Hello everyone, I’m sort of new to this forum, so do forgive any oversight(s) on my part regarding this topic.
I have searched for any related topics, but was unable to find any. I do apologise if this issue has previously been raised.
Now let me start with the “issue”.
So basically I’ve been flying the MD11 and DC10s for quite a while, and notice that they have rather interesting descent physics. When I retard the thrust levers to idle on most aircraft (787, 777, A320, CRJ etc.), they tend to start off with a initial vertical speed of around -2600fpm from FL350 if I maintain 250KIAS, and this drops to around -1800fpm when I reach 10000ft MSL. (I understand that this is the “ideal” descent flight path)
For the MD11s and DC10s, they too will start off at around -2600fpm, but once I’m down to around FL230, I start to notice that the vertical speed has to drop to absurdly low levels in order to maintain 250KIAS (800fpm or even less).
I did do some research on this matter, but could not find anything on the matter. Could someone please enlighten me? Or is it just perhaps an isolated case? I thought that it was a result of the “28%N1” instead of the usual “20%N1” when at idle, but I’m really not sure.