Radar would help pilots navigate snow, dust - Army News | News from Afghanistan & Iraq - Army Times

Radar would help pilots navigate snow, dust

The Army has developed a radar-based system to solve a major problem for helicopter pilots — dust or snow that blinds them on landing, which is the leading cause of Army aircraft accidents.

The Army plans to install radar systems on 10 UH-60L Black Hawks that will enable pilots to see small hazards through dust, sand, snow and bad weather, according to radar integrator Sierra Nevada Corp. and Army officials.

Sierra Nevada’s radar is one in a new class of systems meant to help pilots see and fly better; all to prevent what has become the leading cause of airframe losses in the Army, according to a Defense Department report to Congress.

Brownouts, whiteouts and the like — collectively known as degraded visual environments — are a common problem for pilots, especially in Afghanistan, Army officials said. Blinding plumes of dust can envelop helicopters as they land, increasing the likelihood that pilots will lose their bearings and drift into unseen obstacles.

A 2009 Defense Department rotorcraft survivability study found that 80 percent of rotorcraft losses were due to non-combat and nonhostile-related incidents.

“What’s driving the requirement are the environments we fly in,” said Maj. John Cochran of the Army Aviation Directorate. “Afghanistan is very mountainous and very dusty. In a given day, you could fly from the dust conditions in Kandahar into the southern Hindu Kush, and find yourself in clouds and snowstorms. The last thing you want to do between two 15,000-foot mountains is lose your ability to see.”

Moreover, the high frequency of aerial missions and the abundance of unimproved landing zones contribute to the rate of these accidents, according to Layne Merritt, director for engineering and technology at the Army aviation program executive office.

The problem is common to Afghanistan and Iraq, and pilots historically have relied on their training and flying techniques to avoid accidents. However, amid rising numbers of airframe losses, the Army has sought materiel solutions that provide “see-through” imagery.

“If you’re sitting in the cockpit, you can see rocks and bumps, and it’s like you’re there,” Merritt said. “[The radar system is] even better than most people’s eyesight.”

The program executive office for Army aviation is creating an Army aviation strategy to develop DVE-fighting capabilities, Merritt said. In the meantime, the Sierra Nevada system would be fielded not as a program of record but as a quick-reaction capability.

A former Defense Advanced Research Projects Agency program called Sandblaster worked to integrate sensor technology with workload-reducing displays and advanced flight controls that provide automated handling — so-called “fly-by-wire” technology.

“There are numerous development programs in government and every service has one or two,” Merritt said. “What’s different now is that we think the technology is mature enough that we can go ahead and field it.”

The ability to fly in degraded visual environments has both safety and offensive potential, Merritt said. Pilots could one day use dust clouds as cover while attacking an enemy.

“They’re no longer shooting at the cockpit door,” Merritt said of enemy fighters. “They’re shooting at a dust cloud. Big difference.”

The defense industry has offered competing sensor technology, including laser radar, millimeter-wave radars or infrared imagers, all of which see through obscurants to create a picture on a cockpit display. So far, the Army has not settled on one technology by itself, Merritt said.

The obstacle before now was that the systems were too heavy or the display systems were too rudimentary, Merritt said. Today, he said, the Army believes it can find an effective and affordable solution.

The Sierra Nevada system would be fielded to Afghanistan in the summer of 2013 in response to an operational needs statement, said Jennifer Jensen, vice president of business development for Sierra Nevada. She said the Army and the company were in final negotiations.

Called Helicopter Autonomous Landing System, or HALS, Sierra Nevada’s system uses a 94 GHz radar mounted on the aircraft’s nose.

The images it produces are overlaid on a synthetic map on a cockpit display. Terrain and obstacles can be colored green, yellow or red, depending on the danger they present — their proximity and placement in the flight path.

The sensors and display also work alongside an advanced flight control system that improves the aircraft’s handling and allows for precise movements, something Merritt said the Army is eyeing to help reduce DVE-related accidents.

An advanced flight control system might, for instance, be used to hover the aircraft 30 feet above a designated point and initiate a slow descent, one foot at a time. It might also hold the aircraft steady.

“Say you’re in a cloud and can’t see. You couldn’t see you’re drifting, and you’d eventually drift into an obstacle,” Merritt said. “Now these aircraft can land and not drift, and that’s huge.”

Such advanced flight control systems — already in the CH-47F and UH-60M aircraft — are the future of rotorcraft aviation, according to aviation industry officials.

However, these automated systems are best used in concert with sensor systems, said Paul Cooke of BAE Systems’ defense avionics division. He notes that even if a pilot has advanced flight controls, he would need help seeing objects in transit on the ground.

BAE offers BLAST, the Brownout Landing Aid System Technology. The system uses a 10-pound active 94 GHz millimeter-wave radar to overlay images on existing terrain data in a cockpit display — helmet-mounted or otherwise.

The active sensor detects transient items, such as soldiers and vehicles that aren’t in the static terrain data on maps, Cooke said.

Cooke speculated the Army may pursue a multispectral solution because of the weaknesses of individual sensors working alone. For instance, infrared sensors that detect changes in heat don’t work as well in the rain, night-vision sensors work poorly in absolute darkness, and radar-generated images can be imprecise or “blobby.”

“We like the obscuration penetration that 94 GHz has, and we like the size and weight of our sensor,” he said. “We think our ability to tell the height and geo-locate obstacles is precise enough to allow you to fly safely.”

Cooke said it was a long-held belief that DVE-related crashes were a problem with experience or training. However, such crashes persist amid a decade of war and among pilots with hundreds of hours of experience, which makes the case that technology is needed to help.

“We have more experience now and the accident rate is not all that different,” Cooke said, “so I think you’re starting to see momentum coalesce around a [materiel] solution of some type.”