The Precision Guided Suppression Unit (PGSU) is a new tool for Aerial Firefighting. It’s an advanced technology and not an understatement to say it will be met with unfounded fears initially. It’s Human to mistrust new technology, the recent AI environment is a case in point.
Even though the PGSU is made with Commercial Off the Shelf (COTS) products, the net result is something “next generational” for the Wildland Firefighting community that it’s closer to a Military Grade tool. The PGSU is complicated technology to be sure, and its engineering encompasses many different technical disciplines.
The PGSU is many things, but there are some things the PGSU is not. We’ve learned that the Wildland Fire Community speaks a similar language to the Military but misunderstanding of military terms and how they apply to this technology leads to a “Mythology” that permeates a technology and can ultimately lead to its non-use.
Myth Busting; the PGSU is:
Not for “Close Air Support” of Firefighters
The PGSU is meant to be used directly on/into flame/fire. Ground Firefighters shouldn’t be close enough to the hottest parts of the fire, which is the target, but only repeated accuracy will determine what that minimum “stand-off” distance will need to be for them. For now, it’s meant to reach the places Firefighters can’t or shouldn’t.
Not a Munition
The PGSU is not a munition of any type. It’s not Bullet; it’s not spin stabilized for straight line accuracy. It’s not an Artillery Shell; it has winglets and is guided using gravity and airspeed and is not an unguided projectile. It also is not an Artillery Shell or Bomb in a damage causing sense; it has no internal energetics and does not cause fragmentation or “Shrapnel.”
Note: Shrapnel refers to the flying metal pieces or fragments scattered by an exploding bomb, shell, mine, or bullet. These sharp shards fly at high speeds and are intended to cause wounds or damage. The PGSU doesn’t produce shrapnel.
Not Intended for Indirect Attacks
It is not meant for use with Long-Term Retardant (LTR), and not a “defensive” or Indirect Attack tool. It could probably deploy Retardant, but that puts the PGSU at a disadvantage. LTR is heavier and thicker than water, not intended to be used on flame, and requires much more than 105 gallons to be effective. It’s also not intended to be atomized, which defeats one of the major tactical advantages the PGSU provides.
Does Not “Explode” in the Fire
When the PGSU deploys its water, it doesn’t “explode” or “air-burst” above the ground. The “air-burst” that occurs when the water deploys, creates more of an instant “cloud” in the fire. It’s accomplished through quickly “pressing” water, in 18 separate chambers, through 18 fixed nozzles, to produce a cloud. Air Burst implies the PGSU “explodes” in an uncontrolled fashion to get this effect; the inflators and nozzles ensure this is a directed, contained, and intentional event. This control is also why the PGSU doesn’t create shrapnel.
Not Uncontrolled
It is unmanned and is “dropped” like a cargo load with a parachute, but it is very much in control of itself, so it flies with purpose, under guidance. Once it achieves any vertical airspeed (from gravity) or airflow over the airfoils, it “seeks” the relative wind. It does not fall freely to the intended deployment point, it flies to it. If the computer determines it can’t for some reason “fly to the target” anymore, an automatic or manual initiated Emergency Abort process is initiated.
Not a Glider
The PGSU is approximately 1,000 lbs. fully loaded, and it flies at high speeds. Why can’t it be designed to fly slower and perceivably safer like a glider? Because if it were more like a glider, its larger wings would make it more susceptible to turbulence, and a fire puts off a ton of turbulent air. This turbulence is “defeated” with speed; speed with maneuverability. The PGSU has winglets that are designed for high-speed flight; it’s a key component in achieving Precision by design.
Not Comparable in Coverage Levels
Measuring effects in Coverage Levels, a metric Wildland Firefighters are familiar with, is like comparing apples and oranges. This technology is a Direct Attack tool and needs to be measured in heat-exchange metrics (BTUs). Coverage Levels are determined by dropping a liquid from an aircraft and measuring how much lands in cups laid out in a grid. Atomization of the water with the PGSU means an unknown amount of payload is lost and would never have landed in a cup to begin with. The PGSU isn’t intended to “cover ground,” it’s far more surgical than that. Coverage Levels also hint at Indirect Attacks, not Direct Attacks on flame.
Not a Replacement Tool for Anything
The PGSU is a “next generation” tool, but it’s just that, another tool for consideration. It has the mission of attacking flame directly, but it can’t replace the thousands of gallons a fixed source or Engine can bring to the fight. It’s expected its effects will slow or stop fire, but the Wildland Firefighter will always be needed to ultimately extinguish it. It may provide a tactical solution to a given fire problem if used currently and may develop into its own tool eventually. From the CoE’s perspective, until we can develop the safety protocols, learn actual effectiveness in the field, and develop the doctrine around its use, it will continue to be a tool never used.
Not Effective
We simply can’t answer this, yet. Prime Minute continues to make large leaps between versions and test iterations, and have made incredible strides to date. You could say they’re moving at the speed of their product; Terminal Velocity. Precision will come, and that’s definitely the first ingredient; we have to put the water in a position to measured against fire. Once we use some PGSUs on Scheduled Fire and can take some measurements, we will be closer to answering this. We can already hypothesize that it will be effective, we need to measure how effective.
About the Author:
LTC (Ret) Tony Somogyi is the Aviation Projects Manager at the Center of Excellence for Advanced Technology Aerial Firefighting. Tony joined the CoE in 2025 after a Helicopter EMS Pilot career with CareFlight of the Rockies. He’s a Master Army Aviator, former Army Instructor and Maintenance Test Pilot, and former Commander of the Army’s High-altitude Aviation Training Site (HAATS) in Colorado.
