A Deep Dive into ATPCO Fare Rules: Understanding Category 5

For any travel professional involved in fare construction, understanding ATPCO categories is crucial. A common area where mistakes are made is in Category 5, which covers Advance Reservations and Ticketing. Airlines often mistakenly file bytes 64-67, which can lead to fares being priced incorrectly when an advance purchase was intended. ## Key Concept: Exception Time (Bytes 64-67) The "Exception Time" field within Category 5 is used to indicate that ticketing requirements are only applicable if reservations are made by a specific time. This field is a **match field**, meaning the rules in the associated table will only apply if the reservation time matches the Exception Time. This is an exception to normal rule processing. When the Exception Time is coded and matched, the system must either pass or fail based on that table alone; it cannot read on to any other tables in the string. This makes correct filing critical to ensure your advance purchase fares are not offered outside of their intended window.