APR Button lock

Using ILS mode on landing, the APR button appears “lock”. What this means?

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It says “LOC” which means Localizer. The localizer is the straight-in that is aligned with the runway. It is trying to intercept that. I believe it also says “GS” which means Glideslope. The glideslope is the path that the aircraft follows in descent, usually a 3 degree downwards angle from the start of it. Hope this helps!


First of all, thank you. The problem is that when I press the “APR” button and “LOC” appears, it disables the entire autopilot.

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What exactly do you mean it disables it?

Yes, it’ll automatically try to take you to a heading to intercept the Runway ILS.

You’ll always want to be at a 30 degree angle or less at the top of the runway cone. Like if it was runway 10, it’s heading would be 100, therefore, tuen heading 130 or 070 depending on the aide of the runway your on, then turn on APPR :)

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The problem is that when I press the “APR” button and “LOC” appears, turn off autopilot.

Does the aircraft pitch up or make a turn?

When APPR mode of AP is active it takes control of heading and VS. Attitude is set off, as well as VNAV. Speed stays under your control either via Throttle or setting in AP.

If it works as it should AP button, VS button, and APPR button are orange, speed button if you have set. When LOC is intercepted should turn green. When GS is intercepted it should turn green as well.

If all that is not the case you did something wrong and more information from your side ids needed to investigate.


the aircraft loses control - without the autopilot - and goes into stoll

At what speed are you activating APPR?

Thank you very much. I’m trying to investigate. All procedures are being done as I have always done. This “LOC” warning had never appeared before. I tried twice later to see if I did something different. but so far everything is still going wrong. But I appreciate your comments.

I am activating APPR at speeds between 180/160, depending on conditions.

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Thats a bit slow for activating it…

Try activating it at around 200ias

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It is not a warning, it is a status.
orange, not intercepted
Green intercepted and active

For the GS you should keep in mind that it should usually been intercepted from below, in that case VS could been keep at 0 as it is set by activating APPR.
If you are going to intercept the GS from above you need to set VS manual to something larger the 800fpm after activating APPR. This is a new feature, before 20.3 it was just fixed to 0fpm and you never intercepted the GS when above it result in a missed approach.

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Ok Thank you. I will try 200 ias.

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Also, i find that in order for the plane not to pitch up, you have to intercept the glide slope either close to perfect or a bit high. What you described, that the plane pitches up and stalls, sounds like what happened when i tried to activate APPR when i was too low

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160-180kts is fine, I usually do that.


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