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Dī´vʉrs´ - Chatham County Mosquito Control Air Unit’s Differing Services

Posted 7 years 232 days ago ago by Admin

If I mention Chatham County, Georgia, you might well ask, “Where’s that?” If I say Savannah, you most likely know the location. The coastal city is well known for its Southern charm and rich American history that draw tourists from all over the world—who often go searching for Forrest Gump’s famous bench.

Savannah and surrounding Chatham County is a community on the water. Not only does the Savannah River run through the county, but the Atlantic Ocean abuts its eastern shore, while swamps and tidal estuaries abound. All this H2O creates a unique problem for the county, its visitors, and residents. It’s the perfect breeding ground for mosquitos—lots and lots of them.

As you will see, the team at Chatham County Mosquito Control (CCMC) takes its job of controlling that pesky population very seriously. I was surprised at how the science of insect control intersects with helicopter operations. Furthermore, CCMC’s diverse aviation operations go well beyond mosquitoes, as they serve county residents and tourists in many valuable and cost-effective ways.

Why Use Public Resources To Control Mosquitoes?

The answer to that question can be summed up in two words: Commerce and Disease. On the commerce side, over a million visitors per year vacation and do business in Savannah and its surrounding areas. Tourism generates big revenue. If the mosquito population is allowed to thrive, being a tourist in the area will probably not be much fun. Not only would all those flying insects make life annoyingly miserable, they could also endanger health. This brings us to that D-word—disease. Mosquitos can transmit many viruses and parasites. Eastern Equine Encephalitis, West Nile virus, malaria, and the recent disease du jour, Zika, are just a few of the illnesses they can carry. So protecting the public, livestock, and other animals is an important facet of CCMC’s mission.

How do they carry out that mission? There are three broad tasks that CCMC engages in battling mosquitoes: Surveillance, Prevention, and Eradication. Believe it or not, helicopters are used for all these tasks, as three MD 500 helicopters, one Air Tractor airplane, three pilots, three mechanics, and a variety of specialized equipment all combine to do battle.


During the surveillance phase, first the geographic area is broken into approximately 300 target sites where mosquitoes are known to hatch. The sizes of these breeding sites range from relatively small to as large as 5,000 acres. All sites combined are well over a million acres. Still, they all have one thing in common—water. The water may come from various sources, including rainfall dredging, and tidal fluctuations, but wherever it comes from, the insects lay their eggs near it. Even mud makes for inviting mosquito motels. As the Savannah River is dredged to maintain shipping lanes, millions of yards of river-bottom muck is removed to large containment areas. As that mud dries and cracks, the water remaining in those cracks become a red-light breeding district for the fertile fliers.

As the surveillance stage continues, the three MD helicopters fly field personnel on reconnaissance missions to determine the size of the larvae population. These agents scoop up water samples and manually count individual larva. When a certain threshold is exceeded, a larvicide attack is ordered.

However, it’s not enough to merely know how many larvae are in a sample. Mosquito control also needs to know if the mature mosquitoes the larvae become are carrying disease. That’s when fixed-wing assets are called upon—chickens. Yes, even chickens valiantly serve in the mosquito wars. They don’t volunteer; they’re drafted, and then put in cages and transported to mosquito sites. There they are bitten. Next, blood samples are taken to determine if any disease is present.


Mosquito prevention, or larvicide, occurs before the enemy can mature into flying adults and disperse. As with surveillance, helicopters play a vital role. Once a larvicide mission is ordered, a granular weapon is created using a larvicide mixing plant (Sand Hog) to mix sand with a very specific quantity of liquid growth-inhibiting hormone that only impacts mosquitoes. The Sand Hog rig, a truck mobile unit staffed by mechanics in the aviation department, follows the helicopter to the battleground. There the larvicide is loaded close to the action, reducing ferry and flight time. The granular product is pumped into an Isolair 4500-500E broadcaster mounted on the helicopter. Once airborne, the broadcaster rains down a dose of death.


The eradication side of mosquito control is known as adulticide, which is the good old-time method of killing flying mosquitoes with spray. Despite their best efforts, the CCMC knows they cannot prevent all larvae from maturing. So they proactively spray where there are complaints of high mosquito populations, including areas populated by humans. I was somewhat shocked when we flew right over a Walmart shopping center while spraying adulticide, but if the goal is to keep people from being bitten, then you often must spray where the people are. However, it’s not a surprise air raid—except for the mosquitoes. Prior to any scheduled adulticide spray mission, the CCMC publishes a community notification 24 hours in advance. This gives those who may be impacted negatively by the spray application (for example, beekeepers) time to prepare.

Helicopter are the preferred method of active adulticide spraying in order to penetrate heavy tree canopy, be more precise (surgical), and is most always done at dusk when mosquitos are most active. A spray system, which was custom designed by CCMC staff, is installed on the helicopter and the solution is loaded at the hangar base prior to flight. Once on location, an Ag-Nav Guia GPS precision guidance/tracking system is used to provide the pilots with swath/lane guidance, documentation to avoid flying overlapping lanes, and to use the minimum amount of adulticide needed (Minimum Label Rate).

The spray system operates at 1,000 pounds per square inch and pushes the adulticide out of the system through externally impinged PJ20 misting nozzles with .020-inch orifices. This unique design gives CCMC precisely sized droplets for mosquito control, while at the same time reducing the impact to non-target organisms. The pilots typically fly at 100 to 110 knots airspeed at 200 to 300 feet, using 1,000-foot lanes when spraying.

Mosquito control missions make up approximately 90 percent of the flying the unit does. It can be demanding and “at risk” work that often occurs in low altitude environments that put aircraft very near obstacles like towers, antennas, and even some structures. Doing it at (or even after) dusk adds additional complexity to the job. Training and high levels of situational awareness are extremely important for safe operations.

More Than Mosquitoes

Savannah has many activities that put residents and tourists in or on water. For example, downtown Savannah has several water taxis, gambling boats, and dinner boats in action at all hours of the day and night. The river is tidal and there is almost always a steady 8-knot current moving in or out of the city. A worst-case scenario for the community would be a large passenger boat sinking and putting many victims into the water at once.

Fortunately for county residents and visitors, CCMC Chief Pilot Scott Yackel was not satisfied merely doing mosquito control. He believed the skill sets of the CCMC team, and its uniquely capable aircraft, could provide additional services. “Since mosquito control activities occur during specific windows of time, there are other times during the day and night when we could be available for other missions, such as search and rescue, law enforcement, and firefighting,” said Yackel.

While Rotorcraft Pro was on location for this story, CCMC underwent a joint training exercise with the Georgia Search and Rescue Swift Water Rescue Team (GSAR), made up of personnel from fire rescue departments from the surrounding region. So CCMC has become part of the emergency action plan designed to handle situations like a capsizing ship.

Water Rescue

During such a sinking ship scenario, the objective is to rapidly deploy dozens of rescue swimmers into the water to assist victims until they can be pulled from peril by helicopters or rescue boats. With training and practice, dozens of rescue swimmers can be deployed in a matter of minutes, and victims can be pulled from the water shortly thereafter. Rescue swimmers first assemble on the beach in mask, fins, and with personal flotation devices. Four swimmers at a time are then picked up by helicopter. They position themselves on externally mounted SWAT seats while the helicopter flies to the victims. The swimmers then deploy from the helicopter that hovers 10 to 15 feet above water.

Once all rescue swimmers are in the water and assisting victims, the helicopter returns to the beach, where a tactical flight officer installs on the aircraft a bellyband, short haul line, and a rescue ring for plucking victims from the water. In the event a victim cannot get into the rescue ring, the pilot may elect to descend and dip the skid into the water so that a crew member can pull the victim up onto the SWAT rack, and then into the helicopter. This is not the preferred method, but it is an option.

Law Enforcement

Assisting law enforcement is another area that CCMC can handle. Local and state law enforcement agencies are very aware of CCMC’s capabilities, and they frequently request assistance when aerial assets are needed. One might think that an aircraft designated for fighting mosquitoes might not be suited for fighting crime. However, CCMC’s MD helicopters are set up with a modular nature so that they may be quickly reconfigured between various missions. In very short order, an aircraft can be reconfigured to a fully capable law enforcement helicopter ready for night missions. Current law enforcement capabilities include a:

  • SWAT racks.

  • ANVIS 9 night vision goggles.

  • Aero Computer flight mapping system.

  • SX-16 searchlight.

  • FLIR 8000 infrared imaging system with microwave downlink.

When a law enforcement support request comes in, CCMC partners with the Savannah-Chatham Metropolitan Police Department (SCMPD) to provide them with tactical flight officers trained in law enforcement operations by the CCMC.

More Capabilities

CCMC’s mission capabilities even go beyond mosquito control, rescue, and law enforcement. Because much of the county is surrounded by Mother Nature’s bounty, wildfires can light up when things get dry. CCMC crews can have the MD helicopters reconfigured with a Bambi Bucket and on location for a fire in very short order with the Airtractor 402 providing fixed-wing drops.

Finally, the unit also participates in a program called Project Lifesaver. Certain people in the community prone to getting lost, such as Alzheimer patients and some autistic children, wear special tracking wristbands. When one of them goes missing, the helicopter launches with special equipment that allows the missing person to be located. EMS and/or law enforcement can then be directed to their location.

With all the services they provide, I think the Chatham County Mosquito Control aviation unit should change their name, maybe to the Chatham County Airborne Service Unit, with the key word being “Service.” Although Yackel understands his unit’s primary mission is mosquito control, that’s not how he closes our interview. “The goal of our operation is to serve our citizens, whether it be mosquito control, search and rescue, firefighting, or law enforcement. Our citizens are the ones we want to protect.” It’s his hope that when a resident looks up and sees CCMC’s bright yellow helicopters overhead, they feel like they are getting their money’s worth in the form of service.

Based on my 25 years of experience in the helicopter industry, I can attest that they are.

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