Bart Neyens of the socialist union insists that the new security gates that were introduced last March are far from reliable: "We are aware of 50 incidents. Dozens of passengers passed through the gates without a ticket."
Last Sunday two passengers even managed to board a plane without a ticket!
Members of the socialist and liberal unions will work to rule on Monday: "Thorough checks on baggage are possible. Security staff may even stop passengers on the car parks to check their ID. We're not trying to harass the travelling public."
Liberal trades unionist Thierry Vuchelen says that problems started at the same time as the terror alert: "The federal police have taken a series of measures, which we support, but in the long term these measures endanger the jobs of our people."
Bart Neyens warns that the problems with the security gates are the tip of the iceberg: "There are numerous entrances that allow you to get to an airplane without a ticket and without a security screening."
Inspectors who wish to intervene are stopped: "When somebody needs to be stopped, he or she is often not found. The entire terminal is supposed to be evacuated and other airports alerted but this never happens."
"Commercial interests conflict with safety interests. That's why the authorities should take the lead on security issues. The aviation directorate-general is supposed to receive reports on incidents, but that simply doesn't happen."
Some 100 security staff are employed at Brussels Airport. They want the government to clarify what will happen to them in the future.