Dancing in the Dark
Night vision goggles can save a pilot's life or, if he hasn't had adequate training, take it.
- By John Croft
- Air & Space magazine, November 2004
USAF/Tech. SGT. Scott Reed
(Page 2 of 5)
Before we cranked up the Bell 407, we preflighted our NVGs, adjusting the independent horizontal and vertical alignments of each tube, testing the electrical connections to the battery pack, and focusing the goggles on light sources and other objects in the waning twilight outside Bell's Fort Worth facility. We took off and buzzed along a river, through some fields and up and over a line of trees, a treacherous route made less stressful by the goggles and by Baxter's knowledge of the area. The pulse-pumping surreal experience made it clear to me that NVGs can lead, or, like a siren's song, lead astray.
"People think they're Superman," says Joe Roberts, chief of the flight instruction branch for the U.S. Army at Fort Rucker, Alabama. "It's like watching TV—the obstacles going by the airplane don't seem real like they do in the daytime." Roberts says this kind of illusion is one good reason why Army warrant officers get an initial 30 hours of NVG training at Fort Rucker, plus an "absolute minimum" of another 10 hours when they get assigned to units in the field.
Education is the tool of choice to counter the Superman syndrome, both in the armed forces and at Bell. The company's week-long NVG course, created by Baxter and C. "Mac" McMillian, Bell's chief flight instructor, demonstrates to students in the civilian sector both the advantages and the limitations of NVGs. Pilots can take the $8,500 package, which includes six lectures in the classroom and at least 7.5 hours in the air at night in the school's three NVG-equipped helicopters, before they take jobs with police or emergency medical services (EMS) operations. Baxter briefed me on the schoolwork before we flew, describing classroom modules on everything from cockpit lighting to mission planning.
Information in Bell's course is largely drawn from the harsh lessons that the military, particularly the Army, learned when it first put NVGs into aircraft in the 1970s. "They gave them to us and said, ‘Go fly,' " says Roger Anderson, a former Army helicopter pilot who is now a marketing manager with NVG maker ITT Industries.
While archaic by today's standards, the first aviation goggles, called PVS-5s, were quite advanced compared to the IC-16 infrared night scopes, known as Gen 0 (generation zero) technology, that appeared in the field in the 1950s in order to gain the tactical advantages of being able to see an enemy who couldn't see you. Since that time, night vision systems took two paths: Infrared sensors like the IC-16 evolved into forward-looking infrared (FLIR) systems, which include a bulky sensor pod outside the aircraft and an electronics box and display unit inside, while goggles evolved into image intensifiers. FLIRs, while well suited to view details of a target area from a head-up or panel-mounted display, are not good candidates for piloting, partly because the view doesn't follow the pilot's line of sight.
In Vietnam in the 1960s, ground forces used unwieldy Gen 1 image intensifiers called starlight scopes, in which three image intensifier tubes were stacked end to end, like flashlight batteries. Gen 2 came out in the 1970s with the introduction of the microchannel plate, which eliminated the need to stack multiple intensifiers and paved the way for compact helmet-mounted goggles like the PVS-5.
While the technology had improved, inexperience with human factors issues in night vision systems for aviation proved troublesome and often disastrous. Unlike today's NVGs, the PVS-5 clamped onto the pilot's face like a weighty scuba mask. In order to see the instrument panel, crews had to either focus one side of the goggle outside and the other on the instrument panel, or have one pilot focus outside and one inside.
Dutch Fridd, an EMS pilot and the first civilian appointed as an NVG instructor by the Federal Aviation Administration in 1999, began using the full-face PVS-5 in 1978 in Army helicopters. Fridd says crews went out with no guidance on the use of the goggles and no information about their performance in various weather conditions. Some pilots were refusing to fly and others who tried had trouble controlling their helicopters or became ill from spatial disorientation. "During formation takeoffs, you had people flying backwards, sideways," Fridd says. "Others were hitting wires or trees." During his first 40 or 50 hours of PVS-5 flight time, he "absolutely detested it," he says.