Firefighting planes on Aug. 22
Air attack
How California uses dozens of aircraft to battle wildfires
Firefighters have been battling some of the largest fires in California’s history in recent weeks. In total, about 2.2 million acres have been blackened, according to the California Department of Forestry and Fire Protection (Cal Fire).
A fleet of specially equipped firefighting aircraft that can steer or contain a fire’s perimeter help fire crews on the ground. We show here the types of aircraft, from specially converted passenger jets to aircraft that can scoop water from a lake, in action and their specific roles.
Cal Fire has its own fleet of aircraft operating from 12 airfields and 10 helicopter bases across the state that can reach most fires within about 20 minutes. The three main components of the fleet are tactical planes, airtankers and helicopters. All have specific roles but work together as a unit to combat fires.
Tactical aircraft
Monitor fires and direct airtankers and helicopters to critical areas
Helicopters
Can scoop and drop water but can also be used to transport firefighters and equipment
Tankers
Drop fire retardant or water
Tactical aircraft
Monitor fires and direct airtankers and helicopters to critical areas
Helicopters
Can scoop and drop water but can also be used to transport firefighters and equipment
Tankers
Drop fire retardant or water
Helicopters
Can scoop and drop water but can also be used to transport firefighters and equipment
Tactical aircraft
Monitor fires and direct airtankers and helicopters to critical areas
Tankers
Drop fire retardant or water
Tactical aircraft
Monitor fires and direct airtankers and helicopters to critical areas
Helicopters
Can drop water or transport firefighters
Tankers
Drop fire retardant or water
Helicopters
Can scoop and drop water but can also be used to transport firefighters and equipment
Tactical aircraft
Monitor fires and direct airtankers and helicopters to critical areas
Tankers
Drop fire retardant or water
According to Cal Fire’s website, the fleet’s more than 50 planes and helicopters make it the largest department-owned fleet of aerial firefighting equipment in the world. But if extra resources are needed, the department hires additional planes on a contract basis and in extreme conditions, it can request help from the military.
Cal Fire said on August 23 that a total of 95 aircraft were battling the blazes.
Tactical planes
These aircraft are used in aerial command and control roles in fighting wildfires, providing tactical coordination with commanders on the ground and other aircraft in the sky. Most of Cal Fire’s tactical planes are North American Rockwell OV-10 aircraft.
OV-10 “Bronco”
OV-10 “Bronco”
OV-10 “Bronco”
OV-10 “Bronco”
The OV-10 Bronco is a twin-turboprop, multi-mission aircraft that served with the U.S. Navy, Marine Corps and Air Force until the 1990s. Cal Fire obtained 15 of the retired planes from the Department of Defense in 1993 and converted them for fire-fighting.
The map below shows Cal Fire tactical flights around the LNU Lightning complex fires over the course of the day on August 22. Flight path data from FlightRadar24 shows how five OV-10s made flights over the fire, staying in the air for hours.
Active fire edges
Windsor
Circling over the
edge of the fire
Santa Rosa
Active
fire edges
Middletown
Active fire edges
Healdsburg
Circling over the
edge of the fire
Windsor
Circling over the
edge of the fire
St Helena
Santa Rosa
Active
fire edges
Middletown
Active fire edges
Healdsburg
Circling over the
edge of the fire
Windsor
Circling over the
edge of the fire
St Helena
Santa Rosa
Active fires
Circling over
edge of fire
Dozens
of flights
Santa
Rosa
Active
fire edges
Middletown
Active fire edges
Healdsburg
Circling over the
edge of the fire
Windsor
Circling over the
edge of the fire
St Helena
Santa Rosa
The planes circled repeatedly around two active edges of the fires for long periods of time, managing resources and directing crews in the air and on the ground. Unlike air tankers, which need to make repeated short runs to refill with water or fire retardant after a drop, the OV-10s can stay airborne for hours and can also act as lead planes when necessary to guide large tankers into drop zones.
Tanker planes
The workhorse of Cal Fire’s fleet is the Grumman S-2T tanker. The aircraft can hold about 4,500 liters (1,200 gallons) of fire retardant that it can drop in the path of fires. The planes are smaller than many air tankers and can be used in fast initial attacks on fires. The ex-military aircraft were used to track submarines until the 1970s.
Grumman S-2T
Grumman S-2T
Grumman S-2T
Grumman S-2T
The Grumman S-2T has a fill spout in the tail, allowing it to be “hot loaded” with retardant without having to shut off its engines. This means it can be back in the air within minutes. One S-2T can cycle through multiple times this way before it needs to be shut down and refueled.
Reload and return
Flight profile for S2-T tanker on August 22.
Tankers usually reduce altitude
on approach to fire before
dropping retardant
Mission to tackle fire
1,000m
Ground
Time on ground refilling
with fire retardant
7.19pm
Missions
over
5.33 pm
Takeoff
Mission to tackle fire
Tankers usually reduce altitude
on approach to fire before
dropping retardant
1,000m
Ground
5.33 pm
Takeoff
Landing
Time on ground refilling
with fire retardant
7.19pm
Missions over
Tankers usually reduce altitude
on approach to fire before
dropping retardant
Mission to tackle fire
1,000m
Ground
5.33 pm
Takeoff
Landing
Time on ground refilling
with fire retardant
7.19pm
Missions over
Mission to tackle fire
1,000m
Ground
5.33 pm
Takeoff
Time on ground refilling
with fire retardant
7.19pm
Missions
over
The short runs are evident in flight path data, again from August 22 around the LNU Lightning Complex fires. The map shows how the planes repeatedly loop around to the edge of the fire before returning to land at the air base.
Active fire edges
Windsor
Tankers tackling
edge of the fire
Cal Fire air base
Sonoma County Airport
Dozens
of flights
Santa Rosa
Active
fire edges
Middletown
Active fire edges
Healdsburg
Tankers tackling
edge of the fire
Windsor
Tankers tackling
edge of the fire
Cal Fire air base
Sonoma County Airport
Dozens
of flights
Santa Rosa
Active
fire edges
Middletown
Active fire edges
Tankers tackling
edge of the fire
Healdsburg
Windsor
Tankers tackling
edge of the fire
Cal Fire air base
St Helena
Sonoma County Airport
Dozens
of flights
Santa Rosa
Active fires
Tankers
tackling
edge of fire
Cal Fire
air base
Dozens
of flights
Santa
Rosa
Active
fire edges
Middletown
Active fire edges
Tankers tackling
edge of the fire
Healdsburg
Windsor
Tankers tackling
edge of the fire
Cal Fire air base
Sonoma County Airport
St Helena
Dozens
of flights
Santa Rosa
Tankers don’t usually drop retardant directly on the fire itself. Instead, they let it go in front of a fire, directing its course or slowing its advance, and giving ground crews a chance to control or extinguish it. Retardant can also be released to protect homes or important sites and to keep access roads open.
Multiple lines of retardant around a fire at Henry W. Coe State Park,
California, on August 29.
Fire retardant
To city of
Morgan Hill
500 m
Satellite image: Planet Labs
Multiple lines of retardant around a fire at Henry W. Coe State Park, California, on August 29.
Fire retardant
To city of
Morgan Hill
500 m
Satellite image: Planet Labs
Lines of retardant around a fire at
Henry W. Coe State Park, California, on Aug. 29
Retardant
To city of
Morgan Hill
500 m
Satellite image: Planet Labs
Mega Tankers
Cal Fire can also employ contractors to bring in Large Air Tankers (LATs) and Very Large Air Tankers (VLATs) to help suppress major fires. The aircraft are usually passenger jets that have been converted to tankers. Here are some of the tankers that have helped fight the fires in California recently.
McDonnell Douglas DC-10
External water tank
McDonnell Douglas MD-87
External water tank
British Aerospace 146
C-130 “Hercules”
McDonnell Douglas DC-10
External water tank
McDonnell Douglas MD-87
External water tank
British Aerospace 146
C-130 “Hercules”
McDonnell Douglas DC-10
External water tank
McDonnell Douglas MD-87
External water tank
British Aerospace 146
C-130 “Hercules”
DC-10
Water tank
MD-87
Water tank
Bae 146
C-130
The large air tankers can carry a much larger load than the smaller Cal Fire tankers. The diagram below shows how much retardant or water can be dropped by each type of aircraft.
Aircraft capacity
In liters
UH-1H
“Super Huey”
1,200 liters
(buckets)
Grumman
S-2T
4,500
CL-415
“Super Scooper”
6,100
WATER
British
Aerospace 146
11,400
RETARDANT
McDonnell
Douglas MD-87
11,400
C-130
“Hercules”
15,100
McDonnell
Douglas DC-10
35,600
Boeing 747 Supertanker
68,100
Equivalent of over
56 helicopter buckets
Aircraft capacity
In liters
UH-1H
“Super Huey”
1,200 liters
(buckets)
McDonnell
Douglas MD-87
11,400
RETARDANT
WATER
Grumman S-2T
4,500
British
Aerospace 146
11,400
CL-415 “Super Scooper”
6,100
747 carries the
equivalent of over
56 helicopter
buckets
C-130 “Hercules”
15,100
McDonnell
Douglas DC-10
35,600
Boeing 747 Supertanker
68,100
Aircraft capacity
In liters
UH-1H “Super Huey”
helicopter
1,200 liters
(carried in buckets)
McDonnell
Douglas MD-87
11,400
RETARDANT
WATER
Grumman S-2T
4,500
British
Aerospace 146
11,400
CL-415 “Super Scooper”
6,100
747 carries the
equivalent of over
56 helicopter
buckets
C-130 “Hercules”
15,100
McDonnell
Douglas DC-10
35,600
Boeing 747 Supertanker
68,100
Aircraft capacity
In liters
UH-1H
“Super Huey”
1,200 liters
(buckets)
Grumman
S-2T
4,500
CL-415
“Super Scooper”
6,100
British
Aerospace 146
11,400
WATER
RETARDANT
McDonnell
Douglas MD-87
11,400
C-130
“Hercules”
15,100
McDonnell
Douglas DC-10
35,600
Boeing 747 Supertanker
68,100
Equivalent of over
56 helicopter buckets
Cal Fire is also using the 747 supertanker, the largest firefighting aircraft in the world, to battle the current wildfires. The converted Boeing 747, the world’s most easily recognized jetliner, with its humped fuselage and four engines, is currently the only such model in operation.
The aircraft’s pressurized system can dump about 68,000 liters (18,000 gallons) of retardant in a matter of seconds from as low as 60-90 meters (yards) above ground level.
Boeing 747 Supertanker
Retardant
tanks
Discharge
valves
Pressurized
air tanks
Boeing 747 Supertanker
Retardant
tanks
Large retardant
tanks
Discharge
valves
Pressurized
air tanks
Boeing 747 Supertanker
Retardant
tanks
Large retardant
tanks
Discharge
valves
Pressurized
air tanks
Boeing 747 Supertanker
Retardant
tanks
Discharge
valves
Pressurised
air tanks
The 747 supertanker takes around 30 minutes to fill on the ground, longer than some other tankers and much more than the few minutes needed for the S2-T Cal Fire tankers. But the line of retardant that can be delivered to the ground in one run is significantly more effective than that of other tankers.
Guided drops
Some tankers require a “lead” aircraft to guide them in and show exactly where to drop retardant. Some large tankers come with their own lead aircraft and team, or Cal Fire’s tactical OV-10s serve as lead aircraft.
An air tanker is guided by a lead plane before dropping retardant in Pope Valley, California. August 21, 2020. REUTERS
All of the aircraft work in unison to fight the fires, many of them making multiple flights through the day, coordinated by Cal Fire OV-10 Broncos flying above for hours on end.
Aerial collaboration
Flight profiles of aircraft fighting LNU Lightning Complex fires on August 22.
1.00 pm
5.00 pm
8.00 pm
Coordinating role
Flight profiles suggest these three planes
could have been circling in higher
positions to coordinate resources
Altitude
OV-10
TACTICAL
AIRCRAFT
Tactical role
Lower altitude and could have been
acting as a “lead”, guiding tankers to targets
ST2
TANKERS
Seven tankers
made short
repeated runs
between the fire
and air base
Bae 164
DC-10
LARGE
TANKERS
MD-87
DC-10
1.00 pm
5.00 pm
8.00 pm
Coordinating role
Flight profiles suggest these three planes
could have been circling in higher
positions to coordinate resources
Altitude
OV-10
TACTICAL
AIRCRAFT
Tactical role
Lower altitude and could have been
acting as a “lead”, guiding tankers to targets
ST2
TANKERS
Seven tankers
made short
repeated runs
between the fire
and air base
Bae 164
DC-10
LARGE
TANKERS
MD-87
DC-10
1.00 pm
5.00 pm
8.00 pm
Coordinating role
These three planes could have been
flying in higher positions to
coordinate resources
Altitude
OV-10
Tactical
aircraft
Tactical role
Flight profiles suggest the two planes
could have been acting as “leads”,
guiding tankers to targets
Seven tankers
made short
repeated runs
between the fire
and air base
ST2
Tankers
Tanker no. 90
made eight
consecutive
cycles
Bae 164
Large
tankers
MD-87
DC-10
DC-10
2.00 pm
5.00 pm
8.00 pm
OV-10 - TACTICAL AIRCRAFT
Coordinating role
Possibly circling in higher altitudes
to coordinate resources
Altitude
Tactical role
Lower altitude and could have been
acting as a “lead”, guiding tankers to targets
ST2
TANKERS
Seven tankers
made short
repeated runs
between the fire
and air base
Bae 164
LARGE
TANKERS
DC-10
MD-87
DC-10
Super scoopers
Firefighting “Super Scooper” planes refill by descending to the placid waters of bays and lakes and skimming the water’s surface to load their tanks. They then release the water to douse a blaze and repeat the process until they need to refuel.
Bombardier CL-415
“Super Scooper”
Bombardier CL-415
“Super Scooper”
Bombardier CL-415
“Super Scooper”
Bombardier CL-415
“Super Scooper”
According to flight tracking data from FlightRadar24, for example, aircraft number N386AC made two flights and dozens of repeated water scoops to tackle the Woodward fire on August 23.
One Super Scooper flight on August 23
Tomales Bay
Scooping water
from the bay
Drops water at
edge of fire
Woodward fire
Two flights on August 23 from the same Super Scooper plane
Tomales Bay
Tomales Bay
Scooping water
from edge of bay
Scooping water
from the bay
Drops water at
different part
of perimeter
Drops water
at edge of fire
Woodward fire
Woodward fire
One Super Scooper flight on August 23
Tomales Bay
Scooping water
from the bay
Drops water at
edge of fire
Woodward fire
Helicopters
Cal Fire owns 12 Bell UH-1H “Super Huey” helicopters, which can each carry about 1,200 liters (320 gallons) of water in buckets hanging below the aircraft. They can be used for fast initial attacks on smaller wildfires.
UH-1H “Super Huey”
UH-1H “Super Huey”
UH-1H “Super Huey”
UH-1H “Super Huey”
The helicopters have also proven valuable when moving or evacuating firefighters and civilians. Cal Fire’s helicopter crews are trained to carry out “short-haul” rescues, which often involve a crew-member being lowered from a hovering helicopter. Once hooked to a harness or basket, the target and crew-member are carried a short distance to safety
Helicopters release water to extinguish fires in Pope Valley, California. August 21, 2020. REUTERS
On the ground, over 15,600 firefighters are battling the 19 major fires and lightning complexes burning in California as of September 1, according to Cal Fire. Since the lightning strikes that started on Saturday, August 15, there have been more than 900 new wildfires, which have now burned almost 1.5 million acres.
Sources
California Department of Forestry and Fire Protection (Cal Fire); FlightRadar24; Fire Information for Resource Management System (FIRMS); GLAD (Global Land Analysis & Discovery); Shuttle Radar Topography Mission (SRTM);
By Simon Scarr, Marco Hernandez and Manas Sharma
Editing by Daniel Grebler