When must pilots wear the label-required personal protective equipment during pesticide application?

Pilots are required to wear the label-required personal protective equipment (PPE) during pesticide application while making nozzle adjustments to ensure their safety and minimize exposure to potentially harmful chemicals. This requirement is critical because nozzle adjustments may expose the pilot to chemical mist or drift, particularly as they are making changes that could affect how the pesticide is being applied. Wearing PPE during this phase of operation protects the pilot from inhalation or skin contact with pesticides, which can be hazardous to health.

In contrast, wearing PPE is not commonly mandated only during takeoff or landing, as these phases typically do not involve the handling or application of pesticides. Furthermore, handling pesticides on the ground, although requiring PPE, does not pertain specifically to the act of pesticide application which occurs during flight, thus making it less relevant in the context of the question. Therefore, the emphasis on wearing PPE during nozzle adjustments directly relates to ensuring the pilot's protection while engaging in the aerial application process.