The skies over Europe are in danger of future accidents unless co-operation and compatability can be secured between contradicting air traffic control centres across the continent.
An overhaul of European air traffic control systems is necessary to avoid further disasters.
In the wake of the recent German air disaster, the on-going dissection of evidence and proportioning of blame highlights the rifts and inadequecies of air traffic control systems in charge of European skies.
Investigations have shown that as well as receiving contradictory instructions just before the crash, the Russian pilot may have been flying by rules different from those followed in the rest of Europe.
Contradictions in flight rules put passengers at risk
A lethal grey area has emerged in the aftermath of last week's mid-air collision over Lake Constance in Germany. Evidence has surfaced that suggests that both pilots were acting in a way they had been told was correct.
European officials insist that international rules oblige pilots to follow the orders of their onboard systems, the aircraft collision avoidance system (Acas), and ignore conflicting advice from air traffic control.
Control Center of the swiss air traffic control Skyguide.
But Russian officials this week insisted that their pilots were expected to consider both the orders of air traffic control and onboard systems, before making their own decision.
A directive set out in an International Civilian Aviation Organisation (ICAO) document stipulates that in the event of a clash between the instruction given by air traffic control and a high-level alert from the onboard Acas system - known as a resolution advisory - 'the pilot should follow the resolution advisory'.
"The performance-based training objectives were sent out to all states by an ICAO state letter in 1997. The Russians will have received the ICAO guidance," said John Law, the project manager for the Acas system at the European air traffic control centre, Eurocontrol.
But his version of the rules was challenged by Yuri Tarshin, the head of the department of aviation standards at the Russian ministry of transport.
"Russian aviation companies who fly in Europe do so under European rules," Mr Tarshin said.
"In European rules for training of pilots, you can find nowhere where it says what is the priority.The decision is up to the main pilot. He has to take into account all the information, particularly when there is a resolution advisory."
"We follow the European standards of the countries in whose airspace we fly. If we had a document saying that the pilot should, in any case, obey the signals of the Acas, then we would follow it. But that document does not exist."
MEP's bid to consolidate European airspace plans
These revelations come in the same week that European Parliament ministers met to discuss plans for making incompatible air traffic control systems communicate with each other, creating a single view of European airspace.
A single European sky may help to avoid inconsistencies in policy.
The Single European Sky project is designed to improve air safety, reduce costs and minimise delays by ensuring consistent operating practices between the 64 different national air traffic control centres across the continent by using a new satellite-based air traffic management system that will carry the seamless exchange of flight information.
The plans will be in place by 2004, but no deadline for implementation has been set.
'Outdated' European air control in need of reform
'The proposal for a single European sky is an ambitious attempt to reform the outdated architecture of European air traffic control. It comes at a time when new positioning and communication technologies offer opportunities for significant improvements in the efficiency and safety of air travel,' said Loyola de Palacio, European Commissioner for Energy and Transport.
Eurocontrol, the European air safety organisation, has been working with the EC to define systems and architectural guidelines, and will play a vital role in enforcing the initiative.
All European air traffic controllers will have to ensure compliance. In the meantime, air travel safety will remain a lottery.