BobAgg
...tell me if the flight engineers were also able to pilot the aircraft?...
No, BA flight engineers were never trained to pilot Concorde.
On all the various BA fleets that required a flight engineer, he was always a professional engineer, and not a pilot. He was required to hold a CAA Flight Engineer’s Licence, and was on a different seniority list to the pilots.
They were not, as was the practice in several airlines in the USA, newly hired pilots awaiting their turn to upgrade to the F/O seat.
Many experienced flight engineers came to BA on retirement from the military, others were ground engineers within BA who successfully applied for vacancies that were advertised within the company, and were then trained by BA.
In the Concorde simulator, during a training session, very occasionally there might be a pilot incapacitation scenario that required the F/E to sit in a pilot’s seat and assist the remaining pilot, or attempt an autoland on his own. Likewise, following a simulated F/E incapacitation, the F/O would move to and operate the F/E’s panel, but that was as far as it went.
That is not to say that some of the F/E’s would not have made a pretty good job if called upon to do so in a dire emergency. Several of them had PPLs, with a few CPLs and instructors ratings about as well; however it would have depended very much on the luck of the roster as to who you had on the day.
Many BA flight engineers subsequently retrained as pilots, and several are still flying with BA today. Most subsequently upgraded to Captain, and few now hold appointments as instructors.
One or two of them even post on PPRuNe!
Best regards
Bellerophon