Originally Posted by
Check Airman
Bit of circular logic, but I’ll answer your question. They came about when 707s, A300s and DC8s were flying around.
Most anything flying around today (and especially LHR) is very quiet.
Tens of billions have been spent since the ‘60s on developing, certifying and fielding quiet aircraft, but we’re still saddled with procedures developed from “water wagon” 707s. Landing aircraft noise footprint may not be engines but flap and wing noise. An A220 taxis by and you hear the APU over the engines.