USA — As wildfires become more prevalent and ferocious, many in the fire service are looking for better ways to battle wildland blazes. One factor that is almost universally accepted is that the vast majority of fires diminish in severity overnight, when temperatures decline, humidity increases, and winds die down. As a result, a few fire agencies have embraced Night Vision Goggle (NVG) use by their aerial firefighters. This series of articles will examine where this innovation stands now and what might be coming in the future.
NVG can trace its roots to the Second World War, when both the Germans and the U.S. deployed a few dozen Generation 0 night-vision systems toward the end of that conflict. But it wasnt until the U.S. became involved in the Vietnam War that such devices came into more frequent use. From these early Generation 1 units (which required at least some small illumination, like moonlight, to work), more robust units (Generation 2) came into use during the first Gulf War and were a marked improvement over the earlier types. By the beginning of the 21st century, an even better family of devices, known as Generation 3, were available, but are being superseded by the latest military models, variously known as Generation 3+ or Generation 4 devices that are much lighter, have better optical characteristics, and greater longevity than previous generations.
In parallel with the militarys use of NVG in warfighting, firefighting agencies have also experimented with such technology. In 1973, Congress approved special funds for the USDA Forest Service (USFS) to investigate new techniques that would reduce the severe wildfire threat that existed nationwide, said Dennis Hulbert, former USFS Regional Aviation Officer for Region 5 and one of those involved in shepherding this new technology along in that agency. A project was initiated called Helicopter Night Operations and assigned to the San Dimas Equipment Development Center.
But USFS wasnt the only agency conducting experiments. Los Angeles County Fire Department, in conjunction with San Dimas, jumped in as well. On June 16, 1974, the first night water drops were made on a wildfire on the Angeles National Forest with Los Angeles County Fire Departments Bell 204B helicopter, equipped with a fixed tank, Hulbert continued. In 1976, the USFS had its first NVG helicopter, a Bell 212 stationed at Rose Valley Helibase on the Los Padres National Forest, and in 1977, a second Bell 212 NVG ship was stationed at Tanbark Heliport on the Angeles National Forest.
There were a few problems, however, with the first deployments. Generation 2 NVGs were in use and they had limited functionality; narrow 40° field of view, visual acuity equal to 20-50 vision, full face design that prevented looking at flight instruments, susceptibility to blooming (loss of visual image) when confronted with sudden high lighting or reflected glare on the windscreens, said Hulbert.
Not long after these programs were implemented, a mid-air collision nearly stopped them in their tracks. In 1977, an L.A. County Fire helicopter and the USFS Rose Valley helicopter collided while inbound to a heliport on the Angeles National Forest, recalls Hulbert. Both helicopters were operating with NVGs, and one pilot perished while others were critically injured.
Although L.A. County Fire suspended their program, USFS did not at first. From 1978 through 1983, USFS operated the two NVG ships, explained Hulbert. However, due to costs and limited use, they discontinued the NVG program in 2005.
With the dawn of a new century, Los Angeles County Fire treaded carefully back into NVG use. They started back up in 2001 with limited use and returned to a working NVG program in 2005, said Hulbert. Other city/county fire agencies have also pursued NVG as well see later on in the article.
Nevertheless, USFS did not, and still imposes restrictions on night-flying helicopters over areas administered by that agency. Although there was a tremendous uproar in Southern California after 2009s deadly Station Fire, in which two Los Angeles County Fire Department firefighters were killed, the USFS is still restricting their involvement with NVG to paper studies and probably wont be venturing into that arena again any time soon.
CAL FIRE, Californias state firefighting agency, also looks unlikely to pursue NVG flights in the foreseeable future despite an attempt by Governor Schwarzenegger in 2008 to fund 11 NVG-equipped Blackhawk helicopters for use by CAL FIRE. With current funding cutbacks in the amount of $30 million for that agency, the chances of equipping any aircraft in the state inventory with goggles that cost over $11,000 per set (not to mention the cost of training personnel to use them) is fairly unlikely.
There are two schools of thought on how to load up with suppressant to fight fires at night: hover-fill and ground-fill. With ground-fill, the aircraft lands and is reloaded with suppressant (which can be water, foam, retardant, or gelled water) before taking off to drop on the fire. With hover-fill, the aircraft uses a snorkel extending from the tank to reload from a source, before heading to the fire. Engine crews assist with ground-fills by hooking their fire hose to an adapter, which attaches to the helicopters tank once the aircraft has landed. The rotor is spinning overhead during the fill-up, so the aircraft can quickly take off after the tank is filled.
According to some pilots, it takes less time to do a hover-fill, and typically less personnel, especially if its a water source like a golf course pond or aqueduct, but the risk factor goes up by doing this at night. Pilots complain of a white-out effect from water vapor stirred up by the helicopters rotor wash, especially over large bodies of water, and some have even reported mud on the windscreen from dust mixing with water vapor and sticking to the glass.
Likewise, there are two schools of thought on hoist rescues: traditional hoist and European style. With the traditional method, the aircraft hovers directly over the target while lifting and lowering personnel. European style is where the aircraft moves slowly forward while lowering the air medic, then hovers only during the last 10 feet of the medics descent. The advantages to the European method are twofold: less danger to those on the hoist or the ground if an engine failure occurs and less tendency for the people on the hoist to be spun around by the rotor wash.
Currently, three fire agencies in Southern California use NVG: Los Angeles County Fire Department, San Diego Fire-Rescue Department, and Orange County Fire Authority. These agencies use Generation 3 aviator goggles (typically designated as AN/AVS 9 nicknamed Anvis 9) and will be examined in more detail in the second installment of this series.