The venerable 146 doesn't like idle descents from top of drop. Lots of dings as air valves don't stay open and aircon packs drop off line, added to internal seals requiring some airflow to work properly.
BAe advise a descent schedule of 70% N2 above FL250, 65% N2 above FL250 and Flight Idle up to FL200.
My employer has a SOP of 70% N2 to FL150.
BUT then one must factor in icing conditions if present, in which case a power scheduel of 72%N2
plus 2% N2/5000' AMSL must be maintained to keep the ant-ice/de-ice going.
Then you couple this with an autopilot that in IAS hold can give a ROD of between 1000 FPM and > 4000 FPM.
A colleague has perhaps the best system, FL >250, TOD 70nm, FL< 250, TOD 60 nm.
