'Brown-out' testing allows safe landings

Driving in a dust storm with zero visibility can be nerve-racking, dangerous and sometimes fatal.  Imagine trying to land a helicopter or other aircraft in conditions often referred to as “brown-out,” and not knowing if you will land safely? Last summer, testing took place at Yuma Proving Ground to demonstrate a system called the three dimensional landing zone (3D-LZ) system to solve this problem.

Every day, pilots overseas are faced with landing in blinding and disorienting conditions, causing hundreds of crashes, deaths and millions of dollars in damage to military aircraft. Over one year ago, the planning phase began to conduct this test to improve sensor technology.

The system combines high performance, dust tolerant imaging laser/radar (ladar) technology. It provides pilots with landing zone situational awareness as well as aircraft guidance and obstacle avoidance information.  

“The difference between a laser and ladar is that a laser shoots a beam but a ladar will shoot a beam and it comes back,” explained Mike Jonez, test officer for Aviation Systems Branch. “The time it takes to come back, determines the distance of how far away something is.”  He went on to explain that the sensor has a laser beam that pulses. Every time it sends out a pulse, it reflects off something and it comes back, and that pulse is measured and plotted on a screen. This happens over three million times a second, allowing testers to build an image in real-time.

In the early planning phase of the test mission, the test sites were mapped with aerial ladar to build a geographical database. High definition photography was taken of the obstacles and structures at each test site. The collected data was used to recreate the test sites in a full dome flight simulator.

“We were able to map the entire area within one centimeter of accuracy,” said Jonez.  Pilots from the Air Force, Army, Navy, and Marine Corps were selected to fly the system in the simulator months before they would fly in actual brownout conditions at YPG. This provided valuable feedback that allowed engineers to incorporate design changes before the system was tested.  It also allowed the pilots to gain experience flying the system and becoming familiar with the test sites.

This is a brief explanation of how the system works. As the aircraft approaches the landing zone, the 3D-LZ system maps the area rapidly, building an image for the pilots so they can view the terrain on a monitor located in the cockpit. The imagery is of the ground below them and allows pilots to “see” obstacles during brown out conditions, as if watching a video game.

Jonez worked closely with personnel at the Joint Experimental Range Complex to prepare the facilities and dust courses.  In addition, he orchestrated support from Pyramid Services heavy equipment operators, who plowed the course several times.

The terrain was kept six-inches deep at a powdery consistency, often referred to as “moon dust.” This gave test pilots the worst case scenario of flying into extreme dusty conditions.

Testing a system this sophisticated could not go unnoticed without demonstrating it to individuals who play an important role in funding programs for the improvement and development of sensor/ladar technology. In late September, members from the Office of the Secretary of Defense and contractors from the sensor/ladar industry were invited to YPG for a one-day demonstration to witness the 3D-LZ system first-hand.

“YPG's obstacle course, referred to as the 'Oasis LZ', has become nationally recognized as the place to test this type of technology,” said Jonez. “If anyone wants credibility with their systems, they're required to come here to test them. We offer life-like scenarios and the terrain is perfect for pilots facing similar conditions on and off the battlefield.”

Throughout the test, evaluation pilots completed multiple touchdowns creating giant dust clouds and flying over small obstacles used for detection. Obstacles included the usage of rebar, rocks, fence posts, berms, ditches, cinder blocks, and crates.  In addition, sling load hook-up operations were simulated in light and heavy dust conditions using an artillery piece and a High-Mobility Multi-purpose Wheeled Vehicle.

The test aircraft was modified with a nose mount to accept the ladar. The ladar horizontally scanned and vertically moved to provide a 60 degree azimuth and 30 degree elevation field-of-view.   The ladar could distinguish hard target returns from dust returns with each pulse, providing dust-free terrain and obstacle data during approach, landing and departure.    

“This test provided critical aircraft guidance and control information, including horizontal and vertical speed guidance which improved pilot performance and overall, reduced the workload,” said Jonez. “The beauty of this system is once the brown-out engulfs the airplane and you can no longer see trees, the ground or telephone poles, and the pilot wants to land, the ladar has already mapped out the images. The pilot is able to see through the dust even though he or she can't see out the windshield. All they have to do is look at the display.”

Next year, YPG will host additional programs to continually improve laser/sensor systems. Jonez is working on a similar future test plan for the Navy.

Mary F. Flores writes for the Outpost, the onbase newspaper at Yuma Proving Ground.