Mailing List lml@lancaironline.net Message #60513
From: Tim Olson <Tim@myrv10.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Dumb Chelton Question --
Date: Mon, 19 Dec 2011 16:37:09 -0500
To: <lml@lancaironline.net>
John,

Not a dumb question.  I think it includes the total hold
and the rest of the approach.  Once you're on the final
leg, it will show the distance to the runway, too.  But
DEST is to give you an idea of how many actual miles you
need to go to get to the DEST....and that includes maneuvering.
What I can't tell you exactly is how many miles long that hold
is.  Judging by the 2.5 mile ring, and with a piece of string,
it seems to be about 6 or 7 times the distance of the radius
of the 2.5mi circle.  If that's true, then you'd have 15 to
17.5 miles of hold to fly, plus, you're not quite to EYWOK
yet, so there's another .8 miles there.  Add that to your
11.1 miles or so and you're probably right in the ballpark
for the 27.6 that's displayed.  At any rate, it's the
entire distance to fly for the approach.

** Note the "SUSPEND" lit up on the blue annunciator, too.
It's telling you that it WILL fly the hold, unless you
hit the CONT soft key.

I find that when I fly long approaches, especially with DME
arcs or with IAF's that are way out perpendicular to the
approach, you can find yourself being <10 miles from the
airport but still needing 45 miles to get there. I remember
once I seemed almost home free and I still had 80 real
miles to go. So it is deceiving.

The RNG, to answer another persons question, is the range
in fuel and time...so in the .jpg he's got 1029NM or
6:33 minutes of range left.  That number fluctuates
with airspeed and fuel flow.

Fun stuff though.
Tim

On 12/19/2011 9:00 AM, John Hafen wrote:
OK Gents:

Pull out your iPads and look at the RNAV (GPS) RWY 16R approach to KPAE.

 From the IAF of EYWOK to the end of the runway is 11.1 miles.  So, according to my limited understanding, it would seem that your distance to KPAE would be 11.1 miles plus how far you are from EYWOK.

On the screen shot below, I'm just outside of EYWOK -- 0.8 miles according to the information in the lower right of the screen.

One would think that the distance to KPAE would be 0.8 plus 11.1, or 11.9 miles rather than the 27.6NM listed below.

Here is a screen shot that makes sense.  The distance to EYWOK is 0.7NM, and the distance to KPAE is 11.8, which makes sense, knowing that EYWOK is 11.1 miles from KPAE.


In this shot, I'm abeam ETWOK, so one would think that the distance to KPAE would be close to 11.1 miles, yet it says I'm 42.2NM away.


I know that I'm going to be really really embarrassed when you guys explain to me what I'm doing wrong and or how I'm hitting the wrong buttons or don't know how to read my own navigation screen.

But my curiosity is killing me.  So I'll swallow my ego for the moment and open myself up to ridicule and criticism (I'll just assume you guys are my first X-wife) just to find out what I'm doing wrong.


 From my perspective, I'm close to EYWOK, 11.1 miles from KPAE.  And I get three readings about my distance from KPAE:  27.6NM, 11.8NM, and 42.2.

Your help and 'explanations are much appreciated!

Cheers,

John Hafen

N413AJ IVP4 350 hours

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