Originally Posted by
Old and Horrified
The reason was that there was not enough air coming out of an idling engine to keep the aircraft presurised, so on descent, we always had to keep number 2 at a medium thrust level (10,800 N1 or N2 maybe? - too long ago to remember).
The Spey was the same engine as in the One-Eleven, with only two engines. I wonder how they managed then ......