[jhb_airlines] Re: Radio Nav

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Tue, 21 Dec 2004 21:56:29 -0000

I'd like to suggest a slightly different procedure here. Because you =
have
two options for directional control it's best to make full use of both. =
HDG
mode is more flexible in that you can easily alter your heading as you =
fly
but if CRS/NAV mode is selected and you are tracking a radial then you =
can't
touch NAV1 at all (except the standby frequency).

Let's use you original EGPD SAB NEW route for this example.

On departure tune NAV1 into the first en route beacon (SAB, not ADN) and =
set
up the correct radial (about 185 at a guess) in the CRS/NAV box. You =
should
be able to get this value from FSNav or your flight plan - and you =
should
keep this figure in your head. Set the standby frequency to the second =
point
en route (NEW). At the same time set the HDG value to runway heading.

On take off engage AP in HDG and ALT modes so the aircraft initially =
flies
runway heading and begins a climb to the first assigned level. Stay on
runway heading until you have got gear up and cleaned up the flaps - =
it's
not unusual to fly out to around 4nm before turning on track. The =
exception
here is when flying a SID but any SID's that require turns within 4nm =
should
be left alone until you get more familiar with the aircraft and your
reactions are faster. If you are happy to start turning before you have
completed the flap sequence then alter the HDG value to match the track =
you
memorised - 185 in this case. This will put you roughly on course to SAB
whilst leaving you free to complete the after take off checks.

Once the aircraft is tidy you can now concentrate on your navigation. =
The
autopilot will be pointing you in the right direction now (in HDG mode) =
but
a glance at the HSI may show you that you are slightly left or right of =
the
185 radial between ADN and SAB. Alter course on the HDG bug to fly an
intercept for the right track and once you are on a closing heading for =
the
radial switch the A/P from HDG to NAV mode and let it capture and fly =
the
radial.

The point I must make here is that routes along airways and for =
instrument
approach procedures are not rigid - they are guidelines for flying. You
don't have to get neurotic and fly the exact path shown on the plates
because then you would be spending too much time navigating rather than =
on
aircraft handling. An aircraft flying from Aberdeen to SAB would never =
take
off and turn back to the ADN beacon before setting course for SAB - he =
would
just turn direct to SAB and gradually intercept the ADN - SAB radial. =
Same
with turning from one VOR to another - you don't fly directly over the
beacon very often. As one Trident pilot remarked on flying the dogleg =
route
from Jersey to SAM to MID - "If we flew north until we hit SAM and then
turned right to MID we would end up 8nm north of the airway."

As you track towards SAB take a look at your actual heading as this will
give you a rough idea of any drift. Set this value in the HDG window as =
you
will need it. Approaching to within 10nm of SAB VOR switch over to HDG =
mode
to free up the NAV selector. Switch NAV1 over to NEW frequency (flip the
frequencies if you use a radio with a standby option) and dial up the =
new
(sic) course in the CRS/NAV selector (166). At the same time dial up the
next en route point frequency in the standby frequency box.

You are now flying on HDG mode and your display will no longer be =
showing
you the radial to SAB because you have reset it to NEW. It doesn't =
matter
that you have lost course guidance because you are hardly likely to =
diverge
much from your original track in the few miles to run to the VOR. If you =
set
the HDG value to the heading shown on the HSI at the time you =
disconnected
the NAV mode you will still pass within half a mile of the beacon. =
However
this is immaterial because now you are looking at the HSI to lock on to =
the
next radial to NEW.

It is most likely that the needle will start off at full deflection but =
as
you get near to the beacon it will come alive and start moving towards =
the
centre. As soon as you see the needle moving you can re-engage NAV/CRS =
mode
and let the autopilot capture the new radial. And so it goes on...

If the explanation above baffles you then what I could do is set up an =
MP
session (or FPI) and talk you through it.

bones

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of frank fisher
Sent: 21 December 2004 19:41
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Radio Nav


John
Perhaps I am wording it wrong.
I set Nav1 stnby to the first beacon, rotate dial to get heading, take =
off,
and switch it Nav1 active, with AP on and HDG, the AC turns to and flies =
to
the beacon, to/from is facing up. I then set the Nav1 Stby to the next
beacon ready, at the time, switch it to active and tune the Stby to the =
3rd
beacon. The to/from flag is now down, and what ever I do, the AC will =
try to
backtrack. I get the impression I am still locked on the first beacon, =
and
cannot change it. Last night, in desparation, I tried for the very first
time, to use the ADF, after realizing that the two sets of numbers at =
the
airfield in FSNav, refer to a) the Nav Frq B) the ADF Frg.(this after =
nearly
10 years of playing around with FS, I said I was a dumbo). This was =
between
EGNC and EGNT. I have tried setting the same Frg in both the Nav1 and 2
active and Stby, no joy. To recap, left EGGP for WAL, got to Wal then =
tried
to get to WL then EGNC, finally got to EGNC, after a lot of choice =
words,
then discovered ADF which got me to EGNT. Anyway, will not bother you =
any
more this year, as we all will be busy, perhaps we can hook up via TS or
messenger in the new year, and talk it through, Email is fine, but too =
slow
and clumsy. Frank F







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