KX-155 Self Test?

[bob865]

I've finally started my instrument training and last night we went to fly an ILS for the first time.  I lined up on the localizer and..........no glideslope.  The needle never moved off center.  The localizer needle works fine.  I had been tracking it all afternoon.  Anyone know a simple way to test and see if it is the reciever or the indicator?  I'm thinking about the self test that the garmin GPS have where they command the needles to half deflection on startup so you can see the indicator and the interface works.  Does the KX-155 have anything similar?

[Jerry 5TJ]

14 minutes ago, bob865 said:

.....I'm thinking about the self test that the garmin GPS have where they command the needles to half deflection on startup so you can see the indicator and the interface works.  Does the KX-155 have anything similar?

No. 

[Jerry 5TJ]

A simple ramp test will tell if your KX155 is working.  The tech will bring an RF signal generator to the plane and apply a signal at the ILS frequency (around 330 MHz).  AM modulation at 90 Hz will cause full scale GS needle diflection.  150 Hz will drive the GS the other direction.   

[neilpilot]

First try to confirm that the GS isn't out of service.  Check the NOTAMS, ask another pilot to confirm operation or call the airport manager.  At my base the ILS was without an operating GS for months, and it didn't appear in the NOTAMS for the first few days.

Alternatively, is there another ILS nearby that you can fly?

[bob865]

35 minutes ago, neilpilot said:

First try to confirm that the GS isn't out of service.  Check the NOTAMS, ask another pilot to confirm operation or call the airport manager.  At my base the ILS was without an operating GS for months, and it didn't appear in the NOTAMS for the first few days. 

Alternatively, is there another ILS nearby that you can fly?

That was the first thing I did when I landed.  Per NOTAM, it's not out of service.  Next time I fly, I can try another local ILS.  I did check this when I bought the plane back in October of last year.  I lined up on an ILS just to see if the insturments worked, and they did.  So this a new development.

My next step will be to take it to the avionics guy at Winnsboro.  He is the most copetent local guy for doing actual avionics work and not just an install shop.  I feel pretty sure he can bench test the stuff and tell me what part needs work.  I was just hoping to do some troubleshooting before I go that route.  Unfortuanately I honestly don't know enough about this system to feel super confident troubleshooting it.  I generally like to know what is wrong before I ask any shop to do any work on anything.  It tends to keep them from getting off in the weeds and in turn saves me a lot of money.  Had to do this with the BMW dealership working on my fiance's car just this week.  They wanted to cut open all the wiring harnesses looking for a 'problem' which was obviously a software bug.  They weren't even sure what they were looking for, they just had no other ideas so they wanted to start looking for anything.

[Oldguy]

The alternate ILS is the least invasive as it requires nothing other than flying the plane. The test @Jerry 5TJ referenced is also non-invasive and should take about 15 minutes or so to do.

Not a lot of software in a KX155, but you might have to chase some wires. 

[bob865]

I was an old spark chaser in the marines on hornets.  I got pretty good at that.  LOL  

[jaylw314]

4 hours ago, Jerry 5TJ said:

A simple ramp test will tell if your KX155 is working.  The tech will bring an RF signal generator to the plane and apply a signal at the ILS frequency (around 330 MHz).  AM modulation at 90 Hz will cause full scale GS needle diflection.  150 Hz will drive the GS the other direction.   

What he said   It will literally take 5 minutes with the plane on the ground.  You don't even have to burn fuel while they're testing it.  They should have the test transceiver at any avionics shop, and some normal shops may have them

[bob865]

I'll have to call around.  We only have one avi shop on the field and they will never touch my plane again.  I know one shop, about 30 mooney minutes away, that has a full radio shop so I'm sure he can not only test it, but tell me if its the radio or the indicator in just a few minutes if not fully fix it.  I can dream of self tests and built in diagnostics.   

[carusoam]

There should be an audible indication that the VOR/ILS is functioning...

tune in the VOR/ILS, listen for the station IDs...?

There is a standard for this.

Something like...

• a pattern of three VOR IDs
• a fourth is the ILS ID
• if The ILS is out, there will be an empty space in the broadcast...

you probably need some moderate Morse code skills to hear them...

But you are supposed to verify what you have tuned in.  Each time.

There is nothing like the  feeling you get trying to navigate to a mis-tuned Nav signal...

how does that sound?

PP thoughts only, not a CFII.

Best regards,

-a-

[Guest]

Alternatively could you borrow another 155 from a friend?

Clarence

[carusoam]

Also...

Check to see how many radios are capable of delivering signals to the one display...

You may have a switch to tell the display what radio is doing the driving...

If Both Nav1 And nav2 can deliver signals to the HSI.... make sure the radio doing the delivery has ILS capability...

This is more of a 90s type of challenge... or older...

later boxes are GPS/VOR/ILS the switching is internal to the box...

Best regards,

-a-

[bob865]

Confirmed last night that it's my plane.  The ILS works but I still do not get a glideslope.  The Glideslope flag is gone, so I know(I assume since it is barber poled while tuned to a VOR) i'm receiving it, it's just not getting displayed.  The needle stays centered.  I'm off to find a radio shop to ground test the equipment to figure out if it's the radio, the indicator, or the wiring.  Has anyone ever had an indicator fail?  Can they be repaired/overhauled like gyro instruments?