Traditionally, aircraft system training is conducted by an instructor in a classroom and this approach is known as ground school theory. This approach requires trainees to attend a physical classroom with a dedicated instructor, typically active or former line pilots, for the duration of four weeks. In this approach, both new & active line pilots are required to attend the physical classroom with the instructors, titled as TRI or TRE, to get introduced with Aircraft system or to have the general subject information for recurrent training along with the Aircraft system information.

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