Definition
An FAA Advisory Circular titled 'FAA Approval of Aviation Training Devices and Their Use for Training and Experience,' which sets out the criteria the FAA uses to approve Aviation Training Devices (ATDs) and explains how pilots and instructors may use those devices to meet certain training and recent flight experience requirements.
Plain English
It is the FAA document that says which ground-based training devices are officially approved, and what kind of pilot training and currency credit you can earn by using them.
Context Anchor
Seen in discussions about using flight simulation training devices or aviation training devices during pilot training.
Derivation
An 'Advisory Circular' is the FAA's standard format for non-regulatory guidance that explains how to comply with the regulations. The number '61-136' identifies it as guidance related to 14 CFR Part 61 (certification of pilots and instructors), document number 136 in that series.
Why Pilots Care
It is the document that determines whether time logged in a particular training device counts toward a certificate, rating, or instrument currency. Without it, hours in an ATD are just practice; with it, they can be loggable and creditable.
Intuition Check
Do not read advisory as unimportant. An Advisory Circular is not usually a regulation by itself, but it explains an FAA-accepted way to follow the rules.
Example Sentence 1
The flight school's Redbird simulator is approved under AC 61-136, so students can log a portion of their instrument training time in it.
Example Sentence 2
Training providers reference Advisory Circular AC 61-136 when submitting a new flight training device for FAA evaluation.