Honeywell's comprehensive approach to solving the problem using radar is detailed in part in several patent applications published Dec. 5, one by four engineers, including the enhanced ground proximity warning system's (EGPWS) creator, Don Bateman; and another by Honeywell Aerospace's senior chief engineer for human factors, Ratan Khatwa, and a second author. The wingtip protection system described in the FCC documents could be a simpler implementation of the system, however.
The Bateman patent describes an airport surface collision avoidance system that detects and tracks “intruders,” evaluates and prioritizes threats to the wing, tail, engine nacelles or other parts of the aircraft; declares and determines actions; and issues alerts to pilots or ground personnel (tugs, baggage carts, fuel trucks, wing walkers and others). The alerts are transmitted via wireless connection from antennas located in the navigation light pods. The system would help pilots steer clear of buildings and obstacles, including other vehicles and aircraft, during all visual conditions.
Detection is carried out using a radar sensor placed in the existing navigation light fixtures in each wingtip and at the top of the vertical stabilizer, although Honeywell says passive optical or acoustic sensors are also possible.
In the cockpit, the pilot would potentially receive three types of alerts or warning information: visual, audible and tactile. The visual alert would be displayed on an electronic flight bag (EFB) or cockpit display, perhaps showing the aircraft wingtips outlined or a highlight of the obstruction. An aural alert could be a beeping sound from the existing EGPWS that increases in frequency as the obstacle gets closer, changing into a continuous tone for a warning, or possibly a voice alert of “Left” or “Right” to direct the pilots' attention to an obstruction. The information would also be sent via wireless transmitter in the navigation light module to alert ground crews to the threat, too.
The Khatwa patent relates more to displaying such information, and includes description of a top-down image of an aircraft on an EFB or flight display, with visual range rings at selectable values extending from both wingtips. Bateman notes that the sensor range will depend on time available to detect an intruder, evaluate and prioritize threats, and to declare and determine actions for the pilot or ground crews to take.
One notional display would show the primary targets (those located between each wingtip and the fuselage) as larger solid circles, and secondary targets (those outboard of the wingtip) as hollow circles. The system could also display the relative height of the obstacle, to show whether the aircraft wing or other part could safely taxi over or under it.
Honeywell tells the FCC in its request that the prototype wingtip collision system would meet all existing requirements for automobile radar and would be able to “share the band” with FOD radar. While the company continues to work with the FCC on the request, it is holding off on additional engineering and human factors developmental tasks pending the agency's approval to use the spectrum for ground-based aircraft.