Originally Posted by
Gonzo
What also might be a factor is that the end point of the DET SID is relatively a long way from LHR, so modern FMSs will moderate the climb rate. If the end point of the SID was brought closer to the airport (truncations, which have already occurred with WOBUN/BUZAD changing to UMLAT/ULTIB and SAM changing to GOGSI/GASGU) then this might result in steeper climb gradients.
Yes, although the GOGSI/GASGU height restrictions haven't changed from the old SAM SID, the ULTIB SID in particular has the "5000 ft or above" restriction at 13 nm along track, whereas the same restriction on BUZAD was at 18 nm.