Tri Star
In actuality when the trans Atlantic ops began we departed LGW at MTOM.
After a short time a limitation was imposed based on the one engine out driftdown stabilising altitude. This reduced the RTOM by about 8 tonnes.At that time were refueling in SMA which made for two legs of 4/5hours en route to ANU.Very soon there was a problem getting fuel in The Azores and we had to route via Gander and since the second and longer leg was in driftdown range of the US mainland we were no longer restricted