ILS instrument accuracy? Help......

I'm just starting to work on my Instrument Rating and yesterday when doing an
ILS approach I was keeping the localizer centered and my instructor told me to
look up about a mile out. We were maybe 200 yards off the centerline. Next
one we stayed on the centerline (visually) and the needle was 1/2 deflection.

Any thoughts about what to do? It seemed like a practice ILS I did at another
airport didn't do this a couple of weeks ago. Could it be this one facility
(BHM)? Do I need an avionics shop to look at it?

I'm new at this so I'm not really sure what step to take next. Any help will
be appreciated.


Trip

(TripFarmer) wrote:
I'm just starting to work on my Instrument Rating and yesterday when doing an
ILS approach I was keeping the localizer centered and my instructor told me
to
look up about a mile out. We were maybe 200 yards off the centerline. Next
one we stayed on the centerline (visually) and the needle was 1/2 deflection.


Any thoughts about what to do?

Get your radios checked?

"TripFarmer" wrote in message
...
| I'm just starting to work on my Instrument Rating and yesterday when doing
an
| ILS approach I was keeping the localizer centered and my instructor told
me to
| look up about a mile out. We were maybe 200 yards off the centerline.
Next
| one we stayed on the centerline (visually) and the needle was 1/2
deflection.
|
| Any thoughts about what to do? It seemed like a practice ILS I did at
another
| airport didn't do this a couple of weeks ago. Could it be this one
facility
| (BHM)? Do I need an avionics shop to look at it?
|

Could be your radios. Or if you have a GPS tied to your CDI you might have
inadvertently selected "GPS" instead of "NAV" and so the CDI needle was
actually indicating your position to some GPS course instead of the
localizer. I am seeing this error a *lot* in training.

In article ,
C J Campbell wrote:

Could be your radios. Or if you have a GPS tied to your CDI you might have
inadvertently selected "GPS" instead of "NAV" and so the CDI needle was
actually indicating your position to some GPS course instead of the
localizer. I am seeing this error a *lot* in training.

What ACUs will allow you to select GPS display when a LOC frequency is
tuned in on the NAV? I know UPSAT's won't actually select the GPS until
you tune a normal VOR on the associated NAV.

--
Ben Jackson

http://www.ben.com/

Ben Jackson wrote:
In article ,
C J Campbell wrote:

Could be your radios. Or if you have a GPS tied to your CDI you might have
inadvertently selected "GPS" instead of "NAV" and so the CDI needle was
actually indicating your position to some GPS course instead of the
localizer. I am seeing this error a *lot* in training.


What ACUs will allow you to select GPS display when a LOC frequency is
tuned in on the NAV? I know UPSAT's won't actually select the GPS until
you tune a normal VOR on the associated NAV.

I've seen UPS installs where that's true, and where that's not true. Apparently
it depends on how it's installed.

Remove SHIRT to reply directly.

Dave

"Ben Jackson" wrote in message
news:PeIab.524381$uu5.87404@sccrnsc04...
| In article ,
| C J Campbell wrote:
|
| Could be your radios. Or if you have a GPS tied to your CDI you might
have
| inadvertently selected "GPS" instead of "NAV" and so the CDI needle was
| actually indicating your position to some GPS course instead of the
| localizer. I am seeing this error a *lot* in training.
|
| What ACUs will allow you to select GPS display when a LOC frequency is
| tuned in on the NAV? I know UPSAT's won't actually select the GPS until
| you tune a normal VOR on the associated NAV.
|

The KLN-94 installation in all the new Cessnas has a NAV/GPS button which
must be pushed manually. The NAV/COM is a separate unit; you can tune in all
the localizers and VORs you want, but they will not be displayed on the CDI
unless you select NAV on the ACU.

(Ben Jackson) wrote in
news:PeIab.524381$uu5.87404@sccrnsc04:

What ACUs will allow you to select GPS display when a LOC
frequency is tuned in on the NAV? I know UPSAT's won't
actually select the GPS until you tune a normal VOR on the
associated NAV.


With the installations we have, the HSI has no idea what's
selected, or what frequency. There's a push/push button, which
cycles between VOR & GPS, and the HSI just gets voltage from
whichever is selected. There is no logic at all to prevent
using either one. The nav radios and the GPS are completely
independent, and have no relation to each other in any way.

--
Regards,

Stan

The 'preferred' option is to have a loc frequency automatically force the
NAV/GPS switch to go to nav mode.


Almost all wiring suggestions imply that as the deafult mode.

So you barrel along with your gps upto the IAF cros tracking your favourite
VOR then swap frequencies
on nav1 and bingo your automatically lined for a loc intercept.

Personally I find it it irrating and also if P2 happens to tune the ILS/DME
for cross references
purposes and the A/P is on then you can do a beautiful intercept of the ILS
for an airfield you just
happen to be passing!!


Peter


"Stan Gosnell" wrote in message
...
(Ben Jackson) wrote in
news:PeIab.524381$uu5.87404@sccrnsc04:

What ACUs will allow you to select GPS display when a LOC
frequency is tuned in on the NAV? I know UPSAT's won't
actually select the GPS until you tune a normal VOR on the
associated NAV.


With the installations we have, the HSI has no idea what's
selected, or what frequency. There's a push/push button, which
cycles between VOR & GPS, and the HSI just gets voltage from
whichever is selected. There is no logic at all to prevent
using either one. The nav radios and the GPS are completely
independent, and have no relation to each other in any way.

--
Regards,

Stan

"Peter Bondar" wrote in
:

The 'preferred' option is to have a loc frequency
automatically force the NAV/GPS switch to go to nav mode.

Well, maybe preferred by some, but I may want to tune in the
localizer while I'm a long way out, getting ready for the
approach, but navigating on GPS until I'm inbound, or at least
on vectors. Forcing VOR mode just because a localizer is tuned
is simply a stupid way to do things.

--
Regards,

Stan

We were maybe 200 yards off the centerline. Next
one we stayed on the centerline (visually) and the needle was 1/2 deflection.


Perhaps the ILS transmitter is not on centerline? They can be offset, but I
don't know by how much.

The glide slope transmitter is often separate.

Jose

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