ILS problems

[87-205SE]

KFC 150   Avidine 540   G5 HSI

The airplane will fly a non precision approach perfectly including the hold and vertical  guidance if available.    The entire approach to the FAF.  

ILS is a different matter.   Select and program destination.  Select but do not activate ILS approach.   Utilize either nav mode or hand fly to set up a 30 degree intercept to the ILS, 

Engage autopilot, activate ILS approach, Nearing intercept select approach button.  Approach light blinks until localizer established.   Altitude and heading lights go out and approach light remains steady.   GS light comes on.      Intercept the localizer on the G5 (green)   VLOC selected.....GPSS both on and off, we have tried both, aircraft starts to track the localizer and then either turns right or left off the localizer.    I am pretty sure it is operator error, but I have read all the manuals, the KFC is functioning exactly as described, but it won't fly a simple ILS.   We can always hand fly, but after spending a bunch of dough, we are both engineers, we would like to watch our toy perform.      Any ideas????

Next step is probably a call to the avionics shop, but I don't think any of those guys fly.   Hopefully I can talk one of them into a demo ride as there is an ILS at their non-tower controlled airport.

[N201MKTurbo]

Did you select the localizer input on the autopilot? When you are in GPSS you are in heading mode on the autopilot, you need to switch the autopilot to localizer. Did your avionics shop hook up the course error signals to the autopilot or just the GPSS?

[87-205SE]

Thanks Bud....will advise

[87-205SE]

GPSS off..........ILS frequency checked and selected automatically.   VLOC selected turning g5 HSI green.    Luckily we have a #2 backup and after 35 years of flying, it's a breeze.   Too much technology sometimes.  Info overload.   Hand flying the ILS stone simple anyway.   Thanks

[PT20J]

How fast are you going? My KAP 150 had trouble capturing the localizer in APR mode and would overshoot in each direction unless below 90 kts. I used to capture in NAV mode and switch to APR once established.

Skip

[Ibra]

 @PT20J is right like all analogue AP, KAP150 needs to be watched or supervised (a good thing to do) for localiser capture in APR mode, if you are going fast or wind angle is big it MAY lose it, one “simple fix” is to intercept with NAV mode and switch to APR mode once established, say 2nm before FAF

This is no different than how a digital AP would fly on GPS LPV: the navigator will be in ENR or TERM and flip to LPV sensitivity once you are established and 2nm before FAF, the AP tend to love this 

It’s the same as your default setting for GPS/VLOC switch on procedural ILS, it flips to green 2nm before FAF, also ATC rarely vector you on ILS earlier than 2nm, in other words you will never miss anything no matter how you fly that ILS 

On vectored ILS: I put HDG bug, HDG mode, arm NAV for any early (fast) intercept, then flip APR once established on VLOC 2nm before FAF 

On procedural ILS: I put GPS, NAV mode, arm APR, then let GPS does NAV/APR & GPS/VLOC switching…

Edited December 26, 2021 by Ibra

[carusoam]

KAP150 may be digital… (?) but…

Its computing power, speed, and memory… are incredibly small.  Early 1990s PC style…

Expect to easily overload its capabilities…

Technically, it should be able to intercept the glideslope, even from above…

The operations manual is very specific on when to hit which button… and when it may be too late to achieve capture…

and what each flashing button means…

 

As far as the G5 goes… is it set up properly, and have all the hardware to support this?  (Not all G5s are, individual installation details are important)

Best regards,

-a-