As soon as the ground crew commenced preparing the aircraft they would be able to estimate what the night's operation was likely to be based on the payload of bombs (or sea mines) coupled with the fuel load to be pumped into the wing tanks [REF].
Signalled in the darkness by an arrangement similar to traffic lights,[REF] the crew awaited their turn to take off, wireless traffic was kept to an absolute minimum to avoid alerting the German wireless listening services [REF].