FSS will consider an aircraft overdue how many minutes past ETA?

The appropriate time frame used by Flight Service Stations (FSS) to consider an aircraft as overdue is 30 minutes past the estimated time of arrival (ETA). This standard protocol is in place to ensure adherence to safety practices and allow sufficient time for potential delays that might occur during a flight, such as weather conditions, air traffic control issues, or other unforeseen events. After this time period has elapsed without any communication from the aircraft or updates on its status, FSS will initiate procedures to locate the aircraft, which may include notifying search and rescue agencies.

The 30-minute threshold is strategically determined to balance the need for safety and quick response without prematurely categorizing all aircraft that may be delayed for legitimate reasons as overdue. This practice reflects the understanding that various routines and operational factors can affect flight schedules, making the 30-minute mark an essential indicator for concern regarding a flight's safety.