Analysis of advanced flight management systems (FMSs) optimized profile descent (OPD)

This paper presents the events based on different scenario (with no wind) in scenario 1 all systems met all attitude constraints, also all but one system met the 280 nots speed constraint within 10 knots. In scenario 2 (un-forecasted wind not entered into the FMS) several systems wer not able to comply with the altitude restriction at PLDGE. The full VNAV systems met the speeds within 10 knots, while the advisory systems met the speed within 5 knots on the descent path. Advisory systems tended to fly paths that connected either the tops or the bottoms of the altitude windows, while the full VNAV systems would often transit at various levels within window. Full auto VNAV systems tended to delay the TOD from where the constrained path would have started - consequently they remained above the constrained path until late in the descent 2. Advisory VNAV systems also tended to delay the TOD and stay high. In scenario 3 it is demonstrated that the aircraft, when unconstrained and allowed to descend based upon the aircraft performance parameters: descended at a steeper.