What activity is prohibited with ATP aircraft?

Defueling is prohibited with ATP aircraft primarily due to safety and regulatory considerations. When working with aviation fuel, handling procedures are tightly regulated to prevent accidents that could result from fuel spillage, fire, or environmental contamination. The aircraft is typically designed for fueling and safe operation, but defueling operations can pose greater risks, particularly when it involves transferring fuel from one tank to another or when dealing with potential contaminants.

It’s important to note that fueling, routine inspections, and pre-flight checks are essential and standard maintenance practices that ensure aircraft safety and compliance with aviation regulations. Thus, while routine operations and checks are necessary for safe flight operations, defueling under certain circumstances is restricted to enhance safety against hazards associated with fuel management.