The powerplant configuration selected for Concorde, and its development to a certificated design, can be seen in light of the above symposium topics (which highlighted airfield noise, boundary layer management and interactions between adjacent engines) and the requirement that the powerplant, at Mach 2, tolerate combinations of pushovers, sideslips, pull-ups and throttle slamming without surging.[89] Extensive development testing with design changes and changes to intake and engine control laws would address most of the issues except airfield noise and the interaction between adjacent powerplants at speeds above Mach 1.6 which meant Concorde "had to be certified aerodynamically as a twin-engined aircraft above Mach 1.6".[90]