The Cyprus government is urging international aviation bodies to raise pilots' awareness of a potentially dangerous air traffic control anomaly in the eastern Mediterranean, especially as a significant recent political development may make the situation worse.

The risk to aviation safety stems from the fact that there is no direct communication between the two adjacent air control centres at Ankara and Nicosia, so there is no advance co-ordination of aircraft crossing from one flight information region (FIR) to the other.

The anomaly is politically based, resulting from the fact that the northern part of the island remains illegally occupied by Turkey since its invasion in 1974. Tensions have now been heightened by the 18 April election in northern Cyprus of the hardline separatist candidate Dervis Eroglu.

In 2007, the European Commission criticised Turkey for failing to co-operate with Cyprus on ATC matters. It said "the lack of communication between air control centres in Turkey and the Republic of Cyprus compromises air safety". Now the prospects for a solution have almost certainly receded as a result of Eroglu's election, Nicosia ATC says.

At present, aircraft approaching Nicosia FIR are required to "establish contact with Nicosia ACC in order to pass essential flight details...10 minutes before entry". But when aircraft cross the Ankara/Nicosia FIR boundary, they are directed by Ankara to change frequency directly to the illegal area control at Ercan, the main airport in northern Cyprus.

So southbound aircraft entering Nicosia airspace have to communicate with both Ercan and Nicosia. Problems arise either when aircraft fail to contact Nicosia 10min before reaching the boundary, or accept flight-level changes or flight plan diversions within the FIR from Ercan, without consulting Nicosia.

In 2009 there were 461 incidents reported. Of these about 50 involved pilots accepting level or heading changes from Ercan. In a recent incident, Ercan cleared an aircraft to descend towards Beirut and change to the Beirut control frequency. The pilot obeyed the instruction. Beirut, meanwhile, assumed the pilot had been released by Nicosia, but Nicosia could not contact the aircraft despite the fact that it was still well inside its FIR.

Charis Antoniades, head of Nicosia Area Control, says: "Double-controlling is very dangerous. Pilots are not expecting this interference. At a time of heavy workload it puts extra strain on controllers as well as pilots. Sometimes the pilots get confused about which station is speaking to them and which is the legal one."

Source: Flight International