newswatcher
As you seem to suspect, it is complete rubbish.
As well as loading sufficient fuel to arrive at BGI with standard fuel reserves, enough fuel must also be loaded to meet the tactical requirement that, following an engine shut-down at any stage in the flight, Concorde can still divert, on three engines, to a suitable diversion airfield, and arrive there with standard fuel reserves still remaining.
The main difference between Concorde and other subsonic aircraft in a similar situation is that Concorde will suffer a much more substantial loss in range. From four-engined supersonic flight to optimum three-engined cruise there will be a loss in range in the order of 30-35%.
This is mainly because Concorde must now leave a very efficient flight regime, at M2.0 and 55,000-60,000ft, with relatively low drag, low winds and very cold outside air temperatures, for a higher drag subsonic regime at M0.95, at around 30,000ft, with warmer outside air temperatures and much stronger, probably adverse, winds.
The forecast weather at the principal en-route diversion airfields of Santa Maria, Lajes, Bermuda and Antigua, along with the calculated subsonic wind components to these airfields, are all taken into account at the flight planning stage.
If the weather conditions at and en-route to these diversion airfields are favourable, flight planning is straightforward, if the weather conditions adverse, flight planning gets somewhat more difficult, but the necessary fuel will always be carried, or a re-fuelling stop planned.
On Concorde, the LHR-BGI route is the most demanding and it does requires careful planning and good tactical awareness, but the flight planning procedures are standard, and any twin-jet ETOPS rated pilots would find that they were very familiar with all the planning processes and tactical decision making involved.
With one exception.
Concorde will be able to get you to a diversion airfield after a second engine failure!
Regards
Bellerophon