Typically a jet descend into the TMA is 270-300kts (indicated) ish which is above best glide speed. During descent, if asked to slow down, it means being to asked to slow towards best glide speed which means angle and therefore rate of descent will decrease. Also (for those of you who remember trig) for a given angle of descent, at a lower forward speed we will have a lesser rate of descent. eg. 3 deg angle of descent: 250kts groundspeed rod=1327fpm but at 400kts groundspeed for the same angle rod=2123 fpm. Also, if required, the speed brake is most effective at increasing angle of descent at high speed but is apparently not the preferred method to get down for pax comfort reasons.
sr
Last edited by speedrestriction; 25th Aug 2010 at 16:47.