Results released for study of water enhancers used by firefighting aircraft

Five products were evaluated during a three-year period

CoE water enhancer study fire

Results have been released for a three-year study on the use and effectiveness of water enhancing products for Single Engine Air Tankers (SEATs). It was conducted by Colorado’s Center of Excellence (CoE) for Advanced Technology Aerial Firefighting, and the Bureau of Land Management from 2017 through 2019. It is titled, “Aerial Firefighting Field Operational Evaluation of Water Enhancers; Results and Recommendations.”

In addition to long term fire retardant (LTR) which is usually used in large and very large air tankers, other water enhancing products are often used by SEATs and sometimes helicopters, and occasionally by large air tankers. For example the air tankers from North America that worked in Chile in recent years used products other than LTR. The enhancers are also used in Australia in addition to LTR. SEATs often use retardant but some bases have switched to other products.

Data was collected for the study through 95 evaluations of the performance of the water enhancers by aerial supervision personnel, pilots, ground firefighters, a mixer-loader, and by two dedicated field observers hired for that purpose during the final year of the project.

The CoE evaluated the following water enhancers:

  • GelTech Solutions FireIce 561® (uncolored)
  • FireIce HVO-F® (orange colorant)
  • FireIce HVB-Fx®
  • G5 BioSolutions BlazeTamer 380®
  • Thermo Technologies Thermo-Gel 200®

(In the interest of full disclosure BlazeTamer is a supporter of Fire Aviation.)

The full 63-page report can be downloaded. Here are some of the recommendations:

Increase the Use of Water Enhancers (Especially During Initial Attack)

Aircraft are used in a variety of wildfire management roles in many parts of the world. They can be used to deliver suppressants to sections of the fire edge that are difficult to access on the ground and can reduce the intensity and spread rates to allow ground crews to work along the fire edge. This is critical during the initial attack of wildfires in remote locations.

When used properly, specifically in direct attack on the fire with ground resources present, the CoE’s data showed that there is a favorable reduction in flame heights with the use of water enhancers as opposed to LTR, especially in light fuels. Observers shared a number of comments that suggest that they are quite effective at reducing fire behavior.

  • Water enhancers are much more effective when used in direct attack than water or foam and much less expensive than retardant.
  • The choice of tactics may also depend on the availability of suitable aircraft, payload, and airbase facilities for each option.
  • Water and foam all dry at a faster rate than do water enhancers; however, ground follow-up is critical to the success of a water enhancer line “holding.” This is even more important on hot and windy days when spread rates and the probability of ignition are both high, as holding times under these conditions will be 30 minutes or less.
  • Holding time was difficult to quantify because many of the drops were not observed at all or did not last long enough to capture data.
  • The CoE’s study showed that holding times for the products that were evaluated range from 20 minutes to 2 hours. Because the water enhancers are only effective as long as they retain water, fire managers must realize that the use of these products should be limited to direct attack applications.

Consider Use of Water Enhancers in Helicopters

Use of water enhancers in helicopters should also be considered on large fires to directly support crews in controlling hot spots and reducing the amount of time required to control critical sections of fireline.

Some additional benefits of water enhancer use in helicopters may include:

  • Fireline production per drop when using water enhancers is increased significantly due to the creation of a dense, narrow drop pattern versus the pattern created when dropping untreated water.
  • Retardant is expensive and inefficient when used for direct attack.  Retardant increases the weight of water from 8.3 lb per gallon to about 9.1 lb per gallon.
  • Only 85% of retardant (i.e., the water content) is effective when used for direct attack; 15% is the chemicals and coloring agent used for indirect attack.
  • Retardant is more expensive. For example, BlazeTamer 380 costs $0.83 per gallon as compared to $2.50 per gallon for Phos Chek 259-F LTR.
  • Ease of set-up and breakdown of water enhancer mixing systems as compared to mobile retardant bases allows for fast movement around a fire rather than having to stay in one location. No heavy equipment is needed.

Use Water Enhancers with Prompt Ground Resource Follow-Up

When enhancers are used properly for direct attack and the number of aircraft is sufficient, they may be capable of fully extinguishing the fire with little to no ground support. The CoE recommends water enhancer use for situations where follow-up from the ground can be provided promptly (typically within 1 hour).

For an extended attack incident, particularly when the ground support is several hours away and the need is to hold or slow the spread until they can catch up, retardant is likely the best tool. There were numerous observations made during this study in which the enhancers were very effective when supported by ground resources. Ground crews play an essential role during fire suppression, with water enhancer technology offering a method to increase their suppression capacity. Aerial suppression provides a temporary holding role, rather than extinguishing fires. Follow-up by ground crews before the water enhancers dry out or fire burns through the drop zone is essential.

In 2018, the CoE received observations from several initial attack fires with high rates of spread and intensity where ground resources were delayed in supporting the drops in a timely manner, resulting in drops being burned around or spotted over.

There were other recommendations about training, using an aircraft with an electro-optical/infrared sensor to evaluate the effectiveness of the drop, and processes to ensure quality control of the water enhancer mixture.

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.

Senators question why results from air tanker study have not been released

U.S. Forest Service Chief Vicki Christiansen testified before the Senate Energy and Natural Resources Committee

CL-415. Photo by LA County Fire Department.
CL-415, October, 2013. Photo by LA County Fire Department.

In addition to grilling the Chief of the Forest Service about hostile workplaces, several other issues were covered in a hearing Tuesday before the Senate Energy and Natural Resources Committee.

A video recording of the hearing is available at the Committee’s website. It begins at 19:48.

Senator Lisa Murkowski, Chairperson of the committee, said (at 1:39:30 in the video) that a year ago the committee was told by the Forest Service that results from the Aerial Firefighting Use and Effectiveness (AFUE) study would be released “soon”. Launched in 2012, the 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 FY 2017 for example, the most recent year with exact numbers available, the agency spent over half a billion dollars on fire aviation; $507,000,000. If ever completed and the results implemented, the study could make it possible to answer the question: “What are the best mixes of aircraft to do any fire suppression job?” Data collected from this study and other sources would be used to inform decisions about the composition of the interagency wildland firefighting aircraft fleet — to use the best, most efficient tools for the job.

However, to date no detailed reports have been released from the AFUE.

The Senator asked about the results of the study, now entering its eighth year. The data is being collected by four “observation modules,” each comprised of three qualified firefighters and a dedicated aircraft, to collect ground and aerial data at wildfires throughout the nation during fire season. In addition to the 12 firefighters, 3 analysts/managers evaluate the data. Christine Schuldheisz, a spokesperson for the USFS, has said the annual cost of the project is approximately $1,300,000.

Chief Christiansen, referring to the lack of any detailed results being released, said, “I absolutely share your concern and your question….. I am low on patience as well, Senator. This is a complex and labor intensive endeavor.”

Senator Murkowski: “But should it really require seven years to get a report like this?”

Chief Christiansen: “To have enough, when you have to take these assessment teams and have to be on the fire scene and to get enough data to get what the trend line is, it does take some time.”

The Chief then referred to a very small amount of preliminary data that was released in a two-page document in March which in a vague manner referred to the probability of success of direct vs. indirect attack by aircraft. This was was reported by Fire Aviation April 8, 2019.

Senator Murkowski asked the Chief to have more details from the AFUE study when the Committee holds their annual fire outlook hearing in about a month.

Since after seven years the Forest Service has not released any significant data about the study, a person has to wonder what they have found that is so embarrassing, controversial, or perhaps critical of specific models of aircraft, retardant products, or vendors?

Some people think the Forest Service will never release the full results of the AFUE study.

The Committee might have to subpoena the data.

Later in the hearing (at 1:43:30) Colorado Senator Sen. Cory Gardner referred to the study, saying in his rapid-fire speaking style: “There is a technical term I want to use to describe the length of time it is taking to get that study done, and it is bunk! I’m sorry, it’s just a bunch of bunk that it has taken seven years to get this done. We fought a world war in four years, we built the Pentagon in 16 months, we can’t do a study in 2 years, 1 year, 3 years, 4 years, maybe 5 years? It has taken seven years to do this? In the meantime we have western states that have had significant and catastrophic fires. I understand it’s important to get the information right. But doggonnit, someone needs to get a fire lit underneath them to get something done on this study.”

Washington Senator Maria Cantwell mentioned very briefly in the hearing (at 59:00 in the video) the availability of CL-415 water scooping air tankers but the issue was not discussed. The Forest Service, even though funds are available and a vendor offered the usually very expensive aircraft at a greatly reduced rate this year in a meeting with Chief Christiansen and Fire Director Shawna Legarza (according to our sources), the agency does not plan to have any scoopers on exclusive use contracts for the second year in a row. Historically the FS does not hold scoopers in high esteem even though they are used extensively in Canada and Europe. The 2012 Rand Study, which the agency attempted to keep secret (and did so successfully for two years), recommended a heavy emphasis on water-scooping air tankers and fewer conventional air tankers which would have been a monumental shift in the paradigm.

On another subject, New Mexico Senator Martin Heinrich expressed concern that the Administration intends for both the Collaborative Forest Landscape Restoration Program (part of the Forest Service) and the Land and Water Conservation Fund (under the Department of the Interior) to be unfunded beginning in October. Again, the Chief mentioned that the White House directed the Forest Service to cut its overall budget by five percent.

Referring to the fact that the “fire fix” has reduced the necessity for the Forest Service to borrow funds from unrelated accounts to pay for fire suppression, Senator Heinrich said, “We’re giving you the tools, you’re not using the tools we are giving you.”

At 56:30 in the video Senator Cantwell asked Forest Service Chief Vicki Christiansen about the $545 million that was appropriated for fuel management in the recent omnibus legislation but was not mentioned in the administration’s proposed budget for FY 2020 which begins October 1. The Senator asked for assurances that the funds would still be available and would be used for that purpose. The Chief would not commit to the funds still being available, saying, “We will use whatever resources are given to the agency”.

The Chief reminded the Senator that the White House directed the Forest Service to cut its overall budget by five percent.

After seven years of the air tanker effectiveness study, what have we learned?

In FY 2017 over half a billion dollars was spent by the U.S. Forest Service on firefighting aircraft

A K-MAX helicopter drops water on the Comet Fire north of Salmon, Idaho July 28, 2016. Photo by Bill Gabbert.

This year the Aerial Firefighting Use and Effectiveness (AFUE) study that started in 2012 will begin its eighth season.

The Government Accountability Office in 2013, a 2009 audit by the USDA’s Office of Inspector General, and Senators and Congressmen have asked questions about justifying the taxpayer’s funds that are annually allocated for firefighting aircraft by the federal government. When asked if aircraft were worth the cost and if they were effective the answers from the land management agencies have been, “Yes”. How do you know? “We just do”. (I’m paraphrasing here).

According to the Administration’s FY 2020 budget summary, over half a billion dollars was spent on fire aviation in FY 2017; $507,000,000.

The U.S. Forest Service started the AFUE in an effort to answer the question: “What are the best mixes of aircraft to do any fire suppression job?” Data collected from this study and other sources would be used to inform decisions about the composition of the interagency wildland firefighting aircraft fleet.

After seven years of the study, which costs about $1.3 million annually, very little information has been released about the status of the effort or any detailed findings that have been developed. It is almost as if the Forest Service is less than enthusiastic about what they have discovered so far. In fact, a reliable source told us that one or more high-ranking folks in the agency want it to “go away” and that detailed findings would never be released. The USFS refused to release the $840,092 RAND air tanker study completed in 2012 even after we filed a Freedom of Information Act Request. Finally RAND released it two years after it was completed, but as far as we know the USFS never did. That study recommended a heavy emphasis on water-scooping air tankers and fewer conventional air tankers, which would have been a monumental shift in the paradigm.

When we asked Christine Schuldheisz, a Forest Service spokesperson, when a report from the AFUE study would be released, she said, “The USDA Forest Service has not released a report and currently the agency does not have a timeframe to release a report. The Forest Service is collecting data to provide adequate information for a report that will be released in the future.”

We asked if the Forest Service wanted the study to “go away”, and she said, “USDA Forest Service has no plans to discontinue the AFUE program at this time.”

In stories like this, we often include the disclaimer that air tankers do not put out fires. Under ideal conditions aircraft can slow a fire enough to allow ground based firefighters an opportunity to contain sections of the fire’s edge by constructing a fireline. Strong winds or dense smoke can make it impossible for aircraft to operate safely or effectively.

The data is being collected by four “observation modules,” each comprised of three qualified firefighters, as well as a dedicated aircraft, to collect ground and aerial data at wildfires throughout the nation during fire season. In addition to the 12 firefighters, 3 analysts/managers evaluate the data. Ms. Schuldheisz said the annual cost of the project is approximately $1,300,000.

After the first three years the AFUE, the Forest Service found that the data collected from 2012 through 2014 could not be used to provide statistically defensible analysis and results. After making the necessary adjustments to their procedures, they made a commitment to begin releasing detailed annual aircraft use summaries several months after each collection season. The annual reports were scheduled to begin in the early months of 2017 for 2015-2016. By now three reports should have been issued.

Ms. Schuldheisz told us that annual reports have not been released but she sent us a copy of a two-page “Fact Sheet” about the program that she said was sent to Congress in March, 2019. (Another one-page “Fact Sheet” was released in 2017.) The recent document includes information about data collection and the preliminary information shown below about probability of success.

AFUE air tanker study
* Direct: Any treatment applied directly to burning fuel such as wetting, smothering, or chemically quenching the fire. This includes drops adjacent to the active fire or with limited unburned fuels between the drop and fire edge. Whenever you hear the requestor suggest that the intent of the drops was half in and half out, select direct for tactic.
* Indirect: A method of suppression in which the control line is located some distance away from the fire’s active edge. Generally done in the case of a fast-spreading or high-intensity fire and to utilize natural or constructed firebreaks or fuel breaks and favorable breaks in the topography. The intervening fuel is usually backfired; but occasionally the main fire is allowed to burn to the line, depending on conditions. Source: US Forest Service.

The two-page Fact Sheet has some preliminary information from 2015 to 2017 with enough data to report with high confidence, Ms. Schuldheisz said.

  • Rotor-wing aircraft data indicates an 87% probability of success in direct attack drops, and 62% in indirect attack drops.
  • Fixed-wing aircraft data indicates a 74% probability of success in direct attack drops, and 56% in indirect attack drops.
  • Rotor-wing and fixed-wing have different mission profiles with a varying degrees of complexity. Both aircraft types fly direct attack missions the majority of the time.

When we asked how the researchers defined “success”, Ms. Schuldheisz replied:

Data is collected in multiple, nested scales which account for requestor objectives and then compare those to outcomes achieved at each scale and across various resource configurations.  The AFUE developed hierarchical data groupings of: Resource Actions, capturing information about individual drops; Tasks, to aggregate multiple, coordinated individual resource actions, over the course of one shift or less, in support of the task work assignment; and Campaigns, to group multiple aerial and ground tasks, working in concert, for a measurable amount of time, in a defined geographic area, supporting incident objectives. By documenting outcomes independently of objectives, effectiveness can be accurately determined.  To translate effectiveness into the observed probability of success, we divide the effective outcomes by the sum of effective and ineffective. Observed probability of success shows how often drops tested by fire meet or exceed their intended objective.

The Forest Service AFUE webpage includes these questions they hope to answer:

  • The best mixes of aircraft to do any fire suppression job.
  • Composition of the interagency wildland firefighting aircraft fleet.
  • Track the performance of specific aircraft types.
  • Assess the influence of the operational missions that drops supported and environmental factors that influenced outcomes.

We assume, with few details having been released by the Forest Service, that the study will collect data about four to five types of fixed wing aircraft (single engine, scooper, large, and very large) and at least three types of helicopters, Types 1, 2 and 3. Breaking it down by aircraft model and vendor would also be helpful. The type of fluid that is dropped should be recorded: water, long term fire retardant, or water with some other enhancement product.

If the study can determine the effectiveness of each of these seven types of firefighting aircraft, it should not only lead to answers about which ones are most effective, but also under what conditions of wind, terrain, fire behavior and fuel types they should be used.

Hopefully it will lead to answers to the questions from the GAO, Inspector General, and Congressmen about justifying the half billion dollars of taxpayer funds spent each year.

If the study can actually quantify the on-the-ground effective production rates of each type of firefighting aircraft, an analyst should then be able to develop a recommendation for how many of each type are needed nationwide and where they should be based.

And beyond that, algorithms or artificial intelligence could eventually, based on scientific data, make on-the-fly recommendations for which aircraft should be dispatched after a report of a new fire, based on availability of aircraft, aircraft production rates, location of the fire, fuel type, fuel moisture, terrain, scooping sites, location of reload bases, congestion at reload bases, weather, and predicted fire behavior.

At 10 a.m. EDT on April 9 the Senate Energy and Natural Resources Committee will hold a hearing “to examine the President’s budget request for the USDA Forest Service for Fiscal Year 2020.” It will be interesting to see if Chief Vicki Christiansen is asked questions about the AFUE. These hearings are usually live-streamed.

Gary (Bean) Barrett, a frequent contributor to the discussions on Fire Aviation, spent a career in U.S. Naval  Aviation as a fighter pilot and served on the Navy Staff as a program sponsor responsible for planning, programming, and budgeting. Here are some of his thoughts about the information that has been released so far about the AFUE:

This Australian air tanker effectiveness study defined results in terms of probability of success in meeting a common first [initial] attack objective of containment within 8 hours of detection. They didn’t try to differentiate between success and effectiveness in their report. They produced an excellent operationally useful study based on probability of suppression that begs for a follow-on study to compare different tanker types.

“Maybe the AFUE effort is suffering from excessive complexity by trying to address all the air tanker success, effectiveness, efficiency, and use questions on the first report. I would think it might be useful to get out an initial AFUE report with less complexity, get feedback, and then refine and expand it as more data becomes available each year. Here’s an example of an excellent report using partial data that produced an operationally useful document.

“AFUE might consider coming out with a partial report by focusing on IA objectives with basic variables. Simplify the process. If they are trying to get everything done in the first report, that just might be a bridge too far and the reason we haven’t seen any reports yet.”

Study recommends keeping Medford Air Tanker Base open

Medford is 55 miles away from another base at Klamath Falls

Neptune tanker 01 41
Neptune tankers 01 and 41 at Medford Air Tanker Base June 9, 2016. Photo by Kristin Biechler.

A recent study commissioned by the U.S. Forest Service recommends keeping the air tanker base at Medford, Oregon open if other agencies can begin paying a portion of the $245,000 annual operating costs. Apparently closing the base was on the table, in part because it is only 55 miles away from another base at Klamath Falls, Oregon.

Local politicians in Oregon have been working to keep Medford open after word spread in March that the study was underway.

Below is an excerpt from an article in the Mail Tribune:

“Closure of either base at this time would be counterproductive to ensuring rapid response times to initial attack of fires since both bases are fully functional and in good condition,” Northstar Technology Corp. concluded in the study.

The study found that the savings from closing one base would be gobbled up by the $281,000 increased costs of flying retardant further distances from the one remaining base.

With two open, one base can keep operating if the other is socked in with smoke, the study said.

Forest Service officials said the trend of larger fires appears to be migrating northward, making reliance on the air tanker bases more vital for Western Oregon and Northern California.

air tanker 910 Medford
Air Tanker 910 departs from Medford, July 28, 2017, en route to the Lake Fire in northeast California. Photo by Tim Crippin.

Thanks and a tip of the hat go out to Kelly.
Typos or errors, report them HERE.

Hard data on air tanker effectiveness still not available

Results have not been released from the Aerial Firefighting Use and Effectiveness study that began in 2012

BAe-146 drops on Devore Fire
BAe-146 drops on the Devore Fire, November 5, 2012. Photo by Rick McClure.

The federal government spends around $100 million each year on large air tankers. A reasonable person would hope that the results of a very careful analysis determine the performance specifications and effectiveness of aircraft that are needed to assist firefighters on the ground to the greatest extent possible while still being a careful steward of taxpayers’ money. If the effectiveness of air tankers can’t be quantified, how to spend that $100 million is left up to the gut feelings of decision makers.

In stories like this, we often include the disclaimer that air tankers do not put out fires. Under ideal conditions aircraft can slow a fire enough to allow ground based firefighters an opportunity to contain sections of the fire’s edge by constructing a fireline.

Government officials often mention the 2012 Large Airtanker Modernization Strategy as a blueprint. However, that document does not make any independent conclusion about the number or types of air tankers. If you wade through the footnotes it actually refers to a 2009 study that recommended increasing the number of large air tankers on exclusive use contracts from 19 in 2008 to 32 in 2018. In addition there would be three water scooping air tankers by 2018, bringing the total up to 35.

report released by the Government Accountability Office in 2013 about air tankers pointed out some of the same issues that were in a 2009 audit by the USDA’s Office of Inspector General. Both reports emphasized that the U.S. Forest Service and the Department of Interior need to collect data about the effectiveness of air tankers and put together a coherent plan on the management of the fleet, and a plan for the acquisition and justification of additional aircraft.

Due to these reports and repeated questions over the years by Senators and Congressmen, in 2012 the Forest Service began an effort to answer the question: “What are the best mixes of aircraft to do any fire suppression job?” Data collected from this study and other sources would be used to inform decisions about the composition of the interagency wildland firefighting aircraft fleet. The study was named the Aerial Firefighting Use and Effectiveness (AFUE) Study.

On a Forest Service web page the agency describes when data would be released:

AFUE study
Screenshot from

Now that it is June, 2018 we should have seen the data from at least 2015, 2016, and 2017. But, it is not available.

When we asked Vicki Christiansen, the Interim Chief of the Forest Service, when the study’s results would be released, she responded by email, “AFUE personnel have been making excellent progress and continue to engage agency leadership on performance metrics, data collection, analysis and tech transfer processes to support a transition to an operational performance reporting system. Currently the program is funded until 2022.”

After we asked for more information, she wrote, “Summaries of the Aerial Firefighting Use and Effectiveness (AFUE) Study where planned for release in 2017. However, the summaries are not currently available. Unforeseen delays with staffing changes, retrieving aviation use data, and completing final reviews has delayed their overall schedule. The AFUE work group is continuing their work to complete the summaries and they will be provided as soon as they become available.”

Some would think that developing actual data to determine how to spend $100 million, year after year, should be a very high priority and would lead to finding solutions to staffing changes, retrieving aircraft use data, and completing reviews.

To our knowledge the Forest Service never did release the findings of an air tanker study conducted by the Rand Corporation in 2012 even after we filed a formal Freedom of Information Act Request. The report was finally released by Rand two years after it was completed. When awarding the $840,092 contract the Forest Service told the company to not consider Very Large Air Tankers at all in making their recommendations for how the air tanker fleet should be configured. The study found that “the most cost-effective fleet of initial attack aircraft is dominated by scoopers, but airtankers play a niche role, particularly in fires that are not close to appropriate water sources.” In one variant, Rand said, “the optimal fleet is composed of eight 3,000-gallon airtankers and 48 1,600-gallon scoopers”.

We heard from sources that the Forest Service was not pleased with Rand’s recommendations. It remains to be seen if the agency will release all of the data and conclusions from the AFUE study that is now in its seventh year.

Gary (Bean) Barrett, a frequent contributor to the discussions on Fire Aviation, spent a career in U.S. Naval  Aviation as a fighter pilot and served on the Navy Staff as a program sponsor, responsible for planning, programming, and budgeting. Here are some of his thoughts about determining the composition of a fleet of aircraft:

“It’s been my observation that if you don’t know how to derive your asset inventory objectives then you can’t explain or defend why you have chosen today’s particular inventory objectives.

“If you can’t determine the effectiveness of each type of asset, you cannot explain why today’s particular inventory mix was chosen or why certain trade-offs were made due to budget cuts.

“If you don’t know whether your primary mission requirement is Initial Attack or Extended Attack you cannot determine the mix of Exclusive Use contracts that can support IA, and Call When Needed contracts that take longer to get an asset on scene and would best support EA.

“Not much will change until:

1. The mission is clearly defined.
2. The effectiveness of each type of asset utilized for mission execution is known.

“At that point, budget impacts can be defined and dealt with objectively, contracts can be written that will provide the most mission effectiveness for the least cost, and the USFS will have definitive answers to questions about asset inventory, asset mix, and EU vs CWN contract mix.

“I still believe AFUE is the key to getting all of this off of bureaucratic dead center. Until you understand tanker effectiveness you cannot determine and justify inventory objectives.”

Does anyone know how many large air tankers we need?

Two studies, completed 10 and 21 years ago, said there is a need for 35 or 41 air tankers.

Air Tanker 910 DC-10

In the interview with Shawna Legarza published on Wildfire Today this morning, the National Fire Director for the U.S. Forest Service said in response to a question about how many large air tankers are required:

I would say we need anywhere from 18 to 28, you know that’s what it says in the [2012 Large Airtanker] Modernization Strategy. I think that’s a good range.

We re-read that Strategy, and could not find any independent conclusion reached by the authors about the number of air tankers. But, on page 3 there was this:

Continued work is ongoing to determine the optimum number of aircraft to meet the wildfire response need, but studies have shown that it is likely that between 18 and 28³ aircraft are needed.

The referred to footnote #3 is this:

³The requirements for large airtankers have been derived from the “National Interagency Aviation Council Phase III Report, December 7, 2007”, and the “Interagency National Study of Large Airtankers to Support Initial Attack and Large Fire Suppression, Phase 2, November 1996”.

The first of the two studies recommended increasing the number of large air tankers on exclusive use contracts from 19 in 2008 to 32 in 2018. Plus, there would be three water scoopers by 2018, bringing the total up to 35. The table below is from the study.

fire Aviation Strategy
Screen grab from the 2007-2009 NIAC Interagency Aviation Strategy document. Phase III, page 21.

The second document, the 21-year old study from 1996, recommended 20 P3-A aircraft, 10 C-130B aircraft, and 11 C-130E aircraft, for a total of 41 large air tankers.

The “18 to 28” air tankers mentioned in passing in the “2012 Large Airtanker Modernization Strategy” is not reflected in the referrals indicated in the footnote.

Much has changed in the world of aerial firefighting in the 10 to 21 years since those two studies were written. (They are two of the 16 air tanker studies and reports listed on the Wildfire Today Documents page.)

But what has not changed is that the numbers in these studies, written by smart, well-meaning people, are basically back of envelope stuff. There has not been in the United States a thorough, well designed analysis of the effectiveness of aerial attack, exactly how much retardant is needed in a certain time frame, where aircraft need to be based, and how many and what type of aircraft are required.

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. This became the Aerial Firefighting Use and Effectiveness (AFUE) program. It will be several more years before they expect to release findings related to the effectiveness and probability of success of aerial resources.

We asked “Bean” Barrett, a frequent contributor on Fire Aviation, for his view on how many air tankers are needed. He started by saying the general theme of the letter written in 2012 by Ken Pimlott, the Director of CAL FIRE, to the Chief of the Forest Service, is still applicable today. Director Pimlott said in part that the then-recent USFS Large Air Tanker Modernization Strategy was insufficient to meet the needs of the combined federal, state and local wildland firefighting missions.

Bean’s further input is below.


“18-28 Large Air Tankers as the Federal inventory objective? Could we be a little more precise? What if the federal requirement was defined by referring to something like required retardant gallons delivered/ hour/ mile from base/ dollar. At least then, some basic economic analysis could be used to justify inventory when it comes around to contracts and budget time. What about required number of LAT sorties/ year / GACC?

Do the NICC UTF numbers actually identify requirements shortfalls? How many IMT’s don’t bother to request air support when they don’t think any air is available? UTF data would be very useful to demonstrate inventory shortfall if UTF’s represented all the unfilled need. In 2015 UTF’s represented a 10% shortfall in LAT sortie generation requirements. In 2016 UTF’s represented a 15% shortfall. Based on what I would say are very conservative UTF numbers, there has been at least a 10-15% shortfall in available LAT inventory over the last two years.

Really hard to comment on inventory objectives when it isn’t clear what the Large Air Tanker mission is. To paraphrase Lewis Carroll, if you don’t know what you want to do with them, any number will be enough.

Is the mission IA or extended attack? Is it ground support or independent tasking? What effects are trying to be achieved and how well are they achieved? Should an attack within 24 hours really be considered IA for an aircraft? CALFIRE wants aircraft on scene in 20 minutes. The Australians want <30 minutes.

Just for openers, this is a very good ops analysis piece using real data from real fires:

Our results confirm earlier research results related to LAT use and challenge a long-held assumption that LATs are applied primarily to assist in the building of line to contain fires during IA.

Perhaps most importantly, we highlight system-wide deficiencies in data collection related to objectives, conditions of use and outcomes for LAT use.

Our current inability to capture drop objectives and link specific actions to subsequent outcomes precludes our ability to draw any conclusion about the effectiveness of the federal LAT programme.

A finding in the study … Mean time of day for drops was 15:39 and only about half of the drops were IA. This makes it really difficult to say that LAT’s are there to support the ground crews.

Why not tie LAT requirements directly to the number and type of IMT’s mobilized? Perhaps some ops analysis would find a ratio of number and type of tankers to type of IMT’s mobilized? Or perhaps a ratio of days IMT’s mobilized to LAT sorties required for support? Start thinking like an integrated air-ground team and define air requirements in terms of IMT’s or crews mobilized and supported. When the definition of Head Quarters units [ IMT’s] composition or types of ground crews includes the number and type of aircraft included in support, the inventory objective for tankers will fix itself. I expect everyone has a much better handle on the amount and type of ground support required today compared to the very vague understanding of tanker requirements. Tie air requirements to the better understood ground requirements.

Once the real data gets collected and analyzed, it may be found that the best air IA assets for type 3 IMT’s aren’t fixed wing tankers. (Provided IA is redefined to something like arrival within 20-30 minutes of dispatch.)”

Another air tanker study: the use and effectiveness of large air tankers

P2V whoopup fire air tanker
Tanker 45, a P2V, on the Whoopup Fire near Newcastle, Wyoming, July 18, 2011. Photo by Bill Gabbert.

We just became aware of another air tanker study that the U.S. Forest Service commissioned. By our count this is the 13th federal study on the use of air tankers since 1995, and was one of three completed in 2013. (A list of the studies is at Wildfire Today.)

Titled Large airtanker use and outcomes in suppressing wildland fires in the United States, it was written in 2013 and published in the International Journal of Wildland Fire in February, 2014. The document maintained a low profile, possibly because it was behind the journal’s pay wall, rather than being an Open Access document.

The study attempts to determine how effective large air tankers (LAT) have been at preventing fires from escaping initial attack (IA). The authors begin by describing the poor data that they used to develop their conclusions. For example, the sparse data made it very difficult “to track drop location and time, to associate drops to specific fire events, to gather information on the fire environment (fuels, weather, terrain, etc.) at the time of the drop and, critically, to clearly identify mission objectives for each drop.”

The authors used some convoluted methods to make guesses about which retardant drops were on IA fires and which ones were not. And, “due to data availability issues” they only considered stats from two years, 2010 and 2011. In 2010 there were 19 LATs in the fleet at the beginning of the year and 14 in 2011, but by the end of 2011 the study reports there were only 10 available.

Since the air tanker fleet has atrophied from 44 in 2002  to as low as 9 in 2013, it has been impossible to always produce a LAT every time one is needed on IA. And if it does show up, the chances of it arriving while there is still a chance to slow the spread, enabling ground based firefighters to contain the fire, are not as great as they were in 2002 when there were almost five times as many air tankers.

The authors addressed the timing of air tanker drops:

Therefore, the determination of whether or not a fire will benefit from LAT drops in IA will be directly related to the delay from ignition to drop occurrence. This delay allows a fire to grow and cross a critical threshold where fireline production of IA resources cannot catch the growing fire perimeter. When evaluated in this light, the demonstrated low success rate for IA containment could be addressed by reducing the time between ignition and LAT arrival on these fires with a high potential to escape. This would require an improved ability to rapidly recognize an individual fire’s escape potential so that LATs are ordered very early in the event. Further, this suggests that if we can improve our ability to identify when and where these types of ignitions are likely to occur we should be able to effectively pre-position LATs before an outbreak of fires. If the IA success rate could be improved through such a system, overall LAT demand may be reduced because many of the evaluated drops were associated with IA fires that ultimately escaped.

And they wrote about the resistance to control of fires that receive retardant drops on IA:

That the rate of escape associated with fires that receive drops during IA is so high – far higher than the general escape rate of approximately 2 to 5% – is strongly suggestive that LAT use, when it does occur in IA situations, occurs on the more difficult fires (i.e. Category C fires as defined by Keating et al. 2012)

The “Keating et al 2012” report is more commonly known as the Rand Report.

They also make the point that although the USFS’ policy is to prioritize LAT use on IA rather than Extended Attack (EA) fires, a high proportion of LAT drops occur on EA fires.

In spite of these conditions, the authors apparently felt comfortable making the following statement in the paper’s introduction:

Results suggest that containment rates for fires receiving large airtanker use during initial attack are quite low.

A statement like that when taken out of context, or without understanding the limitations of the report’s data, can be very misleading.

If air tankers are going to be effective in IA, first they have to be near enough to the fire to arrive, preferably, within 15 to 30 minutes after being dispatched. And, they must be dispatched if not at the first report of smoke, at the first confirmation that there is a wildfire. If there is a delay until a fire officer arrives at the scene to make the decision to order aircraft, that could be the difference in effective or ineffective air tanker use.

As we have stated many times, the prescription for keeping new fires from becoming megafires is:

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

Below is a graphic that we put together showing the Unable to Fill rates for LAT requests, the number of LAT requests, and the size of the air tanker fleet since 2002.

Graph, request for large air tankers

(The chart above was revised February 3, 2015 to include data from 2014.)