I understand what you are saying Lis but I think its most likely to be "the x-plane dataref bug". Sometimes or around once every month for me I get this problem when for example the right engine starter doesn't work and my left one does or my nose gear doesn't move. Every time its something different and can be put right by restarting the sim. My understanding is that I'm not the only person who has had this problem. I hope it gets fixed in V10 :