Definition
A standardized RNAV instrument approach layout in which the initial approach fixes (IAFs), the intermediate fix (IF), and the final approach course are arranged in the shape of a T. The IF sits at the center, with two IAFs positioned on either side at roughly 90 degrees to the final approach course, and the final approach course extends straight ahead to the runway. This layout supports terminal arrival area (TAA) procedures and gives pilots a consistent, predictable structure for transitioning from the en route phase into the approach.
Plain English
A common shape used for modern GPS-style approaches, where the routes into the approach form a T. The crossbar of the T gives the pilot two side-entry points, and the stem of the T is the straight-in path to the runway.
Context Anchor
Seen on RNAV instrument approach charts and in Terminal Arrival Area discussions, especially when deciding which charted entry area and altitude apply to your arrival.
Derivation
Called a T design because the chart layout literally looks like the letter T — two initial fixes forming the top bar, and the final approach course forming the vertical stem down to the runway.
Why Pilots Care
Provides predictable entry paths that reduce workload and allow smoother transitions from en route navigation to the approach.
Grounding Statement
Picture the runway at the bottom of the T: aircraft can arrive from the left, right, or top, then all flow down the same stem toward landing.
Intuition Check
Do not read “basic” as “easy” or “less important,” and do not read “T” as an aircraft tail shape. Here, Basic T design means the standard T-shaped layout of an instrument approach arrival area.
Example Sentence 1
The RNAV approach into the field uses a basic T design, so we'll pick the IAF on the left side of the T since we're arriving from the northwest.
Example Sentence 2
ATC cleared the flight direct to the initial approach fix in the Basic T design, allowing an immediate descent to begin the approach.