The ultra-high frequency (UHF) radio infrastructure (225 MHz - 400 MHz) is used by most air navigation service providers (ANSPs) as a fundamental alternative to ensure ATC communications with non-8.33 kHz equipped State aircraft operating GAT/IFR and, in some cases to support OAT flights.
These ATC-related UHF services can be provided by civil and military ANSPs. Depending on the State’s local arrangements, military ANSPs normally provide UHF support for OAT flights whilst civil ANSPs can offer this service for State aircraft operating as GAT/IFR and OAT.
The provision of UHF or VHF 25 kHz to communicate with non-8.33 kHz equipped State aircraft is a regulatory obligation. As transcribed in section 2.3, Article 9 (12) of the SES Regulation (EU) No 1079/2012 states:
Air traffic service providers shall ensure that State aircraft not equipped with radios having the 8,33 kHz channel spacing capability can be accommodated, provided that they can be safely handled within the capacity limits of the air traffic management system on UHF or 25 kHz frequency assignments.
Member States are also required to publish the procedures to handle non-equipped State aircraft in their national aeronautical information publications (AIP).