Category B - Aerial Application: Aircraft, Drift, and Communication
What Category B Tests
Category B (Aerial) covers fixed-wing and rotorcraft applications in Minnesota. The exam emphasizes aircraft setup and calibration, nozzle and droplet management, drift and inversion awareness, swath spacing, flagging or GPS guidance, loading and emergency procedures, and communication with ground crews and neighbors. Questions often combine weather, aircraft setup, and label buffer requirements.
Aerial rules and concepts
- Calibrate before each major change in product, nozzle, pressure, or speed; flow rate, swath width, and application height must match the label and aircraft.
- Smaller droplets increase coverage but raise off-target drift risk; use droplets coarse enough for the product and conditions.
- Wind speed and direction are only part of drift risk: temperature inversions, humidity, and aircraft wake vortices matter.
- Maintain label buffer zones; do not spray when a sensitive area is immediately downwind unless the label allows it and conditions are safe.
- Use flaggers or accurate GPS guidance, and keep communication between pilot, loader, and ground crew.
Worked example
A pilot plans to treat a field 60 feet from a sensitive crop. Wind is 6 mph toward the sensitive crop, and the forecast suggests a temperature inversion. The label requires a 100-foot buffer. What is the defensible decision? Reasoning: wind speed alone is under many thresholds, but the 100-foot label buffer is not met, and an inversion can hold fine droplets and move them unpredictably. Delay or redesign the application. Do not assume a higher application height or lower pressure fixes a buffer violation; verify nozzles, droplet size, and guidance, and document the no-go decision.
Traps
- Believing higher pressure always improves coverage.
- Using GPS as a substitute for label buffers and visual site checks.
- Ignoring inversion risk on calm, clear evenings.
- Turning downwind at the end of a swath without considering drift.