AERIAL APPLICATION EVALUATION EXAMS 2025/2026
QUESTIONS AND ANSWERS RATED A+
✔✔What are examples of application equipment malfunction and how should the pilot
prepare? - ✔✔Ruptured hoses or lines, tank leaks, pump failure, nozzle/valve leaks,
and electronic controller failure. Prepare by locating possible places to jettison the
pesticide load or immediate landing points. Do not operate the aircraft over people or
animals during a leak
✔✔Are pesticide labels required to be at the application site? - ✔✔Aerial application is
exempt from this rule as long as the pilot maintains radio contact with the ground crew
and flaggers
✔✔Differentiate off-target movement from pesticide drift - ✔✔• Off-target movement
occurs post-application due to weather, site, and chemical factors. Highly persistent and
volatile pesticides with low absorption potential are more prone to off-target movement
• Spray drift, as defined by the National Coalition on Drift Minimization (NCODM), is the
movement of pesticides through the air during application, including vapor or droplets
that concentrate in an inversion layer during application
✔✔Define "driftable fines" - ✔✔Pesticide droplets smaller than 150-200 microns, which
are highly prone to drift. Droplets smaller than 50 microns remain suspended in the air
indefinitely or until evaporation
✔✔For a nozzle with a Volume Median Diameter (VMD) of 400, what percentage of
droplets will be less than 400 microns in diameter? - ✔✔50%
✔✔Define the three physical properties of a spray mixture that have a significant effect
on droplet size in aerial applications - ✔✔• Dynamic surface tension: adjuvants change
the normal surface tension of droplets over time, causing larger droplets to split during
spraying. Most adjuvants (except spray drift control) reduce dynamic surface tension,
creating smaller droplets
• Extensional viscosity: the amount a droplet stretches as the pump forces the mixture
through the nozzles, affected by the amount of pressure in the system. Higher pressure
lowers viscosity, producing smaller droplets
• Shear viscosity: a liquid's resistance to flow
✔✔List the 8 color spectrum categories, along with their symbol and color code - ✔✔•
Extra Fine (XF): purple
• Very Fine (VF): red
• Fine (F): orange
• Medium (M): yellow
• Coarse (C): blue
• Very Coarse (VC): green
• Extra Course (XC): white
, • Ultra Course (UC): black
✔✔Define an inversion layer and explain how it affects application - ✔✔An inversion
layer forms when the crop or soil is cooler than the air above it, creating a very stable
layer of air that prevents vertical movement and suspends small droplets for hours if not
the entire night. Do NOT spray during an inversion. Inversions occur during calm winds
with little air mixing, generally before sunset and lasting into early morning or near
bodies of water
✔✔Define evaporation as it relates to aerial application and explain how weather
conditions lead to it - ✔✔• Droplets exposed to air will begin to evaporate and shed their
water/dilution carriers, making the droplets smaller. Evaporation becomes more rapid at
higher temperatures, lower humidity, higher wind speeds, and further distance from
discharge to target. Water-based carriers evaporate faster than oil-based carriers
• Applying early in the morning generally reduces evaporation conditions (lowest
temperatures, highest humidity, and lowest wind speeds), though temperature inversion
risks are greater
✔✔Define co-distillation as it relates to aerial application and explain how weather
conditions lead to it - ✔✔Co-distillation is caused by pesticides contact very hot
surfaces, usually soil without vegetation. Rapid evaporation and fog can pick up the
product and move it off-site
✔✔Define thermals as they relate to aerial application and explain how weather
conditions lead to them - ✔✔Thermals cause upward air movement that entraps and
moves small droplets, increasing the probability for off-site drift. Thermals are caused by
the ground heating up, usually in the afternoon, and especially after cool nights, causing
air near the ground to rise
✔✔Define and list methods to reduce wind shear effects that cause smaller droplets -
✔✔Wind shear, for aerial applications, is the difference in aircraft speed and droplet
speed upon exiting the nozzle, and how relative wind interacts with the spray.
Appropriate airspeed selection and nozzle orientation, including consideration of:
• Selecting nozzle types to produce large droplets
• Orienting nozzles backwards relative to flight direction
• Increasing pump pressure at higher airspeeds to reduce the difference between nozzle
exit speed and relative wind speed
• Using spray drift control adjuvants
• Droplets tend to be smaller at high airspeeds
✔✔What are elements of a liquid dispersal system? - ✔✔A pump, a tank/hopper, hoses
and lines, control valves with suck-back features (vacuum to prevent nozzle drip), a
pressure gauge, booms, and nozzles
QUESTIONS AND ANSWERS RATED A+
✔✔What are examples of application equipment malfunction and how should the pilot
prepare? - ✔✔Ruptured hoses or lines, tank leaks, pump failure, nozzle/valve leaks,
and electronic controller failure. Prepare by locating possible places to jettison the
pesticide load or immediate landing points. Do not operate the aircraft over people or
animals during a leak
✔✔Are pesticide labels required to be at the application site? - ✔✔Aerial application is
exempt from this rule as long as the pilot maintains radio contact with the ground crew
and flaggers
✔✔Differentiate off-target movement from pesticide drift - ✔✔• Off-target movement
occurs post-application due to weather, site, and chemical factors. Highly persistent and
volatile pesticides with low absorption potential are more prone to off-target movement
• Spray drift, as defined by the National Coalition on Drift Minimization (NCODM), is the
movement of pesticides through the air during application, including vapor or droplets
that concentrate in an inversion layer during application
✔✔Define "driftable fines" - ✔✔Pesticide droplets smaller than 150-200 microns, which
are highly prone to drift. Droplets smaller than 50 microns remain suspended in the air
indefinitely or until evaporation
✔✔For a nozzle with a Volume Median Diameter (VMD) of 400, what percentage of
droplets will be less than 400 microns in diameter? - ✔✔50%
✔✔Define the three physical properties of a spray mixture that have a significant effect
on droplet size in aerial applications - ✔✔• Dynamic surface tension: adjuvants change
the normal surface tension of droplets over time, causing larger droplets to split during
spraying. Most adjuvants (except spray drift control) reduce dynamic surface tension,
creating smaller droplets
• Extensional viscosity: the amount a droplet stretches as the pump forces the mixture
through the nozzles, affected by the amount of pressure in the system. Higher pressure
lowers viscosity, producing smaller droplets
• Shear viscosity: a liquid's resistance to flow
✔✔List the 8 color spectrum categories, along with their symbol and color code - ✔✔•
Extra Fine (XF): purple
• Very Fine (VF): red
• Fine (F): orange
• Medium (M): yellow
• Coarse (C): blue
• Very Coarse (VC): green
• Extra Course (XC): white
, • Ultra Course (UC): black
✔✔Define an inversion layer and explain how it affects application - ✔✔An inversion
layer forms when the crop or soil is cooler than the air above it, creating a very stable
layer of air that prevents vertical movement and suspends small droplets for hours if not
the entire night. Do NOT spray during an inversion. Inversions occur during calm winds
with little air mixing, generally before sunset and lasting into early morning or near
bodies of water
✔✔Define evaporation as it relates to aerial application and explain how weather
conditions lead to it - ✔✔• Droplets exposed to air will begin to evaporate and shed their
water/dilution carriers, making the droplets smaller. Evaporation becomes more rapid at
higher temperatures, lower humidity, higher wind speeds, and further distance from
discharge to target. Water-based carriers evaporate faster than oil-based carriers
• Applying early in the morning generally reduces evaporation conditions (lowest
temperatures, highest humidity, and lowest wind speeds), though temperature inversion
risks are greater
✔✔Define co-distillation as it relates to aerial application and explain how weather
conditions lead to it - ✔✔Co-distillation is caused by pesticides contact very hot
surfaces, usually soil without vegetation. Rapid evaporation and fog can pick up the
product and move it off-site
✔✔Define thermals as they relate to aerial application and explain how weather
conditions lead to them - ✔✔Thermals cause upward air movement that entraps and
moves small droplets, increasing the probability for off-site drift. Thermals are caused by
the ground heating up, usually in the afternoon, and especially after cool nights, causing
air near the ground to rise
✔✔Define and list methods to reduce wind shear effects that cause smaller droplets -
✔✔Wind shear, for aerial applications, is the difference in aircraft speed and droplet
speed upon exiting the nozzle, and how relative wind interacts with the spray.
Appropriate airspeed selection and nozzle orientation, including consideration of:
• Selecting nozzle types to produce large droplets
• Orienting nozzles backwards relative to flight direction
• Increasing pump pressure at higher airspeeds to reduce the difference between nozzle
exit speed and relative wind speed
• Using spray drift control adjuvants
• Droplets tend to be smaller at high airspeeds
✔✔What are elements of a liquid dispersal system? - ✔✔A pump, a tank/hopper, hoses
and lines, control valves with suck-back features (vacuum to prevent nozzle drip), a
pressure gauge, booms, and nozzles
