Germany’s second-largest airline, Air Berlin, was forced to cancel dozens of flights on Tuesday due to an unusually high number of pilots calling in sick, the company said.

Over 100 national and international flights were to be grounded, affecting schedules at major German airports including in Berlin, Dusseldorf and Munich, reports Efe news.

“Air Berlin is currently seeing an exceptional high number of sickness reports of their pilots. For this reason a number of flights will have to be cancelled today (Tuesday),” the company said in a statement on its website, advising those due to travel on an Air Berlin flight to call a customer service number before arriving at the airport.

Air Berlin filed for bankruptcy on August 15 after losing support of its former shareholder, nited Arab Emirates’ Etihad Airways.

Several corporations, including German flag carrier Lufthansa, are expected to submit bids for Air Berlin’s assets before a deadline slated for Friday.

Air Berlin continues to operate due to a 150 million euro ($180 milliom) credit loan from the German government.