Civil aviation regulators are highlighting that certain European Union procedures for radio communication failure, due to take effect from 1 May, are not being adopted in the UK.
The EU published an amendment in April last year detailing the procedural revision.
But the UK Civil Aviation Authority states that “no changes” are being made its own regulations, and says air traffic services personnel should be alert to the possibility that crews might mistakenly follow EU procedures within UK airspace.
The CAA says there will be three main differences between the UK and EU procedures for radio communication failure.
Under the EU rules, should the crew of such a flight operating under instrument rules encounter visual conditions – opts to continue flying visually – they will set a transponder code of 7601, rather than 7600. The aircraft label for flights transmitting a 7601 code will not flash on UK situation displays.
If the crew in EU airspace has lost radio contact the aircraft will maintain last assigned speed and level – or minimum safe altitude, if necessary – for 20min after setting the 7600 transponder code, unless flying a standard instrument arrival or departure pattern. In the UK this period is 7min.
A flight in the EU which has been directed to proceed offset using area navigation, without a specified limit, will rejoin the last received and acknowledged route no later than the next significant point. But in the UK it will continue in accordance with air traffic instructions last acknowledged for 3min only, and then proceed to rejoin the flightplanned route as directly as possible.
According to a CAA safety notice on the changes, issued on 14 March, air traffic personnel should familiarise themselves with the differences.
The notice says that current guidance on radio communication failure procedures is “sufficient to ensure the new EU procedures pose no additional risk” to aircraft operating within UK airspace.
ICAO is developing new internationally-standardised procedures for communication failure, complementing lost-link procedures for remotely-piloted aircraft, and the CAA says it is supporting this work, expecting the ICAO provisions to be effective from November 2028.
