One of the biggest dangers facing helicopter crews around the world, and in current operational theaters in particular, is “brownout.” Rotor downwash can create clouds of sand and dust that obscure the pilot’s view at critical times, especially when landing. Snow and fog also bring their own low-visibility dangers.

A number of initiatives have been launched to provide a solution to the problem, which has caused the loss of several helicopters in Iraq and Afghanistan. Trials have shown that terrain-referenced systems can greatly increase pilot situation awareness in brownout conditions, as can imaging millimeter-wave (MMW) radar.

BAE Systems has developed an MMW sensor under its Blast (brownout landing-aid system technology) program and has recently successfully tested it during a two-week campaign in April at Yuma Proving Ground, Arizona. Weighing just 15 pounds and measuring seven inches in diameter, the 94-GHz sensor was mounted in the nose of a U.S. Army Bell UH-1 helicopter and provided excellent results when flown over known-obstacle courses.

The gimbaled Blast installation looks left and right up to 30 degrees. The full sweep is employed for wide-area awareness as the helicopter approaches the landing zone, but narrows as the aircraft flies lower, to focus on the critical area immediately ahead.

Imagery from the sensor can be shown on a variety of displays, including head-down screens and helmet-mounted sights. It could also be overlaid with FLIR or DTED (digital terrain elevation data) imagery to enhance obstruction awareness.