AOPA Pilot Magazine - April 2015 - 68

case 911 dispatchers call to ask if they are
spraying. "People new to the county often
call 911 when they see the DC-3s, because
we fly so low-they think we are about to
crash," he chuckled.
LCMCD'S FLEET of aerial applicators today
bears a slight resemblance to the thunderous
bug bombers of the past. For one, the C-47s
and their burly radial engines are gone.
They were replaced more than a decade
ago with Dodson International Turbo
Dakota DC-3TPs, with twin 1,230-shafthorsepower PT-6A-65AR turbines turning
whisper-quiet Hartzell five-blade, fully
reversible propellers. As reliable as they
have been, a trio of Beech King Airs slated to
replace the -3s sit in LCMCD's hangars. The
newer aircraft feature machined-on-site
external belly tanks and ultra-low-pressure
spray systems capable of producing the tiny
25-micron Diabrom droplets required to kill
adult mosquitos.
The Dodson -3s have integral chemical
tanks positioned aft, but they've been retrofitted with wing-mounted pods, completely
external (Diabrom is extremely corrosive-
you don't want it on your airplane or your
skin). The new dispersion system requires
no in-flight pilot intervention, thanks to
LCMCD pilot and resident inventor Gene
Sutton. About a decade ago Sutton pushed
hard for adaptation of the AG-Nav graphical mapping interface into LCMCD aircraft.
He and Lai Nguyen, chief technologist for
AG-Nav, wrote and rewrote the box's Linuxbased software and designed the interface to
the spray and granular dispersion hardware.
There was a lot of trial and error. Ultimately,
the system was refined to its current rendition, and all that testing gave birth to a
state-of-the-art aerial application system.
Larvae inspectors can order a flight, but
most complaints come from homeowners.
A truck drives the prescribed area at night
and collects a sampling of mosquitos that
are counted, sexed, and segregated by species. If the count supports the complaint, an
adulticide night run is scheduled. The scientist defines the areas to be sprayed using
polygons drawn over Google Earth. The
program takes forecast wind into consideration and calculates the chemical drift, too.
68 | AOPA PILOT April 2015

The pilots arrive and open the polygon
files on their flight-planning computers.
They refine the plan, linking adjacent spray
areas into one large spray area (long runs are
preferred), then set up waypoints to the initial spray box and beyond. All is downloaded
to a USB key, then uploaded into the aircraft
AG-Nav GUIA guidance system, which provides moving-map navigation and obstacle
awareness to and from the spray sites. It also
switches on the autospray, and guides the
pilot along each row with a light bar that is
accurate to within a few feet.
"I don't know that the GUIA makes it
any easier to fly a straight line, but it certainly makes it easier to verify that you
didn't fly a straight line!" O'Neal said.
The autospray is integral to the system,
turning off the spray at the end of each row
and restarting it at the beginning of the next
row. Get too far off a row or out of the spray
box? The autospray shuts off, protecting nospray zones. Need to exclude an area in the
middle of your spray box? Autospray will
take care of that, too. New software even
corrolates the volume of application to aircraft groundspeed.
The result is reduced pilot workload.
"They can focus on flying and accuracy now,
and it shows," O'Neal said. "Our tracking is
downloaded at the end of each mission,
for the scientists and administrators. Now
we can see better how accurately we have
applied the chemicals and then compare
that to the kill."

TECHNICIANS count mosquitos
under the microscope to verify
complaints before spraying can
be ordered. Mosquito larvae are
treated with varying conconctions
in the lab (above). Chicken blood
is screened weekly for distinct
RNA signatures that indicate
mosquito-borne disease is present
in the county (right).
AOPA Pilot Magazine - April 2015

Table of Contents for the Digital Edition of AOPA Pilot Magazine - April 2015
