Definition
Optional extensions to the straight-in initial approach segment of a Terminal Arrival Area (TAA), used when terrain, airspace, or procedure design requires the straight-in entry zone to reach farther from the airport than the standard TAA boundary allows. They appear on instrument approach charts as extended portions of the straight-in TAA segment beyond the normal 30 NM radius.
Plain English
An extra-long stretch added to the straight-in arrival area of an instrument approach, so pilots coming from farther away can still join the approach directly without flying around to a different entry point.
Context Anchor
Seen in RNAV instrument approach and TAA discussions, especially when identifying the left, right, or straight-in area before joining the approach.
Derivation
"Departure" here is used in its geometric sense — a line departing from a point — not as in aircraft takeoff. The segment "departs" outward from the standard TAA boundary, so it is called a departure extension.
Why Pilots Care
Knowing a departure extension exists tells you that you can join the straight-in segment from farther out than the usual 30 NM TAA radius, which affects route planning, descent planning, and where you expect to begin the approach.
Intuition Check
Do not read departure here as a runway takeoff. In this context, it means a line going away from an approach fix and extended outward to help define an area.
Example Sentence 1
The chart showed a departure extension on the straight-in TAA segment, so we joined the approach from 40 NM out instead of repositioning.
Example Sentence 2
Chart review showed departure extensions added to the TAA to cover runway 09 departures.