Definition
An FAA Advisory Circular that explains the causes, characteristics, and hazards of aircraft wake turbulence and provides recommended pilot procedures for avoiding it during takeoff, landing, and en route flight.
Plain English
An official FAA guidance document that tells pilots how wake turbulence behaves and how to stay clear of it.
Context Anchor
Seen in FAA training material when discussing wake turbulence avoidance, especially during takeoff, landing, and operations near larger aircraft.
Derivation
An Advisory Circular (AC) is the FAA's standard format for non-regulatory guidance. The numbering system groups documents by subject area: the 90-series covers air traffic and general operating procedures. So 'AC 90-23' simply identifies it as the 23rd document in that subject series.
Why Pilots Care
Following its guidance helps pilots maintain safe separation distances and reduce the risk of sudden loss of control from another aircraft's wake.
Intuition Check
“AC” does not mean air conditioning or alternating current here. In this FAA context, it means Advisory Circular: an official FAA guidance document.
Example Sentence 1
The instructor referenced AC 90-23 when explaining why we should rotate before the point where a preceding heavy jet lifted off.
Example Sentence 2
AC 90-23 outlines the recommended spacing intervals for different aircraft categories to avoid wake encounters.