Correlating wildfire occurrence with aircraft use

Can crunching the numbers in the annual fire reports provide any insight about how many aircraft are needed?

Above: Tanker 912, a DC-10, drops on the Lolo Peak Fire near Florence, Montana south of Missoula. Photo by John Ames.

(Originally published at 9:39 a.m. MT March 4, 2018)

Every year the National Interagency Fire Center compiles a Wildland Fire Summary and Statistics Report. It usually runs about 70 pages and has piles of data about fire occurrence, weather, and the resources deployed. Since the number of large air tankers on exclusive use contracts has varied from 44 to 9 since 2002, (and 13 this year) an obvious question is, how many do we need? The number of Type 1 helicopters was cut in 2017 from 34 to 28, and that reduction will remain in effect this year.

These numbers do not count aircraft on call when needed (CWN) contracts — aircraft that may or may not be available when the call goes out. Since CWN vendors earn no money unless they are activated, the companies have to charge more to stay afloat. In 2017 the average daily rate for large federal call when needed air tankers was 54 percent higher than aircraft on exclusive use contracts. The hourly rate was 18 percent higher.

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

I have been discussing the data in the annual reports with one of our frequent contributors, Bean Barrett, who has taken the data analysis to a different level. Some of the key information includes aircraft requests, unable to fill (UTF) rates, and fire occurrence. We both agree that UTF information is imperfect. It is very possible that if an Incident Commander or Dispatcher knows that no air tankers or helicopters are available, they may not waste time sending in a request. Tracking these historical non-requests at this time is impossible.

And, aircraft don’t put out fires. In ideal conditions they can slow it down enough to allow firefighters on the ground to move in and actually put it out — or at least stop the spread on a section of the fire.

With those caveats, check out the work below that Bean has done, crunching the numbers in the annual fire reports. On his graph legends, “T1-2” refers to Types 1 and 2 fixed wing air tankers. If there is an “H”, it is about helicopters. Type 1’s are larger than Type 2’s.


By Bean Barrett

Maybe there is a story in the data after all as far as air tankers go. All derived from NIFC data. Not exactly ops research but perhaps useful for some insight. Like all data, this was probably measured with a micrometer, marked with a felt tip pen, and cut with an axe. So don’t take this one to the bank.

Aircraft requests and fires larger than 40,000 acres

wildfire air tanker request data

I didn’t draw in the trend line on the fires above but the number of fires >40K acres is clearly increasing [red line].  The number of fires are on the right axis in red and the number of tanker requests by type are on the left axis.

Judging from the number of requests, the response to the increasing trend in large fires has been an increasing number of requests for T1/T2 air tankers [purple line]. Seems obvious.

What isn’t obvious is why the nearly straight line increase in fixed wing requests.  Is there some kind of learning curve going on that has resulted in a steady increase in the perceived or actual value of T1-2 fixed wing air tankers? This nearly constant rate of increase in demand needs explaining and nothing in the NIFC data helps.

The requests for helos remained flat. What is curious is that there is little difference between Type 1 Helos and Type 2 helos. You would think that there would be a larger increase in requests for Type 1 helos when there is an increase in the number of big fires.

Aircraft requests and the number of significant fires

wildfire air tanker request data

This slide looks at the number of requests and the number of NIFC significant fires. Significant fires are defined as >100 acres in timber or >300 acres in grass. The number of significant fires is on the right axis in red and the number of tanker requests by type are on the left axis.

I looked at significant fires because you would think that by the time a fire got to 100 acres / 300 acres someone would be thinking about air tanker IA support. Not much of a trend in the number of significant fires.

If anything, there has been a slight decrease in helo requests over the last three years while there has been a big increase in the number of significant fires. Why doesn’t the demand for helo support follow the number of significant fires? Aren’t helos used for IA? Are the majority of helo requests not related to suppression? Why isn’t the demand for helo support reflected in the number of fires?

Not much correlation between fixed wing requests and the number of significant fires pre 2014. Better in the last 3 years. Maybe fixed wing has been more involved in IA?  However, the next slide changed my mind.

Significant fires exceeding 40,000 acres and air tanker UTF rate

wildfire air tanker request data

Since there was no NIFC data on early suppression success rates when compared to tanker availability, I made an assumption for this and the next slide. I divided the number of fires > 40K acres by the number of significant fires and assumed that percentage roughly represented the significant fires that were not successfully suppressed before they could grow >40K acres. Percentage of significant fires that grew to >40K acres is on the right axis and the UTF % for T1/2 tankers is the left axis.

Up to 2014 it looks like fixed wing T1/2 UTF rates were correlated with the percentage of fires that grew >40K acres.  [High UTF rates meant more significant fires grew >40K acres].

However, UTF rates went down for the last 3 years and were unrelated to the number of significant fires that grew >40K acres. Fixed wing availability didn’t correlate well with suppression efforts that kept significant fires from growing >40K acres. Perhaps the majority of fixed wing requests are not for suppressing significant fires.

Significant fires exceeding 40,000 acres and helicopter UTF rate

wildfire helicopter request dataThis slide might be the most important one provided someone can sort out the difference between correlation and causation. The red line is the percentage of significant fires that grew>40K acres [right axis].  The UTF rate for helo types is on the left axis.

Interpretation 1. Helo availability is THE key to more effective early suppression and preventing significant fires from turning into large costly fires. When helo UTF rates were below 20%, significant fires that grew >40K acres were at or below 1.5%.  If this is indeed a causal relationship, contract for a much larger helo fleet for IA and the huge wildfire suppression bills will come down considerably.

Interpretation 2. Helos aren’t requested until a significant fire becomes unmanageable and then a large number of requests saturate the system resulting in a high UTF rate.   I tend to discount this interpretation because [see # Requests and Significant Fires above]  total request numbers don’t go up when the number of fires go up. They don’t. Only the UTF changes. This would indicate an overall helo inventory shortfall.

Either way, there simply aren’t enough helos when they are needed. If the number of helos under contract was closer to a reasonable objective, UTF rates would not have the peaks shown above.

Bean

Only 40% of requests for Type 1 helicopters were filled on wildfires in 2017

Last year the U.S. Forest Service reduced the number of Type 1 ships by 18%.

Above: N137BH, a Sikorsky 70A or “Firehawk” helicopter, flies to refill its water bucket after dropping on the Rankin Fire in South Dakota September 13, 2017. Photo by Bill Gabbert.

(Originally published at 5:34 p.m. MT February 8, 2018)

The stats are in for the use of firefighting helicopters in 2017. The number of requests for Type 1 helicopters was close to average, but the number of orders that were Unable To be Filled (UTF) was almost double the number of filled orders. In 2017 60 percent of the requests were not filled — 220 of the 370 that were needed. That is by far the highest percentage of UTFs in the last 18 years. The second highest was 46 percent in 2012.

Type 1 helicopters are the largest used on fires, carrying 700 to 2,800 gallons.

One important change in 2017 was the 18 percent reduction in the number of Type 1 helicopters on exclusive use (EU) contract. For several years the U.S. Forest Service had contracted for 34 EU Type 1 ships, but reduced that to 28 in 2017.number type 1 helicopters firefighting order requests filled

These contracts require continuous availability throughout the mandatory availability period, which can be 180 days or more. Other helicopters may or may not be procured on a Call When Needed (CWN) contract. A CWN aircraft could be tied up on something else or undergoing heavy maintenance when the phone in the office rings asking if they can respond to a fire. And CWN aircraft cost the government much more to operate than EU resources.

These large helicopters are beloved by wildland firefighters, since they can strategically drop with pinpoint accuracy thousands of gallons of water or retardant while working close air support with ground personnel. This can cool and slow the spread of the fire, enabling crews to work nearer the fire edge. A series of water drops can enable hand crews to make steady progress on active flanks of the fire. Helicopters can often refill with water from a nearby lake or tank, making 5 to 15 minute turnarounds. A fixed wing air tanker that has to refill at an airport takes much longer.

The six helicopters that were cut last year:

  1. Prineville, Oregon (BK-1200) Swanson Group Aviation
  2. Helena, Montana (BK-1200) Central Helicopters
  3. Hamilton, Montana (BV-107) Columbia Helicopters
  4. Custer, South Dakota (BV-107) Columbia Helicopters
  5. Lancaster, California (CH-54A) Siller Helicopters
  6. Minden, Nevada (CH-54A) Helicopter Transport Services

Type 1 helicopters are frequently moved around depending on fire danger and incident activity and are often not at their home base.

What do aircraft studies recommend?

In March, 2017 when it was revealed that the six helicopters were being cut, U.S. Forest Service spokesperson Jennifer Jones explained the agency’s rationale:

At this time, the agency has determined 28 to be the appropriate number of Type 1 helicopters on EU contracts given current types and numbers of other aircraft in the fleet. This is in line with the 2012 Airtanker Modernization Strategy.

She said “Up to 30 additional Type 1 helicopters” are on Call When Needed contracts, which includes the six that no longer have EU contracts.

The Airtanker Modernization Strategydoes not make an independent recommendation on the number of helicopters or air tankers that are needed. But it refers to a study conducted from 2007 to 2009, the NIAC Interagency Aviation Strategy, which concluded that the optimum number of Type 1 helicopters on EU was 34. It also recommended a total of 35 air tankers by 2018, which included three water-scooping air tankers. At the beginning of the 2017 western fire season there were 20 large and very large air tankers on EU contracts plus two water-scooping air tankers.

fire Aviation Strategy
Table from the “2007-2009 NIAC Interagency Aviation Strategy document. Phase III”, page 21.

Our opinion

As this is being written, the politicians we elect to represent us in Washington are trying to put together a last minute (literally) federal budget that will keep the government from shutting down again tonight. They are proposing to increase the dollars spent on Defense by $165 billion. This would raise the total military budget for the next two years to $1.4 trillion. (A source in D.C. told us there is a chance the legislation will include a fix to the fire borrowing fiasco, where funds are taken from other functions to pay for wildfire suppression.)

Everyone agrees that the military needs to be adequately funded, but in 2016 the amount the U.S. spent on defense was almost equal to what the next 14 countries combined spent.

Here is an excerpt from the Washington Post, February 9, 2016:

On Tuesday, the International Institute for Strategic Studies released its Military Balance 2016 report, which seeks to examine closely the changing nature of military power. On a grand scale, the report showed – yet again – that U.S. military spending easily dwarfed the rest of the world. With a defense budget of around $597 billion, it was almost as much as the next 14 countries put together and far larger than the rest of the world.

military spending
Military spending, U.S and the rest of the world. Washington Post.

Much of the defense budget is spent in countries on the other side of the world. Meanwhile, the defense of our Homeland gets cut. Last year we saw 18 percent fewer Type 1 helicopters and the number of large air tankers was 57 percent of the recommendation in the NIAC Interagency Aviation Strategy.

Our suggestion is to prioritize the defense and protection of our citizens, homeland, forests, parks, grasslands, refuges, prairies, and wildlands FIRST, before considering spending trillions on the other side of the world.

Unable to fill requests for air tankers increased in 2016

In 2016 there was an increase in the percentage of requests for large air tankers that went unfilled, increasing from 10 percent in 2015 which was the lowest since 2009, to 13.4 percent in 2016.

Counting the U.S. Forest Service HC-130H air tanker there was a maximum of 21 large and very large air tankers on exclusive use contracts in 2016. However, the two Erickson MD-87 aircraft were not available for most of the year due to problems with the retardant system. The company claims they have fixed the issue and they should be ready to go this summer. A few other call when needed (CWN) large and very large air tankers were activated for weeks at a time in 2016. Unless new contracts for CWN air tankers are issued that will be effective this year, the number of available air tankers in 2017 should be about the same. A new exclusive use contract is expected to be in effect in 2018.

Tanker 12 Trailhead Fire
Tanker 12 on the Trailhead Fire. A Cobra helicopter is in the background. Photo July 1, 2016 by Matthew Rhodes.

The number of acres burned in the lower 49 states (which excludes Alaska) was virtually the same in 2015 and 2016, with both being pretty close to average. There were also few extended fire sieges involving multiple large fires occurring at the same time that required a high number of air tankers. Having the fires spread out over time minimizes the number of air tanker requests that go unfilled.

wildfire acres per year
The number of acres burned in wildfires in the lower 49 states (excludes Alaska).

Here are some of the Unable to Fill numbers we computed from the data reported by the National Interagency Fire Center for 2016:

  • Type 1 and 2 large air tankers: 13.4%
  • Single Engine Air Tankers: 21.1%
  • Type 1 helicopters: 12.3%
  • Type 2 helicopters: 8.6%
  • Type 3 helicopters: 8.3%

There were only seven requests for MAFFS air tankers, and all were filled.

Air tanker availability during this wildfire season

Air tanker availability during this wildfire season

T-131 in hangar door
Coulson’s Air Tanker 131 being pushed out of the hangar at McClellan Air Force Base in Sacramento, March 21, 2014. Photo by Bill Gabbert.

Today two newspapers published lengthy and detailed articles about the shortage of large air tankers. The Missoulian’s has an emphasis on their home-town company, Neptune Aviation, while the Arizona Republic’s has several references to last year’s Yarnell Hill Fire in Arizona that killed 19 members of the Granite Mountain Hotshot crew. You will recognize the names of one or two of the people quoted in the articles.

Below are the introductory paragraphs:

Missoulian:

Wildfire season officially begins April 28, and the U.S. Forest Service is heading into it with only three modern firefighting air tankers.

Missoula-based Neptune Aviation has one of those planes on contract. It argues to have two more, but competitors won a protest over Neptune’s no-competition award worth almost half a billion dollars over 10 years. By August, Neptune will have two more jets looking for work.

“We’re still cranking out air tankers,” Neptune CEO Ron Hooper said Friday. “But that’s the state of limbo we’re in. We’re waiting to see what the Forest Service will do.”

Meanwhile, one of Neptune’s six Korean War-vintage P2-V bombers saw seven hours of flying time on a wildfire in New Mexico last week. Of the five companies that received Forest Service “next-generation” contracts to provide seven new fire bombers last year, three have failed to deliver their planes.

Arizona Republic:

National wildfire officials are urgently trying to reinforce an undersized and aged fleet of retardant-dropping air tankers in the aftermath of June’s deadly Yarnell Hill Fire, but as they gird themselves for a potentially treacherous 2014 season, significant improvements may be more than a year away.

Tom Harbour, national director of fire and aviation management for the U.S. Forest Service, said drought conditions have dried up the West since last summer, when monsoon rains spawned a bumper crop of fire fuels.

“You bet we’re concerned and worried about what’s going to happen,” Harbour told The Arizona Republic. “This puts us in a precarious position as we head into this new season.”

Harbour noted that numerous unusual winter wildfires already have erupted and been doused in Arizona’s Tonto National Forest and in drought-ravaged Southern California. State officials said on April 2 that 179 wildland fires already had been reported this year in Arizona alone.

The significance: “We could be off to a very early start,” said Harbour.

The Arizona Republic and USA Today are both credited with this video report, uploaded Saturday to YouTube, about air tanker shortages:

Air tankers available in 2014

The following Type 1 & 2 air tankers, commonly called “large” air tankers, will be available on exclusive use contracts this year:

  • 8 — on the “legacy” contract, (1 Minden P2V, 6 Neptune P2Vs, and one Neptune BAe-146)
  • 2 — on the “next-gen” contract (1 Coulson C-130H and a 10 Tanker DC-10)
  • Possible: 5 other next-gen aircraft that received contracts on May 6, 2013 that may or may not become certified. The companies that still have not supplied the aircraft are Minden, Aero Air, and Aero-Flite.

Total: between 10 and 15. This does not include the two Neptune air tankers that were issued the sole source contract. That contract was protested, and the protest was upheld by the Government Accountability Office. The U.S. Forest Service can also call upon up to eight MAFFS military C-130 aircraft and can borrow some old CV-580s from Canada and Alaska if they are available. One additional DC-10 is on a call when needed contract and may be available if needed by the U.S. firefighting agencies.

Requests for air tankers that were unable to be filled

We have read several references recently about the number of requests for air tankers by wildfire incident commanders that were unable to be filled (UTF). We have been reporting on this issue for several years and updating it annually, but just to be sure the latest data is out there, below, again, is a graphic we put together from National Interagency Fire Center reports. The UTF numbers do not include the requests that were canceled, contrary to what you may have read elsewhere.

Air tanker unable to fill requests (UTF)

The actual numbers for the last three years:

UTF data 2011-2013

Almost half of requests for air tankers were not filled in 2012

New data that the National Interagency Fire Center released about the 2012 wildfire season reveals that almost half, or 48 percent, of the requests for large air tankers could not be filled. Of the 914 requests, 438 were rejected as “unable to fill” (UTF), meaning no air tankers were available to respond to the fire; 67 were cancelled for various reasons. The requests that were filled included 346 for civilian contracted air tankers and 63 for military Modular Airborne FireFighting Systems (MAFFS) C-130s.

For additional perspective, consider that the number of requests for air tankers during the 2000 fire season was higher than the 13-year average between 2000 and 2012 — 548 requests vs. the average of 434, but in 2000 only 7 percent of them were UTF. In 2000 there were 40 large air tankers on exclusive use contracts compared to between 9 and 11 in 2012.

More acres burned in the United States in 2012 than average. At 9.3 million, it was the most since 2007. But the number of fires was surprisingly small, only 67,774 which is the lowest number since 2005.

The average number of fires in the lower 49 states each year is gradually decreasing, but the average size is increasing rapidly. This could be due to a number of factors, including climate, increased fuel loading (vegetation), reduced budgets, fewer firefighters, and not as many air tankers.

Average size of fires lower 49 states through 2012

One of the reasons the U.S. Forest Service has allowed the air tanker fleet to atrophy may be a misguided attempt to save money. Fast, aggressive, initial attack on new fires can reduce the number of megafires that may burn hundreds of homes while costing the taxpayers tens of millions of dollars in suppression costs alone. The 2002 Federal Aerial Firefighting Report, usually known as the “Blue Ribbon Panel Report”, addressed this issue:

While cost-saving is an essential contracting criterion, it appears to have displaced other, less-quantifiable criteria that call for more judgment and experience, such as value, safety records, and past performance. Pilots have sarcastically referred to this cost-focus philosophy as “budget protection” rather than “fire protection.” In contrast, a Canadian philosophy states, “We can’t spend too much the first day [of a fire],” seems to justify spending money on early containment of a fire, and doing so in an operationally effective way that minimizes the number of escaped fires. In the long run, the Canadians believe that they spend far less for a quick-response capability designed to contain small fires than they do to fight fires after they grow large.

It has has been 1 year, 2 months, and 24 days since the U.S. Forest Service issued a solicitation for next-generation large air tankers, but no contracts have been awarded.