Barry D. Smith profiles how the US Marines Corps fights fires in California using helicopters and tiltrotors
With over 125,000 acres of range land, wildfires are a common occurrence at Camp Pendleton Marine Corps Base in Southern California, US. In addition to the base’s fire department, US Marine Corps (USMC) helicopters are used to fight these fires. They can also be called upon to assist local civilian fire departments during large wildland fires throughout southern California.
The USMC uses the CH-53E Super Stallion, the UH-1Y Huey and the MV-22 Osprey aircraft models to fight these fires. Squadrons of these helicopters based at Camp Pendleton and Miramar Marine Corps Air Station, located a short distance from Pendleton, rotate firefighting duty on a monthly basis. They use underslung water buckets filled from a lake, pond, or other source to drop on the fire. Depending on which aircraft used, the buckets can hold from 320 up to 900 gallons (1,450 to 4,090 l) of water.
All three types of aircraft are equipped with forward looking infrared (FLIR) turrets, which the crews use to see through the smoke to locate firefighters on the ground and see exactly where the fire is located. In addition, the pilots can also see other aircraft better with the FLIR. Use of all available sensors makes operations safer and more effective with better situational awareness.
Pilots report that the performance of the UH-1Y helicopter has been outstanding during the fires. The UH-1Y has a 4,000-pound (1,800-kg) maximium load on the cargo hook; a full 320-gallon water bucket weights about 2,500 pounds.
all three types of aircraft are equipped with forward looking infrared turrets
“We usually took about a 90-per-cent fuel load, which left us with a comfortable power margin,” commented Major Jeff Barnes, a UH-1Y instructor pilot. “Some of the major lessons we learned is that using the Bambi Bucket is not like other external load operations. In firefighting operations, we have a constant load that reaches 25 ft below the aircraft and changes weight by 2,500 pounds when we fill and release the water. So, it takes a different mindset where we have to be aware of how that bucket and load affects the aircraft performance at all times. It is very dynamic.”
The Osprey uses a 900-gallon bucket – thanks to its high lifting capacity, the crews can carry a full load of fuel and still be below maximum weight. Because of the amount of rotor downwash with the MV-22, a 130-ft (40-m) cable is used between the bucket and the aircraft to prevent the proprotors from fanning the flames (the length of cable used for standard sling loads would be just 10-20 ft). The fact that the bucket is significantly lower than the aircraft is a factor when the pilots are manoeuvreing close to the ground, requiring a little more piloting skill and finesse during the fire missions. More power and time is needed to slow down and make turns – any quick movements will cause the load to pendulum and pull the aircraft off the intended flight path.
Each Osprey squadron averages three trained crews, which is six pilots and nine crew chiefs. They can train more personnel as they perform actual firefighting missions, as long as there is at least one pilot and one crew chief qualified on the fire mission in the aircraft.
The CH-53E Super Stallion also uses the 900-gallon water bucket, which doesn’t even put it close to its maximum load carry capacity. The pilots say the firefighting mission is not all that different from their regular military role; they do a lot of external load work with the 53 at low altitudes, doing the weight management and power calculations.
Fire runs involve members of the crew taking the lead at different times, explained Barnes: “I put together a class to teach crews how to fly firefighting missions and I made a comparison to a WWII bomber crew. The pilots get the aircraft to the target and then hand over the ship to the bombardier to fly the bomb run and release the bombs. That is what we do on fire missions. The crew chiefs in the cabin have much better visibility than the pilots as the aircraft comes over the fire and are the ones that actually drop the water.”
He continued: “When we are coming into a dip site to get water, they are calling out any obstacles and tell us how low to go to get the bucket in the water. When we are dipping out of lakes, they also watch for civilian boats that might get too close and be damaged or sunk by our rotor downwash. The pilots can’t see the bucket, so the cabin crew tells them where the bucket is in relation to the ground and any obstacles and when they are clear to fly away from the dip site.”
any quick movements will cause the load to pendulum and pull the aircraft off the intended flight path
The situation is reversed while flying to the fire, said Barnes: “En route to where the aircraft is going to drop the water, the pilots will paint a picture of the drop area for the cabin crew as they can’t see forward as easily as the pilots can. … There is a constant conversation between the pilots and cabin crew to co-ordinate their efforts to get the water on the fire. When we drop the water we are typically flying at about 50 knots with the bucket about 50 ft above the ground.”
Due to the large size of the base, Camp Pendleton has a mutual aid agreement with CAL FIRE, the state civilian firefighting agency. Any major wildfire will bring CAL FIRE air and ground resources onto the base. CAL FIRE has a helicopter co-ordinator position that usually flies in a light helicopter from a local law enforcement or fire agency. Called the MILCO, or military helicopter co‑ordinator, he/she assigns the military helicopters their drop missions and does airspace co-ordination so they don’t conflict with civilian helicopters and air tankers working on the fire. The MILCO helicopter will also act as the communications relay between the civilian air and ground firefighting forces and the military helicopters.
Talking with several pilots, they say the difficult part is integrating into the civilian system working with the firefighters on the ground. They will review those policies and techniques more often in the classroom setting. On an actual fire, they usually arrive and shut down to talk with the firefighters on the ground before starting to drop water. They also have the command and control aircraft that tells them where to drop and what the aircraft traffic pattern over the fire is.
“The biggest challenge I see is the congested airspace with many aircraft operating in a small area with degraded visibility due to the smoke,” explained one pilot. “So, situational awareness is key. We also have to make sure we aren’t pressing too hard. We want to save people’s homes, but we have to take a step back every once in a while to make sure we don’t compromise on safety.”
The crews continue to work with CAL FIRE and expand and increase their training opportunities and expertise. For example, they have training exercises with CAL FIRE representatives on the ground giving them guidance and advice on drop techniques and procedures. This also improves air-ground co-ordination during a real fire. In addition, they help the Marines with set up, break down, and troubleshooting the water buckets.
“It was a great experience and I look back on it as one of my favorite things I have done as a Marine pilot,” commented Captain Donald Carlsen, a CH-53E pilot. “You are doing something good for your community as well as doing something you don’t normally get to do. Overall, it is a very satisfying mission. This mission is very similar in concept to what we do as Marine aviators. Our main mission is the support the Marines on the ground however we can. When we are fighting fires, our job is to support the firefighters on the ground by delivering loads of water how and where they need it. So, it fits our normal mission profile like a glove.”△