paulc.......You're right in saying there were 10 production Mercures (regs F-BTTA-BTTJ), however the prototype F-BTMD was brought up to production standards sometime in the early 80's & put into service with Air Inter.. I worked on them as cabin crew in the late 80s/early 90s & remember them well esp. doing AF CDG-LGW flights on them for a couple of years round about 90-91. They were well liked by cabin & flight crew alike.