Quenching the Flames


10th January 2020
Thomas Withington

Once again, aerial firefighting has played a vital part in combating wildfires in California, with an armada of aircraft leading the efforts to douse the flames.

It has been another busy year for aerial firefighting in California. The statistics speak for themselves: The US Forest Service and the California Department of Forestry and Fire Protection, better known as Cal Fire, have responded to over 6,400 fires as of the time of writing (late November 2019). By early November, fires had devastated 101,313 hectares (250,349) acres of land. 36 of these fires have consumed in excess of 400 hectares (1,000 acres) and the fire season has caused ten fatalities; eight of which were firefighters. 

One of Neptune Aviaton’s BAE-146 aircraft is seen here delivering fire retardant during the Buffalo Mountain fire in Summit County, Colorado in 2018.

The largest conflagration so far has been the Kincade Fire in Sonoma County, on the northern Pacific coast of California. This has devastated an estimated 31,460 hectares (77,758 acres) since the conflagration started on 23 October before it was finally contained on 6 November. Just as well that CalFire boasts what is reportedly the largest aerial firefighting fleet in the world with 50 aircraft at its disposal strategically placed at bases around the state. This is vital to ensure that the aircraft can arrive at the scene within 20 minutes of the fire being reported. Like any conflagrations wildfires can often be nipped in the bud to prevent wider destruction if a timely response is made. This is approach is known as Initial Massive Attack: “Get out there early, and don’t let the fire get out of control,” remarks Christian Bergeron, director of sales at Viking Air.

During 2019’s fire season in California, a varied aerial firefighting fleet performed a diverse array of roles. For example Grumman S-2T Tracker radial engine planes, originally used by the US Navy from 1954, have since enjoyed an active retirement as tankers. Other old-timers in the form of North American/Rockwell OV-10A Bronco turboprop counter-insurgency aircraft are extensively used by Cal Fire as observation aircraft while Bell UH-1H Huey light utility helicopters, arguably one of the signature aircraft of the US involvement in the Vietnam War between 1965 and 1975, haul buckets of fire retardant and water to help stop fires spreading, and to quench them once they start. Old though the aircraft maybe, they are extensively customised for the tasks they perform. Water and retardant delivery systems, are often accompanied by rescue winches on the helicopters, with some rotorcraft such as the UH-1Hs even receiving new rotor blades and structural improvements. The strategy to fight fires from the air is deceptively simple: ring-fence the fire with retardant to stop it spreading and then hit the fire with water. Yet the hot air rising from the flames makes for challenging and sometimes dangerous conditions as the aircraft can be violently buffeted when performing their missions.

During the Kincade Fire, aerial firefighting played a key role in stopping an already severe fire from becoming much worse. The California Department of Forestry and Fire Protection, popularly known as Cal Fire, amassed an armada of aircraft to tackle the blaze. Fixed wing assets included 21 S-2T Trackers, plus a single Hawker Beechcraft A-200CT and 14 OV-10A turboprop observation aircraft. Rotary wing assets included ten UH-1Hs. A further 17 helicopters from private sector aerial firefighting operators reinforced this total, along with Global SuperTanker’s mammoth Boeing 747-400 converted airliner capable of dispersing 17,500 US gallons (66,244 litres) of fire retardant per flight. The 747-400 deployed to McClellan airbase in northern California to be close to the fire. This aircraft is used to deliver fire retardant, and can disgorge the retardant at altitudes of between 400 feet/ft to (121.9 metres/m) to 800ft (243.8m) at speeds of 140 knots (260 kilometres-per-hour). The aircraft is capable of delivering retardant over a 46m (150ft) wide swathe 4,800m (three miles) long. 

Ill Winds

All these aircraft plied their trade in challenging conditions. The same Diablo wind which helped to fan the flames of the Kincade Fire with gusts of up to 69 knots (127.8 kilometres per hour) caused challenging flying conditions for the planes and helicopters sent to tackle the blaze. Neptune Aviation has been heavily involved in the aerial firefighting effort in California. Its’ chief pilot Thomas Loehde observed that “fires can be fast moving due to abundant fuel sources, high winds, and hot air temperatures.”

Mr. Loehde disclosed that the firm had deployed six of its BAE Systems BAE-146 converted turbofan airliners to support aerial firefighting operations in the state this year: “Two of the aircraft flew under the direction of the United States Forest Service,” Mr. Loehde said, while ‘”four of the aircraft were deployed to assist the efforts of Cal Fire to help combat fires throughout the state.” The efforts of these six aircraft amounted to the delivery of “more than 492,000 gallons (1.8 million litres) of retardant in California,” dispersed over 164 sorties between 1 October and 1 November. Mr. Loehde continued that the management of these sorties was performed in conjunction with the US Forest Service and Cal Fire: “Neptune manages the aircraft, pilots, and mechanical crews. The forest service and Cal Fire direct the aircraft to the fires. These agencies decide where and when a Neptune aircraft will be deployed to drop retardant.”

For Mr. Loehde and his colleagues, California provided a highly challenging environment in which to fly, not only because of the local meteorology, as discussed above: “the geography requires constant vigilance from the flight crew: the canyons, mountains, and ridgelines of California create an environment where aircraft manoeuvrability is extremely important. Finally, aerial firefighting operations in California generally take place in urban wildland interface areas with high risk factors for residents and ground firefighting crews.” The company’s BAE-146 does provide some benefits in this regard: “Neptune’s fleet of BAE-146 aircraft offer outstanding manoeuvrability, excellent short field performance, and reliable slow flight characteristics.” For example the BAE-146-300 variant of the aircraft has a take-off and landing run of 1,535m (5,038ft) and 1,270m (4,170ft) respectively, with these being shorter for smaller models of the aircraft.

Neptune was not the only company which deployed BAE-146 series aircraft to help fight the fires in California. Aero-Flite used the Avro RJ-85 variant of this plane, of which it deployed six, alongside four Viking CL-415 amphibians. Mike Lynn, Aero-Flite’s director of flight operations, disclosed that the RJ-85s had been used to deliver retardant while the CL-415s were used to drop water: “We provide close support for the firefighters. We very rarely put fires out by using aircraft, so we are a tool for the guys and girls on the ground who are fighting the fires,” Mr. Lynn continued. For him and his colleagues, aerial firefighting is more than ‘just a job’: “We take fighting fires extremely seriously as people can lose their lives, get injured and lose their homes.”

Once again the CL-415 proved its worth as a highly capable platform thanks to its amphibious capabilities: “These aircraft can scoop water off a water source such as a lake, mix it with foam in the aircraft’s tanks and then dump it onto the fire,” notes Mr. Bergeron. This increases the sortie rate compared to conventional aircraft which need to return to an airfield to be refilled with water or retardant: “Land based aircraft have to be refilled which can sometimes take over an hour,” he said,  “but the CL-415 can do that cycle in less than ten minutes. This means the aircraft can deliver an enormous amount of water and foam.” This aids the Initial Massive Attack approach Mr. Bergeron described above: “One aircraft can do multiple cycles attacking the fire before it gains strength, and the aircraft can be at a fire within 45 minutes to one hour of detection.”

Regrettably, California will continue to suffer wildfires in the future. That being said the aerial firefighting community is prepared: “Each year, Neptune strives to identity new innovative ways to respond effectively to the ever-changing aerial firefighting environment. While it is too early to predict the major lessons-learned from this year’s efforts in southern California, Neptune will continue to work closely with our partners to identify best practices to efficiently combat wildfires with our aerial firefighting fleet,” Mr. Loehde states. Reflecting on 2019’s fire season in California, Mr. Lynn observed that “it was a long fire season, but fortunately the number of fires and their intensity was not as bad as the years before, but as always we kept our skills sharp. We had to be ready, and we will always be prepared.”