Eurocontrol's head of airport operations and environment, Paul Wilson, says he believes that for every ATM incident reported by a controller, probably more than 10 go unreported.
And Marc Baumgartner, president of the International Federation of Air Traffic Controllers' Associations (IFATCA), says the lack of a widespread corporate and legal "just culture" that encourages confidential reporting is holding back safety advances.
Baumgartner observes that car safety has advanced greatly over the past 20 years because there are so many serious accidents that the data becomes available without the need for reporting. But in aviation, he says, accidents are few, so incident data is the most reliable indicator of system and human faults that might one day cause an accident if they are not recognised and corrected.
Baumgartner suggests Eurocontrol is being denied full reporting because of employees' fear of reprisal.