European ombudsman Nikiforos Diamondouros today criticised the European Commission (EC) for providing "misleading information" to air passengers during last year's volcanic ash crisis.
The ombudsman has given the EC until the end of May to describe the measures it has taken to avoid the same thing happening again in the future.
Diamondouros says the EC provided passengers with inaccurate information concerning compensation for delayed luggage.
Following an earlier prompt from the European Regions Airline Association, the ombudsman has ruled that a Q&A document published by the EC on websites offering information for passengers stranded during the ash cloud crisis - which led to the closure of European airspace for a week in April - "wrongly implied that passengers had an automatic right to compensation in all cases involving delayed luggage".
The ombudsman adds that it took the EC "two weeks to conclude that part of the Q&A document was indeed misleading and more than a month to remove it from the websites".
This is the second time the ombudsman has accused the EC of publishing misleading air passenger information. If the information provided by the EC by the end of May is insufficient, it faces a possible investigation into systemic problems.
European transport commissioner Siim Kallas announced earlier this month that Europe's controversial passenger rights rules are to be modified, although it remains unclear whether the planned review will take a tougher or more lenient view of the current regulations.