Here is how to use the appr mode
This might be a little confusing but you’ll get it
So, firstly some requirements you have to meet
- You must be under MLW, otherwise you are too heavy and APPR won’t turn on
- You must be under 200KIATS
- You must have intercepted the glideslope. If you are a bit lower the APPR will maintain current altitude and start coming down again once it intercepts the glideslope once again. If you are too high however, it won’t come down and if it does that at all, initiate a go-around
- You must have intercepted the localiser at a typical range of 30 degrees (for most airport approaches). Otherwise it won’t properly intercept the localiser as you come in for your final approach
Just remember these points as you plan your flight and just before you start final.
So here is how to make sure you perfectly set up your ILS approach
- Make sure you have a valid STAR and your approach as ‘IXXX’. The I indicates it is the ILS approach and the XXX basically is the runway you will be using, so choose your approach accordingly. These have the related altitudes and will help you intercept both the localiser and the glideslope without going against any airport NOTAMS or REMARKS, such as altitude restrictions. Make sure this is valid.
- (I would do this step while I am making my flight plan), go onto your arrival airport on the map, and choose your runway that you will be landing on.
- Quickly on your HUD go onto NAV and check there is a frequency under NAV1, but DON’T switch your source to NAV1, keep it on GPS so your autopilot follows your flight plan and not the approach.
- Now do your flight as normal, lets skip forward to your approach.
- As you are getting nearer and nearer, make sure that you meet all the requirements that I have listed above
- For this point, I will explain when exactly you turn on your APPR mode (for now keep flying GPS and follow your flight plan) * This might be long *
I’m not going to explain the first two requirements I listed above about when you turn on your approach as it is quite straight-forward, but the last two, intercepting the approach is key to get your APPR mode to properly function.
So, for the localiser, do not turn on APPR mode when you are at base, so do not let it turn final for you. From what I know, for it to function properly, you must be within the typical 30 degree angle that most airports have with no terrain surrounding the airport (so basically if the airport has a special ‘case’). Make sure you turn final and let your LNAV line up for you with your ILS approach that you chose in your flight plan. If you turn APPR mode on, where it says LOC underneath ‘APPR’ must be green, which indicates that you have successfully intercepted the localiser. But just don’t turn it on yet.
For the glideslope, again do not turn it on until you have intercepted the glideslope for the runway. Make sure you look at the green dot on your HUD or your PFD if you are flying in the cockpit view without your HUD next to your altitude indicator. If it is above the small horizontal dash in the middle, then you are too low. If it is below, then you are too high. You must remember an important point here; if you are too low, then it is fine if you turn it on. The APPR mode will keep you at your current altitude until you intercept it again. So if you are too low, consider it fine if you turn on APPR. HOWEVER, if you are too high, then the APPR mode WON’T descend for you, you must descend manually to a safe altitude or if you are really high, GO AROUND.
Make sure you have met the localiser within the 30 degrees bank angle and the glideslope at or under the set altitude, and it will intercept it properly for you. To confirm that you have intercepted the ILS approach successfully, make sure that the LOC (for localiser) and ALT (for glideslope) are not flashing orange, but are GREEN when you do turn on the APPR mode. If they are still flashing orange, check the green dots and check how you’re going off course.
- Once you have met all the requirements, including intercepting the LOC and ALT by looking at the green dots in your HUD, you may turn on your APPR mode. To do this, you don’t need to set your source to NAV1, it will do it for you automatically. However, if you wanted to hand-fly the plane all the way down but wanted the autopilot to control your Lateral navigation (your heading), then you do need to change the source to NAV1 in order for your aircraft to automatically keep you aligned with the runway while you hand-fly your VS and altitude.
- After touchdown, say you wanted to carry on from there, and you made a different flight plan and everything, make sure you turn your source back to GPS!!! How many times have I made that mistake? I don’t know, so I am warning you now
Thats all I could think of, I will edit my post if I remember anything else that I didn’t add.
If you think this is a bit long, try and read it out loud. This always works for me, trust me you will understand this better