Originally Posted by
dixi188
Most BAC1-11s had a Plessy CSDS (Constant Speed Drive Starter) that made that distinctive sound. A few had a different starter that was much quieter, American Airlines I think.
I don't know what the Tridet had.
The three 1-11-400s, G-BBME, F and G based at BHX back in the 1970s - 1990s were all ex American Airlines -401s, and so far as I can remember made the trademark whine on start up. I recall the APU on the Trident was almost a loud as the Spey engines!