An Austrian Airlines Airbus A319-100, registration OE-LDB performing flight OS-378 from Amsterdam (Netherlands) to Vienna (Austria) with 145 passengers, was enroute at FL350 about 50nm northwest of Erfurt (Germany) when the crew initiated an emergency descent due to the loss of cabin pressure. The aircraft diverted to Erfut for a safe landing on runway 28 about 26 minutes after leaving FL350. A replacement A319-100, registration OE-LDE was dispatched to Erfurt, resumed the flight and is estimated to reach Vienna with a delay of 9.5 hours. According to information The Aviation Herald received the loss of cabin pressure was caused by problems with the engine bleed air system. The airline confirmed a problem with the bleed air system, the crew therefore initiated a descent to avoid a loss of cabin pressure. It is still being investigated whether there was a defect with the bleed air system or an indication malfunction.