Fielding a Low-Cost Solution to Runway Incursions

November 2012
Topics: Air Traffic Management, Avionics, Airports, Mobile Technologies
Some of the worst disasters in aviation history have occurred on the ground, during runway incursions.
Pilot views aircraft position on runway on mobile device screen.

The worst accident in aviation history—the 1977 collision of two Boeing 747s on a runway in the Canary Islands, which claimed 583 lives—resulted from a runway incursion. Currently, about 950 runway incursions, or RIs—where aircraft enter or cross an active runway without permission—occur every year. As the 1977 tragedy reminds us, some of the events have the potential for disastrous consequences. Thanks to the efforts of a team of MITRE engineers, however, the frequency of these incidents may soon decline.

Given the serious safety hazard RIs present, the National Transportation Safety Board has long made RI prevention one of its top aviation-related priorities. Many technologies exist to help address the problem, such as runway status lights and cockpit-based surface moving maps, which present pilots with a dynamic image of the airport, showing their own aircraft's position within it. Other technical solutions include the Runway Awareness and Advisory System, which not only provides a flight crew with information regarding the relative position of their aircraft to the runway but also voice announcements alerting them when they are approaching crucial intersections, such as runways. Similarly, the ASDE-X airport surface traffic management system uses complex algorithms to alert controllers of potential aircraft or vehicle collisions.

These technologies have the potential to go a long way toward reducing the incidence of RIs, particularly at major airports. But the cost of these solutions is high, thereby creating a gap in coverage at lower-volume airports such as those used by the general aviation (GA) population.

"The lack of GA coverage is important because GA aircraft are involved in 75 percent of all runway incursions," explains Steven Estes, a MITRE lead human factors engineer. "To provide better RI prevention coverage for the GA population, we need a low-cost solution that isn't dependent on airport infrastructure."

This understanding led to the creation of MITRE's Low-Cost Runway Incursion Prevention project, an internally funded research project launched three years ago under Estes' leadership.

Incursions Occur Despite Controllers' Instructions

A key finding of the MITRE team's initial research was that more than half of all RIs occurred even though the pilot had correctly read back the controller's instructions to "hold short" of a particular runway by stopping at the "hold line" before entering its surface. The three major causes of this, they found, were pilots who were lost, distracted, or had forgotten or misremembered the taxi clearance the controller had provided.

As a result, the team recognized that any solution they developed had to capture the taxi clearance instructions given by the controller. And they needed to do it in a way that small airports and private pilots could afford.

"We realized that GPS-enabled handheld devices like the Android, Blackberry, and iPhone were excellent platforms for a low-cost incursion prevention system," says Estes. "Pilots already own these devices, and deploying apps is relatively inexpensive. GPS ensures that the pilot isn't dependent on airport infrastructure, and all of these devices provide a variety of ways to input the taxi clearance."

In its first year, the Low-Cost Runway Incursion Prevention project investigated the technical and procedural feasibility of using handheld devices to prevent incursions. The research team created an application that uses speech recognition to capture the "hold short" instructions communicated by the controller, then present these same instructions on the handheld device's display panel.

A Multi-Faceted App

But the team didn't stop there. The application also tracks the pilot's position and uses an algorithm to compare it to the instructions the pilot has received.

"Once installed on the phone, the application monitors your position on the runway surface," Estes explains. "It watches your speed and your heading, and if it appears you're not going to stop at the hold line it will issue a warning, both audibly and on the display."

The results of the team's work were so promising after a year of development that the Federal Aviation Administration funded the project to continue the research, enabling the team to test its work, obtain feedback, and redesign the system accordingly.

"We tested the system with about 100 members of the Aircraft Owners and Pilots Association [AOPA] between November 2011 and January 2012," Estes says. "Basically, we provided them with the software to test at their home airports. Then we took the data from the tests and refined and improved the application."

The team recently completed its refinements and has now made the software available to commercial software developers. "They will take our code and integrate it into their existing applications," says Estes. "We created our system as a stand-alone application, but some of the feedback we received during the beta test with AOPA members was that a lot of pilots were already using an aviation app and didn't want to have to use a separate one. They wanted MITRE's app integrated into the one they were already using, so vendors will be adding our functionality to their existing applications."

Software Sharing Gets Apps Moving

Due to the safety criticality of the RI issue, the team wanted to make their results widely available to the community as soon as possible. The project opted to use Google Code, Google's software-sharing environment.

"One of our goals with this program was to keep it low cost, so we have open sourced the software, which means it's available free of licensing fees and royalties. This has allowed vendors to quickly add our capability to their existing products."

Aviation application vendor ForeFlight has already finished incorporating MITRE's software into its own ForeFlight Mobile application (the updated software became available in August), and several other vendors are considering doing the same.

—by Marlis McCollum

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