Study shows correlation between rapid dispatch of air tankers and duration of wildfire

Data suggests duration of fires is shorter when air tankers are deployed early

C-130 air tanker retardant drop Canyon Fire California
A C-130 makes a retardant drop on the Canyon Fire in Napa County, California July 22, 2019. Photo by Kent Porter used with permission.

A study conducted by university researchers found that the speed of arrival of air tankers at a new fire is correlated with fires of shorter duration. Firefighters have known this for decades, but the use of data to confirm it has been lacking. It is a small step, until the eight-year Aerial Firefighting Use and Effectiveness study is released.

The research was commissioned by Global SuperTanker Services, the company that operates the 747 SuperTanker that can carry up to 19,200 gallons of fire retardant. Raw data about air tankers that were dispatched to 11,655 fires from 2014 through 2018 was acquired from the U.S. Forest Service by means of a Freedom of Information Act Request.

Keith L. Waters, Ph.D. and Stephen S. Fuller, Ph.D., of George Mason University who specialize in public policy and statistics, conducted the study. The factors they considered included the elapsed time between the first report of a wildfire and the arrival of air tankers at the fire. The duration of the fire was defined as the time between the first report and the arrival of the last air tanker over the fire.

Number Of AT Assignments Duration Of Fires air tankers

The study concluded, for example, that among 11,655 fires in which large air tankers were deployed, fires burned on average for less than one day when tankers were deployed in the first 4-6 hours of a reported fire. Fires in which tankers were deployed after 72 hours burned on average for more than 20 days.

wildfires Initial air tanker arrival

The researchers also analyzed “fires fought by the State of California”, and found that on the 6,278 fires, the California Department of Forestry and Fire Protection had air tankers over the fires within one hour of the first report 96.7 percent of the time. That compares to 37.9 percent of “fires not fought by the State of California”.

This is not a perfect study, of course, just considering fire start times and the arrival of air tankers at the scene, but the researchers were dealing with the limited information produced by the Forest Service as a result of the FOIA. It does not consider the fuels at the point of origin, the weather, availability of air tankers, time of day, ground forces assigned, helicopters working the fire, and other factors. But it does provide food for thought and a category of air tanker data that is not normally seen.

More detailed conclusions could be reached if, for example there were a dozen data collectors on the ground and in the air at numerous fires for eight years observing objectives and outcomes for individual retardant/water drops; terrain, slope, fuel type; fire spread characteristics; weather conditions and other environmental factors that may influence retardant drop effectiveness. In other words, exactly what the Forest Service has been doing in the still secret Aerial Firefighting Use and Effectiveness (AFUE) study that began in 2012.

The AFUE study is supposed to quantify the effectiveness of the various types of fixed and rotor wing aircraft when they are used on wildfires, in order to better justify the hundreds of millions of dollars spent by the Forest Service on firefighting aircraft.

In hearings before the Senate Energy and Natural Resources Committee in both 2018 and 2019 the Forest Service told the Senators the results of the study would be released “soon”. In another hearing this week before the Committee Forest Service Chief Vicki Christiansen again said it would be released “soon”. When pressed by Colorado Senator Sen. Cory Gardner, who last year made his opinion about the delay very clear, she said it would be released “this Spring”. Senator Gardner said, “Before June?”. She said, “Yes”.  A clip from that exchange is below.

Link to the entire hearing

If detailed, unfiltered, and unbiased results of the study are not released in June, the Committee could subpoena the information.

Dr. Gabbert’s prescription for keeping new fires from becoming megafires:

Rapid initial attack with overwhelming force using both ground and air resources, arriving within the first 10 to 30 minutes when possible.

Multiple aircraft to assist in Fire and Smoke Model Evaluation Experiment

NASA DC-8 study smoke plume fires
The NASA DC-8, N817NA, will be one of the aircraft used to study smoke plumes over fires.

At least 17 researchers from 12 agencies and universities will be leading various segments of a large project to develop more detailed information about wildland fires. This will be the second year of the study, titled Fire and Smoke Model Evaluation Experiment—A Plan for Integrated, Large Fire–Atmosphere Field Campaigns.

The goals include obtaining additional information about how fires burn so that new fire spread models can be developed and existing ones improved. They will also be collecting information about fire-emitted heat and emissions fluxes, near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. Both wildfires and prescribed fires will be part of the study.

The expected outcomes from the FASMEE project include:

  1. Improved scientific knowledge of the physically coupled fuels–fire–smoke–chemistry system.
  2. Exportable methodologies for measuring fuels for fire spread, fuel consumption, and fire emissions models.
  3. New insights concerning the processes that drive the spatial organization of fire energy and emissions that defines the transition between fires and plumes that impact air quality.
  4. Improvement of existing operational fire and smoke models and the development of new, more advanced models based on the collection of an unprecedented dataset (fuels, fire, meteorological, smoke plume and chemistry).
aircraft equipment study smoke plumes fires
A large assortment of ground and air based platforms will be used in the Fire and Smoke Model Evaluation Experiment.

Data collected from the ground:

  • Instruments on towers upwind, in the burn unit, and downwind.
  • LIDAR on vehicles.
  • Automatic weather stations.
  • Mobile labs.

Data collected above the ground:

  • Multiple manned fixed wing aircraft.
  • Drones, small and large.
  • Radiosonde.
  • Geostationary satellite.
  • Polar orbiting satellite.

One of the aircraft will be NASA’s *DC-8-60/70 which will be especially useful when collecting data over wildfires due to its ability to remain in the air for an extended amount of time with a range of more than 5,000 miles.

Measurements will be synchronized across time and space. This is especially critical for multi-temporal measurements of the fire and plume, for which failure will jeopardize the end-product usability. A key feature of the proposed field campaigns is that they will be designed up-front to be completely integrated with high-resolution mapping of fuels, fuel consumption, fire behavior, plume dynamics, and smoke measurements and temporally synched to provide context for related measurements (e.g., flaming fire front, heat release, and plume dynamics).

Vegetation data at prescribed fires will be collected at each site before and after the burns.  During the burns much of the work will be conducted from the ground, but multiple aircraft will also be used at the burn sites.

Prescribed fires will be studied at locations that have large projects planned:

  • Fort Stewart in Georgia
  • Department of Energy’s Savannah River Site in South Carolina
  • Fishlake National Forest in Utah, and
  • Kaibab National Forest in Arizona

More information about the Fire and Smoke Model Evaluation Experiment.

*Interesting historical note about the NASA DC-8-60/70 (N817NA) which was delivered in 1969 to Alitalia Airlines. It had an incident in 2000 (according to Wikimedia Commons) when it inadvertently flew through a diffuse volcanic ash cloud of the Mt. Hekla volcano during a flight from Edwards Air Force Base (Edwards, California) to Kiruna, Sweden. Although the ash plume was not visible to the flight crew, sensitive research experiments and instruments detected it. In-flight performance checks and post flight visual inspections revealed no damage to the airplane or engine first-stage fan blades; subsequent detailed examination of the engines revealed clogged turbine cooling air passages. The engines were removed and overhauled.

Video: Aerial Firefighting Use and Effectiveness study

Myrtle Fire air tanker p2v

Above: Air tanker 07, a P2V, on the Myrtle Fire, July 9, 2012. Photo by Bill Gabbert.

In 2015 and 2016 the Aerial Firefighting Use and Effectiveness (AFUE) study collected data on 7,000 drops of water or fire retardant on wildfires. This is partially in response to demands by Congress and the Government Accountability Office to provide actual data to justify the huge expense of using helicopters and air tankers on fires. Anecdotal information generally indicates that aircraft are effective under certain conditions to slow but not extinguish fires, however something more conclusive is needed when answering questions in front of a Congressional committee making decisions about allocating hundreds of millions of dollars.

And, we have not been able to determine, definitively, how many air tankers and helicopters are actually needed. The Forest Service likes to point to one of more than a dozen air tanker studies, the 2012 Large Airtanker Modernization Strategy, to answer this question, but it does not address the quantity of aircraft that are needed.

This video released today is an overview of the AFUE, which began in 2012.

For some reason NIFC never tells you what the acronym seen in the film, “WFSTAR”, stands for, but it is “Wildland Fire Safety Training Annual Refresher”.

Articles on Fire Aviation tagged “AFUE”.

Art Prints

Air tanker study has collected data on 7,000 drops

It will be several years before data is released about the effectiveness of aerial resources.

P2V air tankers

Above: P2V air tankers at Rapid City Air Tanker Base during the Myrtle Fire, July 21, 2012. Photo by Bill Gabbert.

The federal land management agencies spend many millions of dollars flying aircraft over fires dropping retardant or water. When Congress and the Government Accountability Office (GAO) ask how the numbers in the annual request for aerial firefighting funds were determined, they are often not satisfied with the answers, which may appear to come off the top of someone’s head. How many air tankers and helicopters do you need? How did you come up with those numbers? Are air tankers effective? How do you know?

After at least 14 studies on the use of air tankers since 1995, are the answers to these questions still scribbled on the back of an envelope?

The number of large air tankers on exclusive use contracts with the U.S. Forest Service has varied substantially in the last 15 years, from 44 in 2002 to 9 in 2013. In 2015 and 2016 there were 21 when the seasons started, plus approximately half a dozen or so on Call When Needed contracts in 2016. This year the numbers will not change much except for a few more that could be on CWN when a new round of contracts is awarded in a few months.

As we often say, aircraft do not put out fires. Under ideal conditions they can slow or temporarily stop the spread of a portion of a fire to enable ground personnel to move in and establish a fireline on the perimeter. Most wildland firefighters believe aircraft are an essential tool in their toolbox and can be very effective if used correctly. Those opinions are based on their experience on the fireground, however it is difficult to transfer that knowledge to decision-makers in Washington.

A report issued by the GAO in 2013 titled, Improvements Needed in Information, Collaboration, and Planning to Enhance Federal Fire Aviation Program Success (it is a very large file), included three recommendations:

  1. Expand efforts to collect information on aircraft performance and effectiveness to include all types of firefighting aircraft in the federal fleet;
  2. Enhance collaboration between the agencies and with stakeholders in the fire aviation community to help ensure that agency efforts to identify the number and type of firefighting aircraft they need reflect the input of all stakeholders in the fire aviation community; and
  3. Subsequent to the completion of the first two recommendations, update the agencies’ strategy documents for providing a national firefighting aircraft fleet to include analysis based on information on aircraft performance and effectiveness and to reflect input from stakeholders throughout the fire aviation community.

Under pressure from Congress and the GAO to justify the aerial firefighting program, in 2012 the U.S. Forest Service began a program to develop metrics and collect data to document and quantify the effectiveness of aircraft in assisting firefighters on the ground.

The new Aerial Firefighting Use and Effectiveness (AFUE) program gathered data from 2012 to 2014. Those first two years, USFS spokesperson Jennifer Jones told us, were preliminary to the full study:

That was done mainly as a methods development process and is not sufficient to provide statistically defensible analysis and results supporting the objectives identified by senior U.S. Forest Service leadership or GAO.

During the next two-year period, 2015 through 2016, data was collected on approximately 7,000 drops from more than 130 fires.

Mrs. Jones explained:

Since this data includes fires from many jurisdictions, fuel, weather and terrain conditions, the process of statistically characterizing the sample in terms of the population it represents requires merging data from many different sources. This work is ongoing, even for the 2015 data, but study management expects the process to be much quicker for subsequent years.

The USFS claims they have accomplished the first two items on GAO’s list regarding collaboration between the agencies. The last task is years away from completion. They plan to publish a peer-reviewed paper soon that will detail the methodology being used. Some early results of the study are expected later this year when they expect to release annual use summaries for 2015 and 2016 during 2017. Additional use summaries will come out several months following each data collection season.

After several more years when the sample size and statistical confidence increases, Mrs. Jones said, they expect to release findings related to the effectiveness and probability of success of aerial resources.

We asked Gary Barrett for his opinion about the AFUE study. Known as “Bean” to our readers, he is a former naval aviator and has contributed articles to this website. He brings a different background and point of view to the air tanker issue. Below are his comments:


“With data on 7000 drops on 130 fires over 4 years perhaps the AFUE program could have produced a report like this one [from Australia]. Or this one in the International Journal of Wildland Fire [from the US]  . Or this one [from Australia].

And if wildfire fighting in the US is being done by a combined integrated air ground team, why aren’t reports like this one available after our big fires?

Why is it that Australia seems to encourage ops analysis and its application to firefighting and here in the US we haven’t caught up with the concept. Until US ops analysis gets going, there will be no definitive answers on the utility of US air tankers and how they are utilized.

Even New South Wales in Australia has an opinion on the utility of heavy air tankers and has initiated a study on large air tankers operating in Australia.”

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Aviation-Related Wildland Firefighter Fatalities — United States, 2000–2013

Aviation Fatality Map wildland fireThe Centers for Disease Control and Prevention has published the results of a study that collected information about aviation-related fatalities of wildland firefighters between 2000 and 2013. You can see the entire paper HERE (see page 793), but most of it is below.


Aviation-Related Wildland Firefighter Fatalities — United States, 2000–2013
July 31, 2015 / 64(29);793-796

Corey R. Butler, MS1, Mary B. O’Connor, MS2, Jennifer M. Lincoln, PhD2 (Author affiliations at end of text)

Airplanes and helicopters are integral to the management and suppression of wildfires, often operating in high-risk, low-altitude environments. To update data on aviation-related wildland firefighting fatalities, identify risk factors, and make recommendations for improved safety, CDC’s National Institute for Occupational Safety and Health (NIOSH) analyzed reports from multiple data sources for the period 2000–2013. Among 298 wildland firefighter fatalities identified during 2000–2013, 78 (26.2%) were aviation-related occupational fatalities that occurred during 41 separate events involving 42 aircraft. Aircraft crashes accounted for 38 events. Pilots, copilots, and flight engineers represented 53 (68%) of the aviation-related fatalities. The leading causes of fatal aircraft crashes were engine, structure, or component failure (24%); pilot loss of control (24%); failure to maintain clearance from terrain, water, or objects (20%); and hazardous weather (15%). To reduce fatalities from aviation-related wildland firefighting activities, stringent safety guidelines need to be followed during all phases of firefighting, including training exercises. Crew resource management techniques, which use all available resources, information, equipment, and personnel to achieve safe and efficient flight operations, can be applied to firefighting operations.

Airplanes and helicopters play a major role in the control of wildland (forest, brush, and grass) fires. These aircraft are used to deliver equipment and supplies, deploy and transport firefighters, conduct reconnaissance, scout and direct operations, and deliver fire retardant or water. During the past decade, the United States has experienced an increase in the size, frequency, and severity of wildfires, likely attributable to buildup of flammable vegetation, decline in snowpack, and human development in the wildland urban interface (1,2). If these conditions continue, more fire response workers will be needed, and the demand on aviation to support these efforts will increase.

To identify risk factors for aviation-related wildland firefighter activities, NIOSH reviewed and extracted case reports from the Fire Administration Firefighter Fatality surveillance system, the National Fire Protection Association Fire Incident Data Organization database, the National Wildland Coordinating Group’s Safety Gram, and the National Transportation Safety Board aviation database. A wildland firefighter fatality was defined as any death that occurred in a paid or unpaid wildland firefighter, contractor, aviation crew member or support staff, inmate, or member of the military while performing official wildland fire duties, including operations (fire or nonfire incident), responding to or returning from a wildland fire incident, or other officially assigned duties.* Other emergency response workers who were fatally injured at wildfires were excluded from this analysis. The number of flight hours for the U.S. Forest Service was used as a denominator to indicate the use of aviation resources because flight hours from other agencies or workforce numbers were not available.

During 2000–2013, a total of 298 wildland firefighter fatalities were identified, averaging 21 fatalities per year. Among these, 78 (26.2%) were caused by activities associated with aviation. The number of aviation- related fatalities decreased during 2007–2013, compared with 2000–2006 (Table 1). Of the persons who died in aviation-related activities, 76 (97%) were male, and 53 (68%) were flight crew members (e.g., pilots, copilots, and flight engineers). The average age of flight crew victims was 49 years (range = 20–66 years) and of nonflight crew victims was 33 years (range = 19–54 years). The most common occupation of nonflight crew members was firefighter. Most victims were employed by aerial contractors (42), followed by the federal government (15), state government agencies (10), ground contractors (seven), and the military (four). Twenty-five (32%) of the aviation-related fatalities occurred in California, eight occurred in Nevada, and seven in Idaho (Figure).

Aviation Fatalities wildland fire

Continue reading “Aviation-Related Wildland Firefighter Fatalities — United States, 2000–2013”

Center of Excellence for Advanced Technology Aerial Firefighting to be open soon

Melissa Lineberger
Melissa Lineberger Interim Director of the Center of Excellence for Advanced Technology Aerial Firefighting, and Paul Cooke Division of Fire Prevention and Control Director. Photo by Garfield County Rifle Airport.

(UPDATE at 9 p.m. MDT, May 15, 2015: After “Phil” left a comment below saying “Director Cooke selected Ms.[Melissa] Lineberger as the Center’s Director on Wednesday”, we checked with the Colorado Division of Fire Prevention and Control to confirm, and it is true. She is a licensed attorney who joined the state Division of Fire Prevention and Control in 2013 as a policy analyst before taking her interim position last August.)

(Originally published at 2:11 p.m. MDT, May 15, 2015:)

This week in Rifle, Colorado there was a ribbon cutting for the ceremonial opening of Colorado’s Center of Excellence for Advanced Technology Aerial Firefighting. Later this summer the Center will be working out of a facility at the Garfield County Rifle Airport.

Radio station KRCC conducted an interview with the interim Director, Melissa Lineberger. Below is an excerpt:

AHM:  Exactly what will your duties be?

LINEBERGER:  As the director, I’ll be responsible for the day-to-day operations of the center, ensuring that we are meeting our goals as far as completing projects on time, communicating with the legislature to ensure that they understand what we’re doing, and then also being involved as a spokesperson to the Colorado firefighting community, make sure that they understand when we have a new tactic, technique or procedure, understand how that can be implemented and how that can help them, and then provide whatever training is necessary.  [Are] demonstrations the best way to go?  Or is it sitting down in a classroom and having them see the process that we went through to get to a solution?  I’ll be in charge of overseeing all that and making sure the staff is as excited as I am for this opportunity and is moving forward in the right direction.

AHM:  What projects are you looking at right now?

LINEBERGER:  Some of the initial projects that I’ve already started doing research on [are] night operations. Right now we’re not doing bucket drops from the air at night on fires because 30-40 years ago there were some high profile helicopter crashes when they were trying to fly at night.  But night-vision goggle technology has come a long way.  People have been scared to re-implement [night-time aerial bucket drops] because of the safety issue.  So what we want to do is look into the safety, talk to the folks who are doing night flying currently with the National Guard and with some other organizations, and try to figure our how we can get night operations on our fires here in Colorado.  There’s a lot of benefits to fighting fire at night, the smoke lays down, and there’s just opportunities for us to attack those fires 24 hours a day from the air.

According to the Post Independent, ”

… the state Division of Fire Prevention and Control expect to complete a job description for the director soon, followed by a “rigorous” selection process that could take two or three months. After that, they can began hiring the remaining eight full-time staff members, who will occupy an existing building that is being vacated by Garfield County.

Air tankers, retardant, and studies

The following  is written by Gary Barrett, also known as “Bean”, a former naval aviator who has contributed an article or two previously and regularly leaves comments on the website. He brings a different background and point of view to the air tanker issue.


This Australian technical report on tanker effectiveness is the one that the USFS has been unable to accomplish since 1968.

An illustration from the report on air initial attack alone:

Fire Danger-1st Attack Success

Combined attack vs integrated attack:

Decision Tree First Attack Success with air tankers

If the USFS had a similar document on the effectiveness of initial attack in 5 fuel hazard types by tanker/ crew arrival time [page 3 and 4 of referenced technical paper] , they would have been able to defend their requirements for tankers and ground equipment to congress, determine basing requirements, and contract availability requirements by type.

From previous experience in targeting for Navy tactical strikes, it is critical that the effectiveness of what you drop is known scientifically and described mathematically. The military has determined a munition effectiveness probability number for everything it has. It tells you how many aircraft of what type with what munitions you send on a strike against a particular type of target. The Naval Strike Warfare Center in Fallon NV stood up in the mid 1980’s to teach the tactical carrier Navy how to fight smarter, not harder … Google “Torpedo 8” and look at the battle of Midway to see a classic example of where fighting harder got us. We had plenty of other later examples of the same fight harder problem that indicated we were not a “learning organization”. We tended to use technology to enable us to do more of what we always used to do [fight harder].

It seems to me that the issue with using aircraft to fight fires in the US is in pretty much in the same place that Navy TACAIR was before the Strike Warfare Center stood up in the mid 1980’s. The usual answer from today’s firefighting community seems to be “fight harder” and more is better. You can’t fight smarter until you get smarter. If that means setting up canned experiments in controlled burns and collecting data, then do it. More contract studies with the dearth of information available today are useless.

The firefighting community should develop formal definitions of probability of success for each type of air tanker based on lets say 5 fuel types or hazard conditions, types of retardant, terrain slope, release parameters, and coverage levels or they will never get where they need to go when it comes time to decide how many tankers of what type carrying what kind of retardant, based where under what kind of contract is required to achieve a certain probability of success. When the time comes, you use what you have but if you have a “smarter program”, there is a better chance of having the right stuff where you need it when you need it.

Rhetorical question: What is the probability of success for a line of X level coverage of retardant [pick the type] on fuel hazard class Y in terrain of slope Z? Can’t answer? Your only solution then is to “fight harder and more is better”.

Congress and GAO have already demonstrated that they aren’t interested in the “trust me I’m a career firefighter with a zillion hours of experience and we need more” argument. One could say that the industry with the best track record for getting money from congress is the military-industrial complex and they never use the “trust me” argument.

Getting smarter enables the profession to escape from the apprentice … journeyman … master training cycle that requires a lifetime of experience, critically depends on the questionably cohesive informal knowledge held by the various “masters” and significantly limits the numbers that can be effectively trained in the profession. For all I know, if more was understood about retardant effectiveness under various conditions, different more effective tactics could be developed to deal with wildfires. Better ways of getting the job done could be developed. Firefighters could fight smarter not harder.

Where’s the published US tactics manual for aerial firefighting? It could start with the two graphs above and grow from there. All ex military aviators lived by their tactics manual for their particular aircraft. It explained what you did with the aircraft after you learned how to fly it.

Gary Barrett (Bean)


Demonstration of fire retardant effectiveness

This video, featuring Shirley Zylstra, the Wildland Fire Chemicals Program Leader for the U.S. Forest Service, demonstrates the effectiveness of long term fire retardant dropped by air tankers, and occasionally by helicopters. In the video that was uploaded to YouTube yesterday, Ms. Zylstra explains how the chemical works even after the water evaporates by interfering with the combustion process.

The video is extremely low resolution, 240p, and looks like it was recorded with a flip phone, but it gets the message across.