Plain English Meaning
An official FAA letter that says, 'You are allowed to do this specific thing under these specific conditions.' For a simulator, the LOA is the paperwork proving the device has been checked and approved for training use.
Full Definition
A formal written approval issued by the FAA that grants a specific person or organization permission to conduct an activity, use a device, or follow a procedure that would otherwise require a different form of certification or approval. In the flight simulation training device context, an LOA is the document the FAA issues to qualify a particular simulator or training device for use in pilot training, testing, and checking, specifying what credit the device may be used for and under what conditions.
Context Anchor
Seen when a flight school, instructor, or evaluator checks whether a simulator or training device is approved for a specific training use.
Derivation
From 'letter' (a written document) and 'authorization' (official permission). The phrase is plain English, but in FAA use it carries a specific regulatory weight: not just any letter, but a formal approval document with legal effect.
Why Pilots Care
Determines whether time spent in a simulator can be credited toward ratings or currency requirements.
Intuition Check
Do not read “letter” as casual correspondence. In this context, a letter of authorization is an official FAA approval document that controls what is allowed.
Example Sentence 1
Before starting the lesson, the instructor checked that the simulator's LOA was current and covered instrument approach training.
Example Sentence 2
Training completed without a current LOA cannot be logged toward certificate requirements.