turboP
9th Dec 2006, 12:37
Hello folks,
trying to find any threads about CDA? saw it on forums in past, but cannot find now. anyone could help?
vapilot2004
9th Dec 2006, 12:46
One thread found here. (http://www.pprune.org/forums/showthread.php?t=139176&highlight=Continuous+Descent+Arrival)
Try searching for 'continuous descent arrival' for more.
rigpiggy
9th Dec 2006, 14:26
Flew several NPA's yesterday, we use the Jepps which have a Constant Descent Angle, had the F/O fly it to show him the decreased workload that went with it. We also have one A/P that has a hill on 3 mile final that if you fly the step down you will get a GPWS terrain alert, disconcerting to say the least. Another thing is to bug the track off the irs/gnss on approach, if you have to go outside the bug you are overcorrecting or have to rebug.
quoted from the other thread
A CDA on final approach has been promoted to reduce CFIT on NPAs; this avoids step downs during the procedure, and normally mandates a GA at MDA if nothing seen. A difficulty for the industry is to train crews to adapt from a decelerating approach on an ILS (where the vertical path is constrained), to an open vertical path (unconstrained) on NPAs. Recent CFIT accidents and incidents recorded crews flying VOR/HDG and VS during a decelerating NPA; they forgot the basic flight mechanics that a deceleration at constant VS will increase the flight path angle and aim the aircraft short of the runway; thus during a CDA on a NPA, the VS must be reduced as speed is reduced. To combat these problems some operators now fly constant speed / configuration NPAs. Flight crews should carefully brief NPAs, use the tables of range vs distance now on the charts, and treat all NPAs as something very different and potentially hazardous.""