There was no particular trouble with the F-BTSC. It was on a D-check. Two other Air France Concordes have also passed it: F-BVFA and F-BVFB
After 12,000 hours of flight, which means 4,000 landings and take-offs, the Concorde gets on D-check. The operation is lasting a year. During this year, 27 spezialized mechanicians invistigate the whole aircraft, : visual, radiographical or ultrasonical checks. The work totals 60,000 hours of checking, piece by piece. After three weeks of ground tests, two flight tests are performed. Of course, the liverery has been re-painted during the program.
The F-BTSC is the heaviest Concorde of all the Air France fleet: it is one ton heavier than the lighter (F-BTSD)ng the first to be delivered (6 January 1976) it is two years older than the 6th to be delivered - the SD, on. During this time some weight has been saved apparently.
Also the SC is a 100 and the others are 101.
Because it is heavier, and thus consuming more fuel, I assume that's why it is the less used of the fleet (on the opposite the SD performed most of the world tour flights). And that's why there's only so few photos of it...
BTW, the official name of the aircraft is "Concorde", not Concord. This word has the advantage of being common to English and French. However the British agreed to let the "e".