ILS instrument accuracy? Help......

"Teacherjh" wrote in message ...

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

Three degrees I think. And remember the localizer is at the far end of the
runway (on the front course).

The glide slope transmitter is often separate.

It's always separate. The glide slope transmitter is down approximately
where the touchdown is (and obviously off to the side of the runway).

In article , Ron Natalie
wrote:
The glide slope transmitter is often separate.
It's always separate. The glide slope transmitter is down approximately
where the touchdown is (and obviously off to the side of the runway).

Not only is the G/S transmitter separate, the signal is bounced off the
ground from the transmitter toward the approach end of the runway. That
is why TERPS requires a specified distance of flat empty ground ahead
of the runway threshhold.

I had a similar problem with my HSI, my nav receiver went through the RNAV then to
the HSI, my avionics shop told me the rnav was bad, they removed it and problem
solved.


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? 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

In article , 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.

When was the last time the required VOR checks were performed?
This is an instrument requirement, isn't it?
Check your AFD for a VOT in your area.
If no VOT, perform and airborne check with two VOR receivers, if
installed.

On Sat, 20 Sep 2003 16:24:18 GMT, EDR wrote:

When was the last time the required VOR checks were performed?

That check does not verify the accuracy of the localizer and/or glide path
receivers in the unit.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

EDR wrote

When was the last time the required VOR checks were performed?
This is an instrument requirement, isn't it?
Check your AFD for a VOT in your area.
If no VOT, perform and airborne check with two VOR receivers, if
installed.

VOR checks have nothing to do with LOC accuracy. Two separate
receivers sharing the same tuning head and CDI.

Bob Moore

In article , Robert
Moore wrote:
VOR checks have nothing to do with LOC accuracy. Two separate
receivers sharing the same tuning head and CDI.

So what happens when both nav's are dialed in to the same localizer
frequency?
Do the indicators read the same?
Or is there a difference?
Which one yields a more accurate track?

On Sat, 20 Sep 2003 23:31:56 GMT, EDR wrote:

In article , Robert
Moore wrote:
VOR checks have nothing to do with LOC accuracy. Two separate
receivers sharing the same tuning head and CDI.

So what happens when both nav's are dialed in to the same localizer
frequency?
Do the indicators read the same?
Or is there a difference?
Which one yields a more accurate track?

If you are interested in doing a flight check of your LOC and GP receivers,
the procedure is outlined in AC91-16.

But to just check the accuracy of the LOC & GP receivers and indicators
systems, I would do a portion of the test which consists of flying directly
over the OM at the GP intercept altitude, and at approximately a 45° to the
LOC course. The GP needle should go from full up to full down deflection;
and the LOC & GP needles should be centered when passing over the OM.

This procedure does not check the LOC flag alarms or deviation sensitivity,
but if it's grossly abnormal, it is additional evidence that the unit
should be bench-checked.



Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Which approach was it, 24 or 06?
My last approaches at BHM seemed to be spot-on, except for pilot induced
variation of course. (about 3 mo ago for 6, 2 mo for 24 in heavy smoke).

Ben
N26RR
KBHM


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



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.518 / Virus Database: 316 - Release Date: 9/11/03