fizz57
... Barbados route...half-way between the Azores and Barbados...a thousand miles from anywhere with limited diversion options and marginal fuel in case of engine failure and subsonic cruise...what sort of contingency plans were in place?...
As well as carrying sufficient fuel to arrive at BGI with standard fuel reserves remaining, there was also a requirement that sufficient fuel be carried to ensure that, following an engine shut-down
at any stage in the flight, Concorde could divert, on three engines, to a suitable diversion airfield, and still arrive there with standard fuel reserves remaining.
It was this requirement - the three-engined diversion requirement - that often required more fuel to be loaded - above the basic LHR-BGI flight plan fuel figure - often bringing the total fuel required up to or over the full tanks figure and so became the limiting factor on this route.
Perhaps the main difference between Concorde and most subsonic aircraft, following an engine shutdown in cruise, was that Concorde would suffer a much greater loss in range. From four-engined supersonic flight to optimum three-engined subsonic cruise the loss in range would have been in the order of 30-35%.
This was mainly because Concorde, following an engine shut-down in cruise, would have to decelerate and descend, and thus 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 much less efficient regime, at M0.95, at around 30,000ft, in a higher drag subsonic cruise 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 wind components at subsonic cruise levels to these airfields, were all taken into account at the flight planning stage, with the forecast subsonic cruise wind component to Antigua generally being the most critical factor.
If the weather conditions at and en-route to these diversion airfields were favourable, flight planning was straightforward. If the weather conditions were unfavourable, flight planning got more difficult, but the necessary fuel was always carried, passenger numbers limited or a re-fuelling stop planned.
...While I'm sure you had all the angles covered, was it really a nail-biting moment...
No, not really.
LHR-BGI was certainly the most demanding route on Concorde, and required careful planning, good tactical awareness and diligent in-flight monitoring, however the flight planning procedures and tactical decision making processes were standard and would have been very familiar to any ETOPS rated pilot.
With one exception.
Concorde would still have got you to a diversion airfield following a second engine failure!
Best Regards
Bellerophon