LNAV vectoring mistakes

Can someone help identify where I am going wrong and correct my mistake please. Each time I file more than one flight plan per flight, after my second take off, my navigation system will not pick up the new flight plan. eg: Flying approach to destination as filed in my flight plan > Land at destination either visual/ILS or manual/autoland - ILS set to nav. 1 for chosen RW > clear FLP while on ground > file new flight plan to next destination > After takeoff, select LNAV....... At this point I assume that the aircraft would recognise the current FLP and so would vector onto the nearest leg. However, the aircraft banks away or across the path an back towards the airfield.

The aircraft lines up with the localiser of the runway (set in NAV 1) then flies RW heading while in climb or at current alt.

I am certain that i am doing something wrong when clearing NAV for the previous landing, and that clearly that over-rides the new FLP.

Can someone explain to me how I would restart the flight planning process properly when I fly more than one route in a session?

You need to reset your nav source to GPS, which you didn’t according to what you said.


Thank you!