Definition
The three wedge-shaped areas that make up a Terminal Arrival Area (TAA) on an RNAV (GPS) approach. Each sector is bounded by two radials extending outward from the initial approach fix or intermediate fix, and each one publishes its own minimum safe altitude for arriving aircraft within that wedge.
Plain English
The arrival area around an RNAV approach is divided into three slices, like cutting a pie into three pieces. Each slice has its own safe altitude printed on the chart. Whichever slice you fly into tells you how low you are allowed to go before joining the approach.
Context Anchor
Seen on RNAV instrument approach charts that use Terminal Arrival Areas, especially when selecting the correct arrival sector before joining the approach.
Derivation
The phrase comes from the everyday image of a pie cut into wedges. The TAA design uses that familiar shape because each sector radiates outward from a central fix, just like slices radiating from the center of a pie.
Why Pilots Care
Understanding the sectors lets pilots select the correct minimum altitude and routing when joining an approach from any direction without losing obstacle protection.
Analogy
Think of the chart area like a pie cut into slices. Your airplane’s position determines which slice you are in, and that slice tells you which instructions apply.
Intuition Check
Do not read “pie-shaped sectors” as a casual drawing description only. In this context, each slice is a defined part of the arrival procedure with specific instructions attached to it.
Example Sentence 1
Approaching from the northeast, the pilot identified which of the three pie-shaped sectors the aircraft was in and descended to the published minimum altitude for that wedge.
Example Sentence 2
Each pie-shaped sector lists its own minimum altitudes so pilots know exactly how low they can safely fly while inside it.