"(a) At aerodromes having no notified ground radio frequency a VHF frequency is available to assist pilots to avoid potential
collisions between arriving and departing aircraft. Pilots may use this frequency to broadcast their intentions for safety
(b) The frequency assigned is 135.475 MHz and is known as 'SAFETYCOM'.
(c) The conditions of use are: (i) SAFETYCOM shall only be used at aerodromes having no notified ground radio frequency. If a VHF frequency is notified for a location, that notified frequency must be used even outside the notified operating hours.
(ii) Transmissions shall be made only within a maximum range of 10 nm of the aerodrome of intended landing, and below 2000 feet above the aerodrome elevation.
(iii) SAFETYCOM shall only be used to transmit information regarding the pilot's intentions, and there should be no response, except where the pilot of another aircraft also needs to transmit his intentions or, exceptionally, has information critical to the safety of an aircraft in a condition of distress or urgency.
(iv) Phraseology is to comply with the requirements of CAP 413 (Radiotelephony Manual) Chapter 4 Section 6. (v) SAFETYCOM is not to be used for the conduct of formation flights unless landing at or taking off from an aerodrome for which no other frequency is notified and within the limits specified at sub para (ii)
. (vi) Pilots operating at aerodromes without a notified frequency are recommended to use SAFETYCOM, but its use is not mandatory. However, if pilots choose to use it, they must make the transmissions listed in CAP 413 as 'essential'. It must not be assumed that all other pilots in the vicinity are monitoring the frequency and, as at all other times, pilots must maintain a good lookout.
(vii) No air traffic service is associated with SAFETYCOM. Where an aerodrome lies within controlled airspace, pilots must establish contact with the responsible air traffic services unit, and obtain clearance prior to entering controlled airspace.
(viii) Information transmitted on SAFETYCOM confers no priority or right of way. Pilots shall comply with the Rules of the Air Regulations, including the provisions in relation to avoiding aerial collisions."
The above is extracted from the UK AIP, GEN 3.4.3 which should be referred to in case of doubt.