Hi all,
in
A320 Sim Pilot creates a flight plan in MSFS2020 and specifies RNAV 09L-Z at EGLL for landing.
At 13:08 he programmes the MCDU with information re the APPR phase (QNH, Wind etc) and at 13:48 he activates it.
My question is, do you have to do that MCDU APPR programming in MSFS2020 to do a successful RNAV landing? I would have thought that MSFS2020 would have automatically inserted that information after you created the flight plan initially.
MSFS does insert most of the data needed for a RNAV approach but it does not insert:
I always insert these and I’m interested as to how a RNAV approach can be used if you don’t insert them mainly because in low temperatures (below ISA) the flight path angle is less shallow in lower temperatures ie its less steep, the Airbus systems cannot (as I understand it ) detect that shallower angle.
Also some Approach charts will have a restriction on them where the temperature is below 10c for a RNAV approach
Having said the above I will try a RNAV approach without these inserted and report back later
Please note I am not a real life pilot
I’m not sure what you mean by flight path angle, but your descent angle has nothing to do with temperature.
RNav just determines where a plane is by using all types of measuring equipment, and then compares it to where it should be, and aims for that spot.
The three items you mention that are required for all landings.
MDA is basically for pilot usage, it isn’t really necessary to land the plane.
Wind speed is used by the pilot to determine Vref and approach speeds, higher speed is required for higher winds, as you probably know!
It doesn’t make much difference in MSFS if it is entered or not.
QNH obviously affects the altimeter so it needs to be set.
Generally, IRL you have a good idea which runway you may be landing on, upon arrival, in your preflight briefing.
That frequently changes in flight due to weather and runway availability.
In some aircraft, the autopilot does not like to be pre-programmed for the arrival, and won’t operate correctly if that is done.
So as you can tell, most times the arrival is indeed programmed into the A/P when that clearance is given by ATC.
However, having said that, you don’t have to do it. You can program it in at the start, if you want to.
MSFS doesn’t know what approach you will be using, so it can’t automatically enter that info.
Ok thanks for the clarification…
Couple of points CaptainBjarnason(Sighvatur Bjarnason - YouTube) here describes the point I was trying to make viz low temperatures on RNAV approaches time stamp 13.53 --15.04 think it is
I have done both and from experience:
If you don’t insert the wind info then the runway lineup will be off by a few degrees in high winds
If you don’t insert the MDA or DA you won’t get a “minimums” callout
For the QNH and Temp I was not able to see any difference from entering or not entering it. However, I am still getting to grips with the A320NX and RNAV approaches so it’s possible there is a difference. I also found that entering the information given by ATC or ATIS is prone to error so I use the latest METAR. Since the last update this seems to be accurate to what the ground weather is in the sim, even if that disagrees with what ATC or ATIS are telling you 
thanks good points
What site for METAR info do you use?
What he is talking about is reliability of VNav (vertical navigation) when temperatures are below published chart arrival procedures.
Due to barometric issues at quite low temps, you won’t have reliable enough altitude positioning , so an RNav approach is not allowed.
ah ok thanks again
Completely unrelated to the OP, but was wondering:
I assume the G3000 and other nav units use the given QNH and outside temp so you don’t have to enter this info?
You don’t need that callout to land, it is a reminder that this is your last chance for a go-around.
It really doesn’t make any diff if you enter the wind speed.
I always enter the metar of the arrival airport, and unlike yours, in my sim most time it isn’t even close to the weather MSFS is displaying, so I am always different, and have had no issues with “off a few degrees”.
I don’t believe any A/P, even IRL, is sophisticated enough to fine tune its ability depending on current wind conditions.
This is mainly done in larger aircraft that specifically require this data to be entered separately in the FMC.
Keeping your QNH as per ATC is fine.
I think it’s hit and miss with regards to Metar’s and the actual weather displayed in MSFS. Using the Unreal Weather mod it is 100% a hit of course, as that uses Metar’s to create the weather around the plane 
All I can say is that after some dodgy landings with sidewinds and winds from behind I stopped believing what ATIS said, for sure (when flying without ATC control) and so used Metar’s to decide which runway to use on arrival.
The only thing I find with addon weather engines is that they can have some rather abrupt transitions from one area to the next!
I stick with the default to avoid this!
Ok thank you. I wonder if this is even modeled in MSFS. Next flight I’m going to try to land with QNH way off and see if it makes any difference.
Let me know how it goes!!
Thanks for all the replies.
Q1. How do you find out the wind at the airport you’re flying to? I often just use clear skies and not live weather, so I need to find out what the SIM is making the wind at the destination.
Q2. If ATC is giving you QNH of 29.92 In Hg but the "Weather* drop down says 1013 Hpa, which do you put into the MCDU?
The A320 is metric, so 1013 is correct.
If you use the sim’s planner, the wind is shown on the world map at your destination runway.
The other thing you can do is just do an internet search for your destination’s metar. It should be similar enough to the sim weather to use.
If you are using the mod, the CustomFbW has a function to ask for the metar in the MCDU.
I’m not sure if the other two types do.
If you’re using the Clear Skies preset the wind is same everywhere. I can’t remember it exactly but, as previously stated, it’s shown on the World Map for both airports in your plan. Something like 225 degrees at 3 knots? (maybe 7 knots?) Anyway, you can check it there and it will always be that setting if using Clear Skies.
That is correct!