Final answer:
A "Depart TDY/SD/ TCS" NCOER is required when an NCO departs on Temporary Duty, Special Duty, or a Temporary Change of Station and they have been under a rating official's supervision for 90 or more days.
Step-by-step explanation:
A "Depart TDY/SD/ TCS" NCOER (Non-Commissioned Officer Evaluation Report) is a type of performance evaluation in the U.S. Army. It becomes mandatory when a Non-Commissioned Officer (NCO) departs on Temporary Duty (TDY), Special Duty (SD), or a Temporary Change of Station (TCS) when they have been under the direct supervision of the rating official for 90 or more calendar days. This NCOER is used to document the performance and conduct of an NCO during this specific period before they leave for the new assignment.