ATM Modernization

Product Focus: Voice Switches: What’s Next?

By Charlotte Adams | November 1, 2003
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Producing voice switches isn’t rocket science, but air traffic controllers can’t do without them. Aside from en route equipment, which has more time left before replacement becomes necessary, many switches in the U.S. National Airspace System (NAS) are aging or coming up to the end of their availability under current contracts. As a result, the Federal Aviation Administration (FAA) is considering a new program to procure a scalable switch that would cover the needs of terminal controllers and automated flight service station (AFSS) specialists.

Known as the Integrated Communications System (ICS), this program-to-be could involve as many as 200 switches, worth as much as $100 million. If the concept passes muster, award of an indefinite delivery, indefinite quantity (IDIQ) contract is expected in 2005, with deployment beginning in 2006 or 2007. The ICS concept is regarded as a relatively near-term program, with a time horizon of approximately 10 years from the date of award.

The scope and timing of ICS are not yet clear. An "A-76" process is under way regarding the outsourcing of AFSS services. If the AFSS function and its equipment should go to a commercial enterprise, it is unclear whether the resulting entity could buy voice switches under ICS.

The existing terminal voice switch procurement contracts are in their last year of availability, although these contracts may be extended for a year, with a one-year option on top of that. If the contracts are not extended, a "bridge" program could be put into place until ICS can get started. The potential constituency for a new program is fairly large: there are about 60 AFSS stations and approximately 200 terminal facilities. ICS is thought to have a requirement for switches supporting up to 150 positions and controlling as many as 200 frequencies. Large terminal radar approach control facilities (TRACONs) and consolidated AFSSs could use this size equipment.

If ICS becomes a program, possible bidders could include Frequentis USA and Northrop Grumman, who faced each other in the AFSS VS (voice switch) contest last year. That program was awarded to Northrop Grumman (Litton Denro) in June 2002, was successfully protested by Frequentis and was ultimately cancelled by FAA. If ICS is approved, observers expect a request for information (RFI) by early summer and a competition next year.

ICS is an opportunity "to use as much modern technology as possible," to reduce the cost, the physical sizes required and the complexity of the switching systems, says Robert Pfister, president of Frequentis USA. He expects to see a high degree of commonality in the equipment. While there would be small differences in screen layouts between the applications, in the switch core, "it’s going to be a matter of stacking more and more cards to make it handle more interfaces, more lines."

Including both terminal and AFSS facilities in the same program makes sense, considering the approximately 96 percent commonality between AFSS and terminal requirements, says Bill Syptak, product lead for voice switches and recorders, with FAA’s Communications, Navigation and Surveillance Systems Office.

ICS is currently unfunded. As of press time, FAA officials hoped to have an initial requirements document approved any day and an investment analysis readiness review by November. "The approach of buying a common platform is pretty well accepted," but an analysis of alternatives will look at several options, says Syptak. A full investment analysis is expected to begin this year and be completed in 2004.

The remaining voice switch users are the en route centers. A program concept called NAS VCOM (voice communications) is looking at requirements for en route voice communications switches, as an initial core task. NAS VCOM, however, is at a much earlier stage of consideration than ICS, looking at next-generation voice switching needs, including the concept of "one switch being able to do everything," says Jim Williams, FAA’s integrated product team leader for communications. If NAS VCOM comes to fruition, implementation could begin in the 2010-2011 time frame, observers say.

It’s anticipated that decision makers will consider ICS "a good step" because the equipment is needed now, says Stephen Glowacki, the national technical representative on voice switching of the National Association of Air Traffic Specialists (NAATS), who staff the AFSS. There’s been a massive effort to combine the requirements documents for AFSS and terminal switches, he says. "It’s the first step toward ‘commonizing’ voice switching equipment across the NAS."

According to Glowacki, FAA’s en route voice switches need to be fully replaced by 2014. But half of the AFSS voice switching equipment will come up to the end-of-life-cycle milestone in six months to a year. And the other half will arrive at that point six months after the first group hits it. Depending on failure rates and parts available, however, switches could continue in service for another five to 20 years after the last systems have been bought.

Wireless Controller Positions

UK-based Drake Electronics Ltd. has pioneered a new twist in air traffic control (ATC) voice switching. The company’s FreeSpeak product allows the addition of a wireless position to Drake’s wired voice switches, so that an air traffic controller supervisor can stay in communication with an aircraft and other controllers while moving around. The concept seems to be catching on. A Far Eastern customer plans to install FreeSpeak at a small area control center, in parallel with the deployment of a Drake wired voice switching system. The application should be up and running next year, says Peter Stallard, Drake’s systems and applications manager. Coverage can easily be extended to the facility’s adjoining tower with the addition of further antennas, he adds.

A second ATC use for the digital wireless intercom system could be for emergency communications in the event that controllers for some reason have to vacate the tower. This application also would rely on the central wired switch or a duplicate wired switch, Stallard says. In the absence of obstructions, FreeSpeak allows a controller to move up to 984 feet (300 meters) from the nearest antenna. Multiple antennas can be used to cover a large physical area. Inside buildings, the range is limited to about 164 feet (50 meters).

The product consists of a "belt pack" with an embedded computer that plugs into a standard headset. The belt unit provides enough intelligence to show the status of calls and allow the controller to establish communications on any allocated frequency. The system provides built-in quality-of-service checks on the communications link and changes frequencies automatically to avoid interference. It operates in a specially allocated digital enhanced cordless telecommunications (DECT) band.


CML ATC Technologies

Drake Electronics Ltd.



Northrop Grumman (Park Air and Litton Denro)

Redflex Communications Systems Pty. Ltd.

Schmid Telecom


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