SOPs for emergency situations must be followed by the crew, as they help to ensure a safe out come, though flight crew can modify SOPs for normal situations. if so agreed during the pre-flight briefing.

SOPs are an effective aid to decision-making for the flight crew, reducing their workload and reducing the probability of taking poor decisions and making errors.

A well-trained pilot will follow SOPs without the need to employ cognitive resources in the decision-making process, thereby maintaining the workload at an optimum level.

SOPs are presented in written form as checklists and manuals, so pilots do NOT need to store in long-term memory the correct procedure for a given situation.