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Old May 2nd 08, 03:35 PM posted to rec.aviation.ifr
Airbus[_4_]
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Default Flying Mag Clueless about LPV and NACO

In article , says...


Airbus wrote:
In article ,
says...


John T wrote:



Oh, I did write them about it.

They erected a giant stone wall.




Maclellan says some readers took him to task for claiming that an LPV was flown
exactly like an ILS. He and Collins surmised that some of the confusion could
be attributed to charting ambiguities on NACO charts. This indeed seems to be a
pet peeve of theirs, as Collins goes into it in one of the Sporty's videos as
well, and uses the same DMW approach as an example, if I recall.

The gripe seems to be that the profile view in the NACO chart does not show a
stepdown, as the Jepp does, neatly intercepting the glideslope from below. In
purely graphical terms, they have a point. An architect would agree it's
misleading, and the continuous, sloping line on the NACO chart suggests a fixed
descent rate from the IF would have you magically intercept the glideslope at
the right place and altitude and even on the correct slope, which of course is
not true, and is not the way it's flown.

You argue this is a conventional depiction, unchanged from the way they have
always depicted ILS's and simply knowing the convention allows the pilot to fly
it correctly and intercept at the right altitude at the lightning bolt. You
certainly have a point as well, but if it were that clear and simple perhaps
there would have been fewer confused readers writing to Mac because they didn't
understand how to fly the approach.

We don't know what those readers wrote, but perhaps he has some reason to
believe their confusion stems in part from an imperfect charting convention,
which could stand some clarification.