Originally Posted by
chevvron
Back in the late '60s and early '70s, all BEA Tridents transmitted a 'beep' at the end of a transmission.
I had heard of that but by the time I became a "listener" it no longer featured. Didn't the BEA/BA 1-11-510s have an avionics fit that had some commonality with the Trident but was non-standard when compared to 1-11s generally?