GPS typically switches from terminal to approach mode when the approach is activated and the aircraft is about 2 NM before the final approach waypoint/FAF, depending on the GPS unit and procedure setup.

Typical sequence

  • En route : wider CDI sensitivity, usually 5 NM full-scale.
  • Terminal : the GPS enters this phase around 30 NM from the airport after an approach is loaded/armed, with CDI sensitivity narrowing to about 1 NM full-scale.
  • Approach : once the approach becomes active, the GPS changes to approach sensitivity; many references describe that as happening about 2 NM before the FAF/FAWP, then tightening further toward final approach sensitivity.

Practical rule

A good rule of thumb is: terminal mode is for arrival planning, approach mode is for the final segment. In many IFR GPS units, you arm the approach before the 30 NM point, then the unit switches into approach sensitivity near the final approach fix rather than immediately at 30 NM.

Important nuance

Different avionics can phrase the transition slightly differently, and some units use labels like “arm,” “active,” or “suspend” for the approach sequence. The exact behavior depends on the GPS model and whether the approach is LNAV, LPV, or another type.

In one line

Terminal to approach usually happens when the approach becomes active, often about 2 NM before the FAF, not simply at the 30 NM terminal boundary.