During the descent into Edinburgh, smoke began to fill the flight deck. The No. 2 engine was identified as defective and was shut down. The aircraft landed safely and was then ferried to a maintenance base where the defective engine was changed but, on the first flight thereafter, smoke again filled the flight deck. It was concluded that, on the first occasion, a bearing failure lead to seal damage and contamination of the air conditioning system. It appeared that residual oil in the system, resulting from the initial failure, had not been eliminated during the rectification and was responsible for the second event. This AAIB Bulletin reports on both events. AAIB file EW/G2006/09/22 relates to the event which took place on 20 September 2006, and AAIB file EW/G2006/09/26 refers to the second event which occurred on 26 September 2006.