Concept for UAV air tanker

In December, 2009, Wildfire Today covered a patent application filed by John A. Hoffman for an air tanker, in the form of an unmanned aerial vehicle (UAV), that would be transported by a mother ship and released near the fire. It would then be piloted remotely from either the mother ship or from the ground, and after dropping retardant on the fire, would land to reload, or might be a single use aircraft and would be “destroyed in the release step”. In the latter case the UAV would be “possibly constructed of frangible material so as to crash into the fire area”.

NitrofirexThanks to a comment by Jerome on a recent article here about FAA approvals for the use of UAVs, we are now aware of a similar concept, this time by Nitrofirex, which appears to be based in Spain. Much more information is available about the Nitrofirex system than Mr. Hoffman’s idea.

Multiple Nitrofirex UAVs would be transported in a large mother ship and released through the rear cargo door. The folded wings would deploy and the aircraft would glide autonomously to the target then “automatically and with great precision” release the water or retardant. The small engine which had been idling would power the ship back to the tanker base where it would be reloaded and inserted back into a mother ship.

According to the company the system could also be used:

  • “To combat a nuclear, biological or chemical emergency
  • To act on meteorological phenomena.
  • To combat pests or to spray crops in remote or inaccessible areas.
  • For night time fumigation of drug plantations.”

We were not able to find any specifications about the aircraft regarding retardant capacity, speed, range, or cost.

Nitrofirex screen grab
Nitrofirex UAV air tankers. Screen grab from the video.

Assuming that the cost, firefighter safety, and design issues are solvable, the only portion of the concept that troubles me is the assumption that an air tanker could, without a pilot either on-board or at a remote location, effectively drop retardant in the exact location where it was needed and at an appropriate height above ground. In flat terrain over a slow-moving fire this might be possible, but in mountainous areas it would be a challenge. Especially if a “squadron” of them were released at the same time.

What if…. an orbiting aircraft or a ground-based firefighter a safe distance away had a laser designator which the UAV could use as a target? Much like the military does for smart bombs and missiles. Terrain-following radar such as that used in the F-111C could make the drops more accurate and effective.

The company has developed a video which explores the UAV air tanker concept.

11 thoughts on “Concept for UAV air tanker”

  1. Bill,

    A few thoughts:

    Laser designators don’t work very well if there is smoke and dust in the target area. The laser spot that the UAV guides on would be obscured unless the spot was upwind of the burn [probably not where you want to drop]. Right now, until things change, GPS guidance is the way to go, coordinates are fed to the UAV by the aircraft prior to drop.

    Today’s UAV designs wouldn’t carry any more than a SEAT does. Liquids are the heaviest bulkiest things to carry. More liquid payload = bigger UAV = bigger engine = more fuel for the UAV = larger cost, and so goes the design and engineering spiral.

    Getting a TFR [temporary airspace restriction] designation for the entire flight path of the UAV would be a problem. So far, the FAA doesn’t let UAV’s get mixed in with regular flight traffic. Returning to the airport is a big problem. UAV certifications are in the works but mixed traffic is a ways off.

    Still, an interesting concept especially for night operations. It fits right in with a prime reason to use UAV’s … too dangerous for manned flights to do routinely.

  2. Why can’t we just continue to let manned flights handle this? It’s got to be cheaper, safer and more flexible. Not to mention a good job for good Americans. Also let’s not forget the many times an air asset gets reassigned in the middle of a fire to save some folks getting overrun. Many of the jobs we want UAV’s to take over could be handled with current aircraft, that are much much much cheaper by the way, and can be deployed today without any changes in laws or policies. There are plenty of trained Americans that would love the chance to fly on some fires, patrol our borders and keep watch over our cops and look for bad guys. I for one kind of want a pilot flying over my cities and over me on that fire.

  3. I dont see how this would be helpful with the large scale fires we have. costly…ineffective…cant get to the target in the right window of opportunity…boots on the ground not birds in the sky

  4. Hi,
    I agree with all previous comments.

    How about fighting fires at dawn!
    Just when earth is cooled, wind is calm. Early morning until noon is the best window to get it done.
    How many times Tankers are sent when the wind picks up mid afternoon…

    So before spending millions in “unmanned” stuff, let’s review and improve some procedures for better efficiency.


    1. Good points, Jerome. Too often incident management teams do very little if any firefighting at night when it’s much easier to accomplish some direct fireline construction. And like you say, early in the morning is a good time as well. If an IMTeam decides to not fight fire at night, they should at least have firefighters on the fireline 30 minutes before sunrise. They can accomplish a hell of a lot more at 5 a.m. than at 5 p.m. If this concept, including the use of aircraft early in the morning, had been followed on Day 2 of the Station fire, we would not still be writing stories about that debacle. And there might be fewer Government Accountability Office investigations.

  5. Max, I have a little experience flying using night vision goggles … in my opinion … it would be very impractical to consider any night air tanker operations with manned aircraft in mountainous terrain. Over a prairie grass fire, maybe. The problem is that by the time you get low enough to do the job at night in the mountains, you have no safety margin for terrain avoidance. If you fly high enough for a safety margin, the suppressant dispersion is excessive. If you use FLIR instead of goggles, you still have a significant problem with terrain avoidance. It would take an extremely sophisticated, EXTREMELY expensive FLIR with a radar aided terrain avoidance system coupled with an automated payload delivery system to enable effective night air tanker operations.

    Thats why I think that if you have to do night operations, UAV’s might be a long term answer.

  6. Bean,

    Until then (UAV’s might be a long term answer…) what do we do??
    R&D is important but actual situation is too…


  7. Jerome,

    In the near term, the only manned aircraft that might be able to do the work at night are helos. They have the advantage of slow speed over the ground and time to negotiate terrain. The problem with using helos at night is the extensive training required and the training flight time necessary to maintain currency with night vision devices, not to mention the equipment expense.

    The whole firefighting air tanker effort already suffers from a significant lack of finances and political support. Adding the night helo capability is technically possible but would be a very expensive capability in a system that is already bankrupt.

  8. Now, night blimp operations could be very possible. They could fly slow and low and make it rain along the perimeter all night.

  9. Bean; valid points about Copters at night. I believe San Diego county is experimenting it.

    Blimps; come on… is that a priority , invest in blimps? at night?
    747 or DC10 could drop at 500 feet or higher radio altimeter.. Same as blimps…

  10. Thanks to everyone for the comments and analysis included with the article. In the Nitrofirex team we are used to this kind of doubts prior to know the complete concept and the numbers behind our project. Economically attractive, technically feasible and the perfect complement for the daylight manned resources in order to provide 24h aerial firefighting capability.

    Copters during night, 747… we can discuss about the efecctiveness and the feassibility of those concepts.

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