View Full Version : CDA question

9th Dec 2006, 13:37
Hello folks,

trying to find any threads about CDA? saw it on forums in past, but cannot find now. anyone could help?

9th Dec 2006, 13:46
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.

9th Dec 2006, 15:26
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.""

9th Dec 2006, 16:42
thanks for the link