Concerns voiced over pilots' abilities to comprehend red-red-green light sequence
General-aviation groups have expressed cautious approval of a laser-based visual warning system (VWS) to alert pilots that they have violated restricted airspace over Washington DC. Demonstration of the system, which becomes operational on 21 May, has convinced sceptics the red-red-green laser light sequence will get a wandering pilot's attention, but whether they will know what to do when illuminated remains a concern.
The system of at least seven turrets, each housing red and green eye-safe lasers, has been installed to visually warn unauthorised or unidentified aircraft – those with no flight plan or transponder signal and unresponsive to air traffic control – that they have entered restricted airspace over the national capital. On being illuminated, the pilot should contact ATC and turn away to exit restricted airspace.
The VWS has been developed by the North American Aerospace Defense Command. Radar is used to track the aircraft and cue the turrets, which have a camera connected to a command centre to enable positive identification before illuminating the intruder. The low-intensity laser light is visible up to 28km (15nm) away by day and 37km by night, but only in visual meteorological conditions.
"The VWS will definitely get a pilot's attention, but understanding what it means is the challenge that security officials need to address," says the Aircraft Owners and Pilots Association. If the warning fails, the aircraft is likely to be intercepted by US Air Force fighters using flares to attract the pilot's attention. "This is not a tool to keep people out of trouble. If you've been lit up by this, you are already in trouble," says the Experimental Aircraft Association.
GRAHAM WARWICK/WASHINGTON DC
Source: Flight International