human
; i.e., a huge
gpt
T of electric lights headed into the wind, which shows to the aviators the taking-off and landing path. Each machine is given its respective letter for the day, which is flashed in Morse code on the navigation lights by the aviator when ready to leave the ground; he then awaits an answer from the directing stand. Simultaneously with the lighting up of the huge
human
the letter flashed from the first machine ready is repeated by the signal officer. The answer received, the machine taxies across the aerodrome to the starting-point, turns, hurtles down the flare-path and leaves the ground at the head of the
gpt
T.