used2flyboeing
...I recall a BA flight instructor told me that the flight engineer or FO flew throttles w/autothrottle unavailable b/c it was Sooo speed unstable .. "a real hand full" ..
I am very surprised you say a BA instructor told you this, but it is still rubbish.
Concorde was not ...a real hand full... nor was she ...Sooo speed unstable... that she required ...an extra human on the COncorde flight deck to work the throttles....
Concorde was speed unstable on approach, and a manual throttle approach was not as easy as on, say, a B747. However, manual throttle approaches, on four, three or two engines (both on the same wing) were all manoeuvres that were part of the initial conversion course and many recurrent checks thereafter.
Once trained for, such approaches were well within the capabilities of the average line pilot, and I can’t imagine why anyone would claim otherwise.
Regards
Bellerophon