I believe that the silica gel practice came about as a result of VTTS failing to prevent corrosion on turbine discs by proper storage. RR's first reaction to the degree of corrosion was to scrap them. I think they did get around to some form of recovery eventually. While I wasn't involved, I believe RR was not too happy about the competence of VTTS which may have coloured their view of the change from Marshalls. I believe the CAA would have also had to approve the change to Cranfield; did they have any issues?
EAP