From the report:
During the replacement of the MSV, the rogue O-Ring found blocking the orifice in the restrictor valve of the accident aircraft could, hidden in a union, have unknowingly been transferred from one side of the MSV to the other side by maintenance personnel
From SAS 5 days earlier:
"Confidence in the Q400 has diminished considerably and our customers are becoming increasingly doubtful about flying in this type of aircraft. Accordingly, with the Board of Directors' approval, I have decided to immediately remove Dash 8 Q400 aircraft from service," says Mats Jansson, President and Chief Executive Officer of SAS.
"The Dash 8 Q400 has given rise to repeated quality-related problems and we can now conclude that the aircraft does not match our passengers' requirements concerning punctuality and regularity. SAS's flight operations have always enjoyed an excellent reputation and there is a risk that use of the Dash 8 Q400 could eventually damage the SAS brand," says John Dueholm, Deputy CEO of SAS.
Maybe too early?