Military, Products

What’s New With CAAS?   

By By David Jensen | October 1, 2010
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The Horizontal Situation Display-Hover (HSDH) displays hover reference symbology and steering cues, allowing the user to maintain precise orientation to the surface during challenging, complex and dynamic hovering and external load missions in adverse or nighttime conditions, such as brownout. The operator can analyze a hover reference point (small home plate symbol), velocity and acceleration cues, hover horizon line (dashed white line), direction, vertical position, and altitude information. Rockwell Collins

A principal reason helicopter operators such as the U.S. Army’s Special Operations Force (SOF) selected Rockwell Collins’ Common Avionics Architecture System (CAAS) for its rotorcraft cockpits is to ensure flexibility to accommodate ready growth. CAAS’ modular open systems architecture (MOSA) permits expansion through software upgrades. It works much like a desktop or laptop computer; install a CD—or with CAAS, a PCMCIA card—then boot up the system and, voila!, you have a new application. Of course, factors such as safety, security and ruggedness make the airborne system a bit more complex. But the principle is the same.

CAAS has accommodated growth since its requirements were first constructed. Advancements have included more and newer communication, navigation, surveillance, flight controls and survivability equipment, along with a brownout hover page. But to accommodate presumptive future growth, Rockwell Collins recently announced the first major hardware upgrade to CAAS since the system was fielded in 2003. The hardware upgrade is accompanied by a software upgrade. During Rotor & Wing’s recent visit to the avionics manufacturer at its headquarters in Cedar Rapids, Iowa, company officials also discussed the development of new capabilities on the horizon for CAAS, such as synthetic vision, wire and obstacle detection, and enhanced situational awareness in brownout conditions.


Discussions took place in Rockwell Collins’ recently established laboratory dedicated to helicopter electronics. Launched, in part, because of CAAS’ expanded use and capability, the lab occupies a secure building—once dedicated to Army programs—on the company’s sprawling campus.

“We found it made more sense to have all the CAAS rotorcraft programs move to this lab,” says Boe Svatek, program manager in Rockwell Collins’ Government Systems division. “So now we’ll soon have [U.S.] Navy, Marine Corps and Coast Guard programs that all have CAAS located here.”

Major Upgrade

For the hardware upgrade, CAAS users are preparing to swap out the system’s IBM Power PC 750 processors, now obsolete, with the PPC 7448 processors from Freescale. Designed for embedded network control and signal processing applications, the new PPC 7448s provide twice the operating speed and twice the memory of the old 750s, thus allowing for significant systems growth, according to Svatek.

The new processors are a common core component for CAAS hardware, which includes a general-purpose processor unit (GPPU), multifunction displays (MFDs) and control display units (CDUs). Replacing processors in the CDUs and GPPUs will be fairly simple, according to Svatek. “All you need to do is replace the old processors with the new, retest them and then return the unit to the field,” he explains. “Upgrading the MFD will be slightly more complex because in addition to replacing the two processors [mission and display], adhering to the MFD specification power limit also drives a change to the efficient backlight already fielded in our newest units.”

In addition to the GPPU, MFD-268C3 displays and CDU 7000s, CAAS’ common core assets include a data concentrator unit (DCU) produced by the Huntsville, Ala.-based Defense and Aerospace Systems division of Sanmina-SCI Corp.

The CAAS architecture was designed to host third-party applications. Examples include a digital map application produced by Harris Corp. using a U.S. Department of Defense database, an aircraft performance database provided by the U.S. Army Aviation Engineering Directorate and algorithms to automatically check the viability of flight plans and alternate flight plans against “bingo” fuel and hot/high hover requirements.

The PPC 7448 processors have already been installed in SOF’s A/MH-6M “Little Birds.” These helicopters have a Rockwell Collins cockpit that is somewhat unique to the CAAS system in the 160th’s larger helicopters, though it does include a common CDU. Although installing a full CAAS system in the Little Birds would simplify the Army’s avionics inventory, such a program probably will not take place, according to Svatek. CAAS displays are AC powered and, unlike its heavy- and medium-lift brethren in the 160th, the A/MH-6M has limited AC power distribution.

Installation of CAAS upgrades takes place at Rockwell Collins’ service centers, where the processors undergo factory testing in a controlled environment. Upgrades will include a new version of LynuxWorks’ Lynx OS178B operating system, where the applications reside in partitioned memory. The OS178B is compatible with the new 7448 processors.

The software upgrade accompanying the PPC 7448 processors includes application code for backward compatibility with the older Power PC 750s. It also provides reserves for new capabilities, such as JTRS radio control and data management, terrain avoidance warning, health and usage monitoring, and cognitive decision aiding, among others. (JTRS, or Joint Tactical Radio System, is a software-defined voice and data communications technology that is set for U.S. military use this year.) The software also incorporates capabilities unique to the different needs of CAAS users.

SOF’s 160th Aviation Regiment (Airborne), with its array of challenging missions, has been the driving force behind many new CAAS applications, which are developed for the unit’s MH-47G Chinooks and MH-60L/M Black Hawks.

Night Stalkers, First

The 160th Aviation Regiment, nicknamed the “Night Stalkers,” began equipping its Chinooks and Black Hawks with CAAS in 2003. The avionics system subsequently caught the eye of “big” Army, the U.S. Coast Guard and the Marine Corps.

Selecting CAAS for its CH-47F Chinooks, the Army has been flying with the system in Iraq and Afghanistan for about two years. The avionics also are installed in the Army’s two UH-60MU Black Hawk test aircraft, currently in the testing and evaluation stage. In the UH-60MU, the CAAS display architecture was scaled back to four displays, versus five in most platform integrations. The baseline UH-60M, currently in production at Sikorsky Aircraft, also has four displays, which are comparable to those in the 60MU. The MFDs in both models are in landscape format, not the portrait format in the Chinooks and other CAAS-equipped helicopters.

CAAS was also chosen for the Army’s ARH-70 Armed Reconnaissance Helicopter before that program was discontinued and succeeded in 2009 by the Armed Aerial Scout (AAS) program. The ARH program further highlighted CAAS’ scalability; the smaller helicopter was to fly with only two MFDs and a single GPPU. Nieuwsma says Rockwell Collins “is working with a number of potential OEMs” that plan to enter the AAS competition.

The Coast Guard selected CAAS as an upgrade for its 42 MH-60T Jayhawk search-and-rescue (SAR) helicopters. And the Marine Corps chose CAAS technology to modernize its fleet of VH-60Ns (for government VIP transport) and outfit its new heavy-lift Sikorsky CH-53K Super Stallion, for which a critical design review was completed in early August. The Marines plan to acquire more than 150 CH-53Ks to replace its CH-53Es, which have been on duty for more than 25 years.

More than a pilotage tool, CAAS also combines mission capabilities. For example, it provides stores management for armed helicopters and will report such critical information as number of available rounds, chaff and flair inventory, and a rundown of other integrated survivability equipment.

In addition, CAAS incorporates Blue Force Tracking, which basically informs Army pilots who are the “good guys” and who are the “bad guys” on the battlefield. And, for the U.S. Coast Guard, it includes an enhanced position location reporting system (EPLRS), for directional navigation to, say, a vessel in distress.

Forest Lightle, who works in Rockwell Collins’ new lab dedicated to helicopter avionics, sits in front of CAAS MFDs for the CH-47 Chinook. He is a Chinook pilot and lieutenant in the Iowa Army National Guard. Photo by David Jensen


Beyond CAAS architecture, MOSA exists throughout Rockwell Collins product lines, in its Pro Line suite for business jets, avionics for Boeing’s new 787 and programs for a variety of military cockpits. New developments for one market may well migrate to another market.

“About 15 years ago, Rockwell Collins realized it needed to develop a new architecture for its avionics,” says David Nieuwsma, vice president and general manager of mobility and rotary wing solutions at Rockwell Collins. The intent was to develop Common Reusable Elements (CORE) that can be adapted for both government and civil markets.

MOSA was adopted to help avionics development keep pace with, and take advantage of, new technologies in the consumer world, thus speeding up the development and approval process, which traditionally took years. Adopting MOSA was not without a change of thinking at Rockwell Collins. The key word in MOSA is “open,” which means a third-party (competitor) or multiple suppliers can, by adopting appropriate protocols, supply applications to CAAS users.

“We provide third-party development tool kits, and we typically convey government-purpose data rights to our domestic military customers,” says Nieuwsma. Thus, Rockwell Collins must compete to supply new capabilities for a system it developed.

The company’s open system architecture was first applied as the Flight2 avionics suite for the U.S. Air Force’s KC-135 Global Air Traffic Management (GATM) program, launched in 1997. GATM components exist in CAAS; however, the cabinet-based architecture employed for the large, four-engine tanker had to be modified to fit in relatively small helicopters. “You don’t have a big eBay in rotorcraft, so you have to install boxes in nooks and crannies,” Nieuwsma explains.

Packaged as a federated system, CAAS’ processing elements communicate with each other through a 100 base T Ethernet backplane, which transmits at 100 MBits per second. It is not unlike a wireless network in an office environment except modified to be more safety critical.

Indeed, Rockwell Collins has adopted IT principles and commercial off-the-shelf (COTS) technology wherever possible in order to provide the latest technology at a low cost to its CAAS customers. For example, to transmit uncompressed video from processors to cockpit displays, the company applies the SMPTE 292 standard (1.5 Gbit per second) used for the high-definition televisions found in many homes. An Evolving System

To ascertain the evolving needs of its customers—in terms of new applications and/or training—Rockwell Collins relies on two sources. One is field service engineers, which the company has stationed with CAAS-equipped helicopters, including with the 160th Aviation Regiment in Iraq and Afghanistan. These company representatives monitor CAAS use and report complaints and suggestions that probably will result in improvements issued in a software upgrade.

The other source of information from the field is a “CAAS user group” that includes Army, Marine and Coast Guard pilots who meet at least biannually and provide feedback and make suggestions. Their comments, along with input from the field engineers, often contribute to modifications in the user interface.

Consequentially, the CAAS cockpit has been refined to be more intuitive. On the system’s displays, important elements have been made easier to find through grouping and flagging; screens are less cluttered and incorporate more pleasing color schemes; graphical functions are located to support visual scanning based on eye tendencies, and page trees have been designed to ensure that the most used functions appear at top levels.

Operators and OEMs outside the U.S. have chosen CAAS architecture, too. For example, the system is installed in international Chinooks to be flown in Canada and Italy. In addition, the German Air Force is upgrading its CH-53Gs with CAAS avionics. In addition, AgustaWestland has installed CAAS-derived displays in its AW101 and medium-lift AW149 helicopter now in development, and selected CAAS-based avionics for its recently unveiled AW169. Currently, Rockwell Collins plans to form an international CAAS user group. “We’re in the planning stages of standing up an international CAAS users group and are soliciting for interest,” says Nieuwsma. “The intent is to host a kickoff meeting in the next six months.”

All told, CAAS and its derivative components have been installed on more than 300 helicopters worldwide and are projected to be on more than 3,000 helicopters. According to Nieuwsma, about half are forward-fit installations and half are retrofit. CAAS is retrofitted in most SOF helicopters.

Battling Brownout

Not surprisingly, given CAAS’ use in the desert environment in Iraq and Afghanistan, operators have sought an application that allows safe landings when the rotor wash creates brownout, part of an overall safety problem for helicopter pilots, referred to as “degraded visual environment.”

Brownout can create spatial disorientation and cause pilots to lose attitude control, resulting in rollover. Some users, notably the U.S. Army, have initially chosen to resolve the brownout problem through training. Were it to seek a technical solution, the Army would view the need for three components, according to Svatek. Those are advanced cueing, advanced flight controls and an optimum see-through sensor. Army Chinooks and Black Hawks have the advanced automatic flight controls, though the Little Birds do not. All three of the helicopters types have advanced cueing developed by Rockwell Collins for the CAAS displays. Symbology for display cues was the result of a program lead by the Brownout Situational Awareness Unit of the Aviation Applied Technology Directorate (AATD) out of Fort Eustis. The Army’s Cargo and Utility program management offices tasked the unit to develop and test ways to prevent accidents due to brownout. Meanwhile, the U.S. Defense Advanced Research Projects Agency (DARPA), too, has sought a brownout solution through a research program known as “Sandblaster,” according to Nieuwsma. On the hover page, during a brownout condition, pilots can view on the CAAS MFDs a velocity cue and distance above the ground in one-foot increments. Concentric circles on the display guide the pilot safely to the landing zone. Rockwell Collins officials describe the display as a “god’s eye view” (like looking straight down) of the landing spot. Data prompting the cues can derive from various existing sensors, including air data systems, radar altimeters and GPS/inertial navigation systems.

Early testing found that the MFDs, not head-up displays (HUDs), were preferable to provide cueing during brownout. “Experimentation has shown us that pilots’ natural instinct is go heads down in an IFR situation, and the same is true in a brownout situation,” says Svatek. “However, as pilots transition to day/night HUDs and training, tactics and procedures evolve, HUD relevance will undoubtedly increase substantially.” Also part of a degraded visual environment for helicopters are unseen wires and other obstacles. Various solutions have been forwarded, including laser transmitters that emit radiation near the infrared wavelength and a line-scan system fed by multiple antennas. Rockwell Collins France, in Toulouse, successfully tested this past summer a wire and obstacle warning system. The system incorporates frequency modulated continuous wave (FMCW) radar attained through a collaborative technology and licensing agreement with a Dutch company, TNO.

Wires pose a particular hazard for military and paramilitary helicopter operators flying in wire-rich Europe.

Another tool to overcome a degraded visual environment is synthetic vision, which uses a database to “look” at the terrain below. “A lot of new work is being done to enhance synthetic vision by using onboard sensors to validate the data,” Nieuwsma reports. Such a system would have sensor-driven imagery from a forward-looking infrared camera, laser imaging, millimeter wave radar, radar altimeter or combination of sensors overlaid on database-driven map. CAAS allows the system to be “sensor agnostic,” he adds and says he expects prototype testing to begin before year’s end.

In Europe, Rockwell Collins is finalizing commercial certification of its synthetic vision software. It has been working closely with AgustaWestland to further the technology and will rehost synthetic vision software to the new 7448 processors based in AgustaWestland displays. From input from military and paramilitary operators, the European OEM has made synthetic vision a required CAAS application, says Nieuwsma.

Rockwell Collins

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