UK pilots are pressing the Government and European Union regulators to provide assistance to carriers crippled by the volcanic ash crisis, and demanding clarity on the criteria for restoring operations.
Carriers grounded for days as a result of the ash cloud are becoming increasingly sceptical over the situation, particularly given that several positioning flights have revealed no evidence of technical threats.
UK cockpit union BALPA acknowledges the pressure on air navigation services to take precautionary action but it is irritated at the extent and duration of the airspace closure over this particular volcanic eruption.
BALPA is seeking clarification on whether the UK air navigation service NATS and the country's meteorological office have consulted with other authorities experienced in ash-cloud analysis.
"Pilots will want to know on what basis the decision to re-open is being taken," says BALPA general secretary Jim McAuslan, adding that the union needs to understand the specific criteria involved and whether the safety assessment is founded on computer models or flight-testing.
"We are willing to help analyse the current data, identify gaps and provide aviators' input."
McAuslan also says that the EU passenger compensation regulations covering flight delays were "never designed with this situation in mind". He insists that the Government and EU authorities must act to ease the short-term financial impact on carriers, some of which, he says, are "staring bankruptcy in the face".