Plain English Meaning
A formal written approval from the FAA that says, 'You are allowed to do this specific thing, under these specific conditions.' For training devices, it confirms which simulator can be used and what training credit it qualifies for.
Full Definition
An official document issued by the FAA granting a person or organization permission to conduct a specific activity that would not otherwise be allowed under standard regulations, or specifying conditions under which a particular operation, device, or training program may be used. In flight training, a letter of authorization commonly approves the use of a specific flight simulation training device for credit toward pilot certification or currency requirements.
Context Anchor
Seen when discussing FAA-approved use of flight simulation training devices in training programs.