SKBO RNP X 31L

[Samaritano]

Just completed a flight from SVMI to SKBO with ATC-X Pro. I got assigned RNAV approach X to 31L. I was flying the FSL A320SL. There were thunderstorms approaching Bogota. Question for the experts how does one fly an RNP approach. From what I've seen you do not select APP on FCU. I did that and also change VDEV. Everything was going well until the A/P disconnected on its own. Is that a normal behavior for the Airbus A32X? I tried flying it manually but I was all over the place. The A/T kept going into A.Floor.

For those that want to try the approach I landed around 2240 zulu and used Active Sky for weather.

Here is the chart.

 

[snapshot21]

You have to select APP in order to arm the FINAL APP mode and for it to follow the glidepath down. Do it before the FAP which is BO708 in that approach.