Doug Carter wrote:
wrote:
Part of the problem, I suspect, is modern FMS/LNAV aircraft trying to fly a
ancient round-dial aircraft departure procedure, especially one that
includes an NDB crossing and an NDB bearing crossing.
I would think the FMS has the DP in its database. It sounded like the
problem was blowing altitude, not route.
True. But, each FMS vendor has their own idea of how to code a non-RNAV DP,
which has resulted in some pretty serious problems from time to time. It almost
caused CFIT with a "round dial" DP at Reno being misapplied by crews using
FMS/LNAV.
With RNAV DPs the vendors are pretty well forced to code it correctly. Even
then, some boxes will lead a fly-by WP differently than others.
As to TEB, some crews perhaps busted an altitude because it appears they have
passed the restricting fix when, in fact, they have not. Based on similar
situations at other locations, it is certainly one possibility for an apparent
pattern.
If this were just one or two flights, we wouldn't be hearing about it.