Originally Posted by
Helen49
'YD' was the flashing green identification beacon [common on civil aerodromes in the past] and WFU probably in the late 60s.
We could see the YD beacon from our back window mentioned upthread; t lasted well into the seventies and possibly up to the runway extension.
Morse light beacons were common on aerodromes well after the sixties. LHR had something on the SW extremity as late as 78.