all unmistakeable
The RR Dart of course - 10 years with BMA lol
!-11 RR Spey start up
JT8's on 737-200, 727 or a DC-9 screaming down the taxy ways
JT3B on a 707 spooling up on APP
RB211 Tristar start up rumble
In more recent times -
RR RB211 535E4's on a 757
A320/321 NEO's CFM LEAP (and 737 MAX too)
Tridents/Comets/ RR Conway 707's and VC-10's were all just noise, crackle and pain lol