-10.

"Honeywell formed WorldNAV, which is our initiative to position the company for the emerging CNS/ATM and Global Air Traffic Management (GATM), coined by the U.S. Air Force as the military equivalent of CNS/ATM," notes Cole Hedden, emerging markets segment leader at Honeywell Defense Avionics Systems in Albuquerque, N.M. "You now have the commercial world changing the regulatory environment dramatically in the next 10 to 15 years and the military having to play catch-up. In a true free flight environment, there can be no military-exclusive routes.

"The civil world is pushing that, not the military - but the military flies in that same environment and they will have to have [free flight] capabilities, even though in many cases it will not advance their warfighting capability," Hedden says. "And these are not trivial changes. What the military is looking at, just to be able to fly in civil airspace, will require significant changes in every platform that flies, from the least perhaps in helicopters to the most in a tanker. "

Given that, the military is looking to avoid spending its own limited money on a unique approach, opting instead to incorporate commercial solutions. And with airlines already operating within a FANS environment across the Pacific, senior Pentagon officials are making a major push to identify those options and how they can best be assimilated into military aircraft. - J.R.W.

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These communications/navigation/identification modules from TRW are part of an interchangeable avionics concept that will help aircraft designers prepare for the new era of "free flight."

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