An air taxi flies on the Alaskan Peninsula

South Naknek, a small village in western Alaska, is virtually isolated from the "outside" world. Frozen rivers and lakes and harsh terrain make traditional roads and waterways impossible to construct or navigate.

If it weren't for the single-engine planes that serve as "air taxis" for much of the region, children couldn't get to school, the sick wouldn't get medicine, and fuel and other necessities would be unavailable.

There are hundreds of villages just like South Naknek dotting the vast frontier of America's largest state. Air travel is the only means of transportation for these small communities. "When children set out for school in the morning, they watch for a plane to pass over the village's main street. That's their notice to get ready. Then, the plane circles back to collect children who are on their way to a regional school. That's how they get to class each day," explains Jim Chadwick, technical director, MITRE's Center for Advanced Aviation and Systems Development (CAASD). "Air travel has become the way of life in Alaska."

Unfortunately, due to a multitude of factors, air travel in Alaska can be difficult and dangerous. In fact, there is a fatal air accident in the state every nine days. That's 10 to 15 times higher than rates in any location in the continental United States. Fortunately, an advanced air safety system using technology developed by MITRE CAASD is helping reduce the hazard of air travel in Alaska. Under the Capstone effort (a Federal Aviation Administration (FAA) project developed as part of the Safe Flight 21 initiative), 150 small Alaska planes have been equipped with a unique avionics system that includes integrated data link communications, global positioning satellite systems, and a terrain data base. The result: a significantly reduced accident rate in western Alaska.

The Hazards of Air Travel

While Alaska may offer some of the most breathtaking scenery in the United States, it also presents some of the most dangerous—especially for the air traveler. For one thing, only small single- and twin-engine planes can accommodate the needs of residents in these tiny communities, since pilots must take off and land on runways that sometimes also serve as a village's main street. Routine hazards for these small planes include weather that changes from blue skies to dense fog in the blink of an eye, and a lack of surveillance radar and other equipment that makes mid-air collisions all too frequent. "Controlled flight into terrain is a very common cause of accidents," explains Chadwick. "Planes fly into mountains because they can't see that the land elevation ahead of them is increasing. Sometimes it's impossible to determine where the sky ends and the ground begins. Everything is white in the winter." Similarly, pilots can face catastrophe when trying to cross a mountain range through a slim pass. "Since they don't have any other awareness capabilities, they can get into real trouble if fog sets in and they can't navigate through a very narrow piece of airspace. That's a bad time to fly blind."

There is also tremendous danger even when an accident doesn't directly result in fatalities. In fact, many people survive the accident only to die from exposure because they can't be found. "The problem is because of the lack of radar coverage, search and rescue teams often don't know where to start looking," according to Ed Hahn, a CAASD principal engineer.

Understanding the Challenge, Finding a Solution MITRE has supported the FAA on numerous air-safety initiatives for many years. When Chadwick first visited Alaska a decade ago, he saw the need for a system that would provide radar-like services to planes supporting small villages throughout the state. "I was on vacation," he explains, "but I'm a pilot, and I see things from a pilot's point of view." With co-workers, he drafted a white paper for a cost-effective communication infrastructure that would allow an airplane to transmit information on its location, speed, and altitude to other planes in the vicinity and to strategically placed ground stations that were connected to an air traffic control center. This concept is called Automated Dependent Surveillance-Broadcast (ADS-B), and it has been around since the 1960s. MITRE was the first to optimize and apply the concept for the aviation community in Alaska. Next, a MITRE-sponsored research project was approved and a prototype developed. It included an air-to-ground radio link that transmits and receives surveillance and weather data for more than 120 miles called the Universal Access Transceiver (UAT); a cockpit display monitor that provides a moving picture of maps, weather, and the position of other ADS-B equipped aircraft; an integrated global positioning satellite system receiver; and integrating software developed by MITRE. "We went to the Florida Institute of Technology and tested our prototype system on the ground and in the air," explains Chadwick. "We needed to test the range of the equipment, particularly the UAT radio link, to determine how well it would perform in real-world situations."

Installing Capstone equipment in a small Alaska plane costs $15,000-20,000. Considering the advanced capabilities included in this avionics package, that's real value for the dollar, and the costs are expected to come down in the future as production numbers increase. Since the system is still under evaluation, the Capstone project picked up the tab for all associated costs, including the costs for the 150 equipped planes.

With the success of the initial prototype, UPS Aviation Technologies, a subsidiary of UPS, also showed interest in the technology. "They wanted to use the ADS-B technology and the UAT radio to improve on-time package delivery. We gave them a license to build the radio as a commercial product and they tested it in the Ohio Valley in 1998. They're still using it today."

Capstone Takes Flight

In the late 1990s, the FAA established the Capstone project to address the air-safety crisis in Alaska. In part, this effort was approved due to high interest in developing and implementing the UPS system, based on the MITRE technology, which had demonstrated so much promise. Working side by side with the Capstone team and UPS AT, MITRE helped build and integrate a system in a process that included feedback from numerous organizations in Alaska—including the Alaska Pilots Association, Alaskan Air Safety Foundation, and the University of Alaska at Anchorage.

"In addition to providing pilots with information needed to avoid hazardous weather, mid-air collisions, and collisions with terrain, the system provides aircraft identification and position information—via a ground and satellite infrastructure—to controllers at the Air Traffic Control Center in Anchorage, even though Anchorage is hundreds of miles away," states Jim Cieplak, a CAASD principal engineer.

"With the Capstone technology, controllers in Anchorage can control planes out of their typical radar range and provide for much safer approaches to airports such as Bethel that previously relied on visual flight rules to guide planes at landing. This is the most important aviation advancement since the advent of air traffic control radar," says John Hallinan, FAA's Capstone Program Manager. "This will save hundreds of lives in Alaska."

Says Chadwick, "MITRE was deeply involved in developing the system architecture, software and hardware development, and systems integration. In addition, MITRE aided the University of Alaska at Anchorage on an important training program for the pilots who would be using the system. A lot of pilots know GPS, but they now need to understand how to read and understand all the information that is provided on their display."

Currently, 150 planes have been equipped with the Capstone avionics package. "The display is very straightforward," says Chadwick. "If a pilot is flying in a safe area at a safe elevation, the display shows the plane in the 'black' zone. If it starts to veer toward a mountain—a distinct possibility if fog develops suddenly while flying through a mountain pass—the display will show the plane is heading toward a yellow or red area."

Furthermore, "the display provides the pilot with a real-time depiction of the weather, thereby allowing him to avoid hazardous weather conditions, a major accident factor," says Jeff Mittelman, the MITRE CAASD Capstone project manager. While pilots aren't encouraged to fly blind, the avionics package allows them to fly safely when caught in adverse situations. With this success in western Alaska, plans are under way to begin installing Capstone packages in other parts of the state, beginning with the southeast area around the capital, Juneau.

—by Nadine Monaco

Page last updated: February 22, 2006 | Top of page