Components are identified by specification numbers, manufacturing numbers, material numbers, manufacturing design part numbers and owner identification numbers. Many manufactures have identified design part numbers as material numbers while some airline owners assign their own number to the design part numbers. Knowing which is which and what is interchangeable can save a lot of work. Even within design part numbers there are interchangeability approved by the Production Authorization Holder (PAH) and the regulatory authority. It is our job at Sonico to record interchangeability when found to aid in performing maintenance service for our customers. It is why turn times are often less at Sonico than from other maintenance sources. Even within the expendable parts there are vast interchangeability options that can reduce turn times for repair from weeks to days.