What type of mission typically involves a predetermined duration for firing?

The type of mission that typically involves a predetermined duration for firing is a suppress mission. This type of operation is designed to keep enemy forces at bay for a specified period, allowing friendly forces to maneuver or carry out other operations without facing immediate fire. The emphasis on a set timeframe in a suppress mission differentiates it from other firing missions like adjust fire, which focuses on refining target coordinates or effects rather than adhering to a strict firing duration. Immediate suppression is often more reactionary based on immediate threats, and FFE (Fire For Effect) is primarily concerned with delivering a significant weight of fire rather than maintaining it over a predetermined time frame.