id: 5.2-on-guard-procedures title: 5.2 On Guard Procedures meta: Air Traffic Controller on guard procedures to be followed. order: 2 #
5.2 On Guard Procedures #
Tip
: When opening a frequency, Controllers must{.red} allow time for things to settle; for example, do not “on guard” aircraft on short final, allow the aircraft to land and complete the rollout uninterrupted
5.2.1 #
Controllers must{.red} always check what frequency the aircraft is tuned into before sending an “on guard” message in case they are with another tower/radar facility. Radar Controllers should{.red} also be aware of an aircraft’s active/away status (see 6.6.5 below). Below is a summary of when “on guard” procedures are applicable, aircraft must not{.red} be “on guarded” outside of these limits:
| Facility | Vertical and Lateral Limits |
|---|---|
| Tower | SFC - 10,000ft AAL and within 25nm |
| Departure/Approach | SFC - 18,000ft AAL / FL180 and within 50nm |
| Center | SFC - FL600 and within the white boundaries |
If the airport elevation is deemed significant, Controllers may elect to take this into account (e.g. with an airport elevation of 5000ft, Controllers may adjust the “on guard” altitude/FL by 5000ft/FL50 respectively)
5.2.2 #
Aircraft should{.red} be given a reasonable amount of time to tune into the frequency after being “on guarded” and must not{.red} be “on guarded” if on another active frequency.