The Runway Incursion Problem

According to FAA statistics, the number of reported runway incursions in the U.S. has remained relatively constant over the last ten years.   A runway incursion is defined by the FAA to be “any occurrence at an airport involving an aircraft, vehicle, person, or object on the ground, that creates a collision hazard or results in the loss of separation with an aircraft taking off, intending to take off, landing, or intending to land.”  The FAA also categorizes incursions by their severity [FAA Runway Safety Report, August 2005].  There are four categories, with Category A being the most severe and Category D the least.  Category A is where the separation decreases and the participants take extreme action to narrowly avoid a collision.  Category B is where separation decreases and there is significant potential for collision.  Category D is where there is little or no chance of collision and no evasive action is required.   For the years 2000-2004, Category A and B incidents comprised 11 per cent of the total, with a total number of 150 such incidents.

PathProx Application

PathProx is an avionics-based solution for runway incursion detection.  PathProx provides timely alerts directly to the pilot for all runway incursion conflicts on the airport surface. The operational concept for PathProx provides the following safety benefits:

• Extend aircraft conflict alerting to the airport surface
• Improved prevention of incursions by providing early alerting
• Improved capability of pilots for detection of conflicts
• Improved response to incursions by providing timely conflict alerting.  This will minimize the number of the most sever incursions (near collisions) by allowing pilots to respond faster in taking evasive actions

Current ground-based incursion solutions are relayed verbally to the pilot by air traffic control.  PathProx eliminates the added time delays in having the controller in the loop.  The pilot is also able to take evasive action in a more informed manner.

PathProx Alerting

PathProx is designed to handle over forty different runway incursion scenarios.  The alerts are determined based on a combination of aircraft and vehicle states and conditions including location, speed, and track angle.  PathProx will provide two types of alerts, analogous to TCAS.

• Traffic Alert (TA) Caution: A TA is generated when the aircraft is either projected to be involved in a runway incursion with other traffic or an incursion has occurred that does not yet require evasive action.
• Conflict Alert (CA) Warning: A CA is generated when a runway incursion has been detected, and that the aircraft involved in the conflict need to take evasive action to avoid a potential collision.

The alerts can be annunciated visually as well as aurally.  A typical visual display would be on a moving map or CDTI (Cockpit Display of Traffic Information) as shown on the graphic.