An Air Berlin Airbus A320-200, registration D-ABZN performing flight AB-7520 from Munich (Germany) to Palma Mallorca,SP (Spain), was descending towards Palma Mallorca, when cabin crew noticed the odour of old socks in the aft and forward cabin. The aircraft continued for a safe landing on Mallorca’s runway 24R.
Following landing cabin and flight crew went to see a doctor for medical checks.
Maintenance found the APU oil system had been overfilled causing oil to enter the compressor. The APU was cleaned. Both engines were found dry and clean. The occurrence aircraft returned to service about 6 hours after landing and departed for the return flight AB-7521 reaching Munich with a delay of 5 hours.
Spain’s CIAIAC did not respond so far to an inquiry sent by The Aviation Herald on Nov 9th 2016.
Germany’s BFU reported on Nov 10th 2016, that they had not received any information on the occurrence.
Full report here