Tuesday, September 1, 2009
Night Vision Goggle Training: Civilian vs. Military
Options abound for training in the use of night vision goggles. Similarities and stark differences exist between the civilian and military approaches. Rotor & Wing takes a comprehensive look at those options, similarities and differences.
Night vision goggles (NVG) have been used by the military for decades and by civilians for about 10 years. As the number of users-turned-instructors has grown and the technology has improved, training has increased in both breadth and depth.
Rotor & Wing talked with experts at a number of NVG training organizations, including small civilian operations, aircraft manufacturer-sponsored schools, U.S. Army NVG pilot training, and USAF combat search and rescue (CSAR) mission training. Although these groups differ radically, much of their initial NVG training is similar.
In fact, in some areas military night training is less aggressive than the civilian equivalent. Neither Army instructors at Fort Rucker, Ala., nor USAF instructors of aspiring CSAR pilots of HH-60G Pave Hawk helicopters, teach autorotations to the ground under goggles, whereas this is a standard part of the curriculum in Bell Helicopter, American Eurocopter and Night Flight Concepts (NFC) programs. The Army accounts it an unnecessary risk, and the Air Force wants to preserve a limited resource — the small of number of CSAR training helicopters. In general, however, military aviators receive more hours of NVG training (independent of mission training) and are taught at much lower altitudes with more difficult tasks, such as nap-of-the-earth (NOE) flying for the Army and night aerial refueling for the Air Force CSAR students. The military also puts goggles on crewmembers and stresses crew resource management (CRM) more intensely.
Much, however, is similar between the two worlds. Instructors everywhere emphasize the importance of the helmet fit and goggle focus. "We stress that you don’t fly in pain," says Del Livingston, vice president of flight operations, customer training and aviation safety for American Eurocopter, which runs a flight school in Grand Prairie, Texas. The weight of the helmet, goggles and counterweight can be a source of pain for those new to the equipment. If the fit is imperfect, helicopter vibration can create what feel like "hot spots" on the scalp. If this occurs, training is temporarily halted while adjustments are made.
Focusing the goggles is also a crucial skill. Students are "not used to looking at little green and black images right in front of their eyes — they don’t know what to expect," says Marty Wright, chief flight instructor at the Bell Helicopter Training Academy in Fort Worth, Texas. Focusing is a gradual process, and young aviators sometimes have the goggles only partially focused, so that their eyes are making up for a portion of the focus, he noes. When the eyes tire, the focus degrades. "So you have to teach them about refocusing on a regular basis." It takes about three nights of using the equipment to figure out what works best for them and "how good a picture they’re supposed to be seeing" through the goggles, he says.
All of the schools, civilian and military, teach pilots to recognize and compensate for the limitations of the goggles, such as the field of view (40 degrees vs. the normal 220 degrees), two-dimensional image, monochromatic coloring in shades of green, and degraded ability to perceive depth and estimate distance.
Perhaps the greatest challenge for students is to learn "to fly in a three-dimensional world with a two-dimensional image," says Chief Warrant Officer Rich McHenry, head of the Night Vision Devices Branch of the Army’s 110th Aviation Brigade at Fort Rucker. Pilots compensate for the drastically curtailed field of view by developing a scanning technique which requires them to move their heads as well as their eyes to pick up visual cues. Scanning is the most difficult thing for students to learn, according to Brandon Briggs, Eurocopter’s assistant chief instructor pilot.
Students also have to learn to look under the goggles to scan the instruments, points out John Wardle, director of training for Night Flight Concepts, a training company in Port St. Lucie, Fla. If they try to look at the instruments through the goggles, "all they would see is a blurry image because the NVG is focused to an infinity distance outside of the aircraft," he explains. NFC has partnered with Palm Beach Helicopters and others to expand its business.
Pilots are taught "monocular cues" such as geometric perspective, aerial perspective, retinal image size and motion parallax. "The image is flattened, but because you’re using monocular cues, your brain puts it into a three-dimensional picture," explains Capt. John Brunner. He is an instructor pilot and senior evaluator with the USAF’s 58th Special Operations Wing at Kirtland AFB, N.M., which trains both special operations and CSAR pilots.
Retinal image size allows viewers to associate distance with size. For example, an aircraft decreasing in size appears to be moving away. But size can be confusing, as Wardle points out. What looks like a Cessna nearby may actually be a B747 farther away. If you’re flying a traffic pattern at a local airport near a larger airport, this can be dangerous. The ability to look around the goggles helps to correct for this illusion. Things also appear to be closer under the goggles, Wardle says. Because of the two-dimensionality of the goggle view and the brightness of the lights, it’s possible to confuse the planet Venus for an aircraft.
Motion parallax means the farther you are away from objects, the slower they appear to be moving; but the nearer you get to them, the faster they seem to be moving. As a pilot descends and decelerates, he has to keep scanning from side to side to make sure that the trees are going by at a constant rate, Wardle explains. Experience and maintaining currency are key in overcoming the inherent limitations of the NVGs, he says. Each of the visual issues and the countermeasures to them are taught to students from day one.
Civilian students typically get eight hours of ground school and six hours of flight instruction spread across several days. Students are already licensed pilots, many of them instrument-rated. Military pilots spend a lot longer in the schoolhouse and the aircraft, partly because they’re getting mission training as well as basic instruction on the goggles.
Schools use a building block approach, progressing gradually from simple to more complex concepts and maneuvers. The first night at American Eurocopter’s academy includes basic exercises such as traffic patterns and working on depth perception at a hover. "We spend a lot of time the first night getting used to this world of 2D," says Paul Osterman, manager of simulation and standardization with Eurocopter. After about 45 minutes, students are asked to flip their goggles up and start shooting a normal approach. Their "extreme discomfort" demonstrates to them that it has taken less than an hour to get completely accustomed to the devices, Osterman says. Students then flip down and complete the flight with the goggles.
Successive nights at Eurocopter’s and other schools include confined area operations, slope operations, obstacle identification and avoidance, and emergency procedures. Eurocopter includes hydraulic failure, engine failure, spatial disorientation and NVG failure among its emergency procedures. Although pilot evaluation is progressive, there is a proficiency flight evaluation on the final night.
Bell Helicopter teaches a similar list of maneuvers. It emphasizes that 90 percent of NVG flight time occurs with only natural illumination — the moon and stars. Only 10 percent of flight training is conducted in an airport environment with ground lights.
Bell says the hardest things for students are drift control (picking up visual cues) and the sheer foreignness of the goggles. It’s easy for beginners to get lost the first couple of nights, even in their local areas, Wright says. They are used to looking at patterns of lights on the ground and the different colors that make up these patterns. It’s also easy to get "target fixation," when the pilot just focuses on what he sees through the NVGs. "You start teaching them how to use [the NVGs] as an aid to what they’re doing, not solely what they’re doing." Students learn to "look around the goggles, over them, under them, and to the sides" to see the light patterns and help judge weather — illumination permitting.
Smaller schools like Longhorn Helicopters, Denton, Texas, offer similar curriculums at what they say are much lower prices. Longhorn, which is partnering with Aero Dynamix, charges $7,600 for its initial NVG course in the B206 and $3,500 for the initial course in the Sikorsky/Schweizer 300C. That’s well below the fees charged by the aircraft manufacturer schools, says Dale Williamson, director of operations.
U.S. Army student pilots at Fort Rucker take initial NVG qualification training in the OH-58D, AH-64, UH-60 or the CH-47. They receive six hours of ground school — three hours on goggle operations and three on night vision planning and terrain interpretation, plus two hours on head-up displays and how they couple with the goggles. In flight school each receives 17 to 20 hours of NVG training.
The first two nights consist of unaided flight. Afterwards students progress through a "structured maneuver list" outlined in a flight training guide, according to Chief Warrant Officer Ronald McKinstry, chief of standards for the 110th Aviation Brigade. On the final night, there is a 1.5-hour evaluation ride to determine NVG proficiency. Among the more complex maneuvers are single-engine landings, confined area approaches and nap-of-the-earth flight at of 25 feet or less above the ground.
Instructors at Fort Rucker use virtual terrain boards (see sidebar page 50) and train students at 14 to 15 stage fields — remote sites with about six short runways, or lanes, a control tower and crash rescue facilities.
USAF aviators aiming to specialize in combat search and rescue operations have already passed through the initial goggle training that the Air Force’s 23rd Flight Training Detachment conducts at Fort Rucker on UH-1Hs and TH-1s. This includes about 7.5 hours of simulated NVG training with academics and a terrain board, as well as 10 hours of NVG flight training. The students then proceed to Kirtland AFB for initial NVG qualification on mission aircraft.
On top of the 17.5 hours of NVG training at Fort Rucker, the Air Force CSAR students transitioning to HH-60G Pave Hawks receive another 35 hours of NVG training. Lockheed Martin handles the classroom and simulator side of training. Students receive 10 hours of classroom and computer-based instruction, as well as 7.5 or more hours of simulator training from the contractor on aided night flying.
Night flight training on the HH-60G is conducted by military instructors. There are five flights — 12.5 hours or more — as well as about five hours of ground training. Nap-of-the-earth flying is not taught, but students fly at 50 to 100 feet in contour and low-level flight, Brunner says. The two single-ship and three multi-ship flights include an air refueling check ride and a final mission check ride that typically lasts three hours. When students have passed the course, they are qualified to fly combat SAR missions, but only as copilots. They’ll need at least 100 hours of flight time, including 50 hours on the goggles, at their units before they can qualify for the aircraft commander’s course and advance to HH-60G pilot status, according to Brunner.
Another difference between military and civilian training is the former’s more intense focus on crew resource management. HH-60G crew members wear goggles. Brunner describes the crews as "fused." Pilots, gunners and flight engineers are trained together in the initial course. The 58th uses a "triangular" concept for the approach phase, where the pilot-not-flying calls out altitude and ground speed, while the flight engineer and gunner call out rates of closure and clear the aircraft to the ground. The pilot will scan for the approach, but all of the crew are trained to cooperate in these high-workload operations. "Under our NVG regulations, we have to have all four crew positions filled to fly low-level [below 500 feet]," Brunner adds.
Search and rescue training, at the commander level, also involves learning how to do detailed mission planning on the fly. Combat SAR is very time-sensitive, Brunner stresses. The HH-60G is equipped with computer-based mission planning tools, including mission mapping and beyond-the-horizon mapping data. Pave Hawks also are equipped with a "fused" inertial navigation, GPS and Doppler navigation package, as well as a color weather radar.
Perhaps the most difficult task for the Air Force students to learn is aerial refueling, Brunner says. The procedure involves joining with the tanker, flying in formation with the tanker, getting into refueling position and plugging a six-inch probe into a 23-inch basket at speeds of up to 115 knots "in all sorts of weather."
Military and civilian night vision goggle (NVG) schools use computer-based training (CBT) as part of ground instruction. Avstar Media, Addison, Texas, specializes in CBT, and NVG is one of its many offerings.
"We cater to people who want to do [NVG classroom training] in house, says Dick Gilson, vice president. The NVG course, which is hosted on Avstar’s server, takes approximately five hours to complete and includes subjects such as the equipment, its limitations, the physiology of the eye, and operations. Typical users include emergency medical services (EMS) and law enforcement entities.
CBT has many advantages vs. classroom training, Gilson contends. It’s low-priced, considering that there’s a recession going on and "training is frequently just below magazine subscriptions in priority," he says. What’s more, students progress at their optimal learning rates rather than at the rate of the slowest class member. Each lesson is designed to take 15 to 20 minutes, the best length according to educational psychologists.
Official approval comes by way of the customers, who administer their own courses and get the FAA’s blessing. The same material, which is reviewed and updated on a regular basis, is used in recurrent training.
The system generates a different test for each student, something that’s not always done in stand-up training, Gilson says.
Virtual Terrain Board
The virtual terrain board (VTB) is a system that generates terrain scenes showing the effects of different night illumination. It is designed as a classroom training aid, using about a dozen high-fidelity databases of satellite imagery and photography, says Stephen Hatley, president of Night Readiness, the Chandler, Ariz., designer of VTBs.
The company provides scenes that "stimulate," or drive the goggles, so that students wearing goggles can see what it’s like to use the equipment. It can present "simulated" goggle scenes as well. Stimulation is typically used in ab initio training, and simulation in refresher training, Hatley says. His primary customer is the U.S. military.
The current version of the software can vary terrain, percent illumination, and moon elevation and azimuth, among other things. Customized databases are provided on demand.
Although the current system focuses on the effects of varying illumination on terrain, the next release, expected in October, will add fly-through capability, as well as some weather effects. The whole system, including all hardware, software, peripherals, training on how to use it, a syllabus and two years of hardware support, are priced at less than $100,000, Hatley notes.
NVG Flying 101
Palm Beach Helicopters offers an entry-level night vision goggle (NVG) course taught in partnership with Night Flight Concepts (NFC), a company that specializes in night vision pilot training. Rotor & Wing was offered a chance to train with them and experience this advanced technology.
Randy Rowles, one of NFC’s vice presidents and an 11,000-hr helicopter pilot with ATP and CFII ratings, as well as an FAA rotorcraft examiner, escorted me into a classroom where NFC’s one-of-a-kind projection system was at the ready. It allowed me to look at nighttime scenes on a specially made screen that changed accordingly when I looked at them through the NVGs. "This is exactly how wires, transmission towers and other obstacles will look in the real world," said Rowles.
After classroom instruction on the intricacies of NVG use and care, it was time to go to the school’s outdoor classroom: the Florida Everglades.
Flying with the helmet-mounted, mini binocular-size NVG goggles flipped down in front of my eyes transformed the black void of the Everglades into a bright, green-tinted world that revealed hundreds of ponds, clumps of vegetation and rotor blade-eating water management gear. Had we lost our engine, the NVGs would have let me see a variety of potential landing zones that I would not have seen otherwise. (That’s a really good thing in the area’s shallow, alligator-patrolled waters!)
What I didn’t like was the reduced field of view. Looking through NVGs is like looking at the world through two short pieces of pipe: Seeing things directly in front of you is easy, but things around the periphery require a conscious readjustment of your eyes. It was particularly disquieting when I wanted to scan my instruments.
"Don’t worry about looking at the instruments through the goggles," said Rowles. "Just look down below the eyepieces, see what you need to see, then get back outside." Sure enough, looking below the eyepieces — or around them, for that matter — took the NVGs out of play when I wanted to see something that didn’t need to be enhanced. Even if I needed to see directly in front of the aircraft without using the goggles, the procedure was simple. All I had to do was turn my head slightly to one side and look around the tubes. It also serves as an emergency procedure if the NVGs fail and there isn’t time to flip them up out of the way.
While out on our training sortie, I tried autorotations, platform landings and hovering autos. As Rowles promised, those maneuvers were not very difficult to perform, once I learned how to scan properly while wearing the goggles.
Unlike the first-generation night vision goggles of the early 1970s, coming out from under today’s NVGs did not leave me with night blindness. The only remnant of goggle use was several minutes of having bright white lights appear slightly brown. Otherwise, I found no huge disadvantages to NVGs.
In fact, they had a manageable learning curve and really enhanced night flight safety. — By Ernie Stephens, Editor-at-Large