Apr 20 2012

Aerial Firefighting Technology – Why Shutdown at Sundown? Posted 12 years 15 days ago ago by Admin

By Michael Archer

Photos by Mike Katz

Night Vision Goggles may conjure up thoughts of elite Special Forces units going into battle in the dead of night, but they also have found a use in nighttime helicopter operations. A number of fire departments and agencies have employed these devices to allow them to attack wildfires at night and to perform difficult night rescues that would be foolhardy otherwise. So how did this cutting-edge technology first see the light of day, and what does the future hold?

 

A Brief History Of NVG

Night Vision Goggles were first employed by both the Germans and the US in World War II. A few dozen “Generation 0” night-vision systems were in use towards the end of that conflict. It wasn’t until the US became involved in the Vietnam War, however, that such devices came into more frequent use. These early “Generation 1” units (which required at least some small illumination, like moonlight, to work) led to more robust units (“Generation 2”) which came into use during the Gulf War in 1991 and were a great improvement over the earlier generations. At the dawn of the 21^st century, “Generation 3” NVG made its debut, but is now being superseded by the latest military models, variously known as “Generation 3+” or “Generation 4” – lighter units that have better optical characteristics and greater longevity than previous models.

 

Helicopter Night Operations

It has long been known that wildfires “lay down” at night, becoming more quiescent as temperatures drop and humidity increases. Unfortunately, air operations on wildfires all but cease as nightfall approaches. State and federal restrictions require that aerial firefighters land 30 minutes before sunset and remain grounded until 30 minutes after sunrise.

 

Some fire agencies, however, are not satisfied with this situation and have explored how to better fight fires at night. Night Vision Goggles (NVG) offer the best hope not only of fighting fires, but also allowing night rescue operations as well. 

 

As the military continued improving NVG for combat, firefighting agencies also began experimenting with NVG. In 1973, Congress approved special funds for the USDA Forest Service (USFS) to investigate new techniques which would reduce the severe wildfire threat that existed nationwide. A project was initiated called ‘Helicopter Night Operations’ and assigned to the San Dimas Equipment Development Center. 

 

At the same time, Los Angeles County Fire Department began experimenting with NVG. On June 16, 1974, the first night water drops were made on a wildfire on the Angeles National Forest with Los Angeles County Fire Department’s Bell 204B helicopter, equipped with a suppressant tank. 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 aircraft was stationed at Tanbark Heliport on the Angeles National Forest.

 

These NVG units, however, were less than optimal. 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 bright lighting or reflected glare on the windscreens.

 

After a promising beginning, however, things went bad in a hurry. In 1977, an LA County Fire helicopter and the USFS Rose Valley helicopter collided while inbound to a heliport on the Angeles National Forest. Both helicopters were operating with NVGs, and one pilot perished while others were critically injured.

 

Even though LA County Fire Department suspended their program immediately, USFS did not at first. From 1978 through 1983, USFS operated the two NVG helicopters. However, due to costs and limited use they discontinued the NVG program in 2005.

 

Round Two

At the dawn of the 21^st century, Los Angeles County Fire Department slowly restarted their NVG program. They started back up in 2001 with limited use and returned to a working NVG program in 2005. 

 

However, USFS did not, and still restricts night-flying helicopter activity over federal land. Despite the uproar over the lack of nighttime aerial firefighting during 2009’s deadly Station Fire, in which two Los Angeles County Fire Department firefighters died, US Forest Service continues to limit federal involvement with NVG to paper studies and shows little inclination to employ NVG in aerial firefighting in the foreseeable future.

 

In 2008, California’s governor announced funding for 11 Blackhawk helicopters for CAL FIRE, the state firefighting agency. These aircraft were intended to be equipped with NVG, however with current funding cutbacks, the chances of retrofitting any state aircraft with NVG-friendly lighting is fairly unlikely.

 

Night Operations

There is a great reluctance by city/county fire agencies to pursue nighttime dipping operations over bodies of water, even with NVG. Pilots complain of a ‘white-out’ effect from water vapor stirred up by the helicopter’s 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.

 

As a result, current standard practice is to land and do a ground fill, where fire hoses are attached to a helicopter’s drop tank for the purpose of refilling between drops. This is labor intensive, since a ground crew has to perform the operation while the flight crew remains on the idling helicopter, but pilots pretty much universally agree that it is the safest way to do things. As soon as the load is completed, the helicopter can lift off and return to the fray.

 

Insofar as hoist rescues are concerned, there are two schools of thought: traditional hoist and European style. The aircraft hovers directly over the target in a traditional hoist operation while lifting and lowering personnel. In European style, the aircraft moves slowly forward while lowering the medic, then hovers during the last 10’ of the medic’s descent. The European method has two main advantages: less danger to those on the hoist or the ground if an engine failure occurs; and a reduced tendency for the people on the hoist to be spun around by the rotor wash.

 

Currently, there are three fire agencies in Southern California which 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”). We now take a brief look at what their experience and policies entail for effective (and safe) use of NVG.

 

Los Angeles County Fire Department

Los Angeles County Fire Department (LACoFD) is the agency which has been using NVG the longest. With 9 firefighting aircraft, including 3 Firehawks (the firefighting version of the military’s UH-60 Blackhawk) they are also the largest air operation performing aerial firefighting and rescue operations at night.

 

They converted all of their Bell 412s to work with NVG and two of their S-70s came already equipped with NVG-compatible lighting. They completed their initial training in April 2001, although they didn’t initially fight fires at night because they had to get comfortable with the goggles while performing routine night search and rescue operations, as well as Helicopter Emergency Medical Services missions. As a result, when the massive wildfires of 2003 hit Southern California, they didn’t fly any night ops on fires.

 

In 2005 they fought their first fire from the air near Palmdale. At the same time, Generation 3 goggles improved, with better brightness control, which reduces the chances that a pilot will be blinded by bright lights.

 

Currently, they are exploring the possibility of using firefighting foam to extinguish structure fires, or even to pre-treat structures to make them fire resistant during an incident, thus freeing up firefighters on the ground to battle the wildfire rather than performing structure protection.

 

San Diego Fire-Rescue Department

San Diego Fire-Rescue Department (SDFD) deploys a Bell 212HP (Copter 1) and a newer Bell 412 (Copter 2), both capable of  carrying up to 375 gallons, from Montgomery Field, north of the city of San Diego. 

 

Although SDFD operates 24/7, operations slow way down after sunset for safety purposes. They also do hoist rescues and medical transports using NVG. As long as the pilot and crew continue to scan the area for hazards, they feel that the limited viewing area (40° versus 200° for unaided vision) is still enough to operate the aircraft safely. They can also look under the goggles when necessary to check controls and avionics, if necessary.

 

Being prepared for night ops, even away from base, is also important, so they keep the goggles with the aircraft at all times, just in case.

Orange County Fire Authority

Orange County Fire Authority (OCFA) currently flies two Bell 412 aircraft, and has two older UH-1 helicopters in reserve. They operate out of Fullerton Municipal Airport. They don’t operate on a 24-hour basis as of yet, but hope to in the future.

 

As with LA County Fire Department and San Diego Fire-Rescue Department, OCFA operations slow down after nightfall and they, too, only do ground-fill firefighting operations after dark for safety reasons.

 

NVG Generation 4

The military is experimenting with Generation 4 NVG and with Panoramic NVG, which incorporates four vision tubes instead of the standard two tubes, broadening the pilot’s view from 40° up to 95°. It is hoped that these improvements will reduce crew fatigue, while also providing sharper images in all light conditions.

 

Perhaps public pressure over the damage done by wildfires after dark (such as Southern California’s Station Fire) will finally persuade US Forest Service to venture back into night ops. If so, they will find a landscape radically transformed from the one they left behind in the 1980’s.

 

At the same time, private contractors are entering the NVG arena, like Oregon-based Erickson Air-Crane, whose aircraft fight wildfires in many parts of the US, as well as overseas. Being able to hit a fire at night, after dark, when it is laying down due to increased humidity and decreased temperatures offers the best opportunity to quench fires more effectively than day operations. But the price tag ($30,000 to outfit the cockpit, $11,000 apiece for NVG Generation 3 goggles) is a bit high for small and medium contractors, so the switchover from exclusively day to day/night operations may take some time, not to mention a better economy.

 

NVG has come a long way since World War II. And with the increase in number and ferocity of wildfires, the need to battle blazes after dark, when they are more vulnerable, has a growing urgency. Of equal importance, other nighttime helicopter operations, such as search and rescue, Mercy Flights, and hoist rescue operations present an opportunity for private helicopter contractors to broaden their business. Who knows how this could transform the industry in another few years?