cdpohl1

Thanks for all the input and help from your side. I'll try to keep all this in mind. My last flight was successful, VNAV and LNAV worked fine, although I now tend to deselect VNAV on reaching top of climb.

Hi Jan, Again thanks for your input. I have heeded what you recommended and succeeded finally to complete the flight. What did I do? On attaining FL180 ( Simbrief recommended FL200, which I changed it to FL180), I deselected VNAV and continued on MCP speed (reduced it from 330 to 280), and the for descent I used V/S, as suggested by you. Lo and behold, I managed to sneak into EBBR. I was very happy to finally succeed, as you can imagine. I do think, however, things are not what they should be. For example, if you continue on a path that is dangerous, there should be warning bells, or some other indication. Why would the plane suddenly reduce its speed and stall without any prior warning? Really has me baffled. Nonetheless, I will now try other flight sectors to ascertain that the settings I used work. If they do not, I will get back to you, and I hope you don't mind. Thanks again for your help.

Ok, thanks for your reply. I did reach FL200 just north of DIK, still quite a ways from TD. On reaching FL200, N1 disappeared and so did VNAV. The speed then quickly reduced and the aircraft stalled.

Have difficulties attaching small jpeg files. Will keep trying.

Right, here we are again. Repeated again the short flight ELLX to EBBR, and, believe it or not, encountered the same problem again. N1, VNAV and LNAV engaged and climb-out fine until I reach FL200 when all hell breaks loose again. Soon after I find myself in pieces back on the ground, still breathing, though. I have attached a zip file with pictures, and hope someone can shed light on what the heck I'm doing wrong here. Thanks in advance. Photos(1).zip

Thanks to all who responded. I guess I must be real stupid, but I just had the same problem again on a short hop from ELLX to EBBR, when the plane, on passing FL160, rapidly reduces speed and subsequently stalls. I used the Tutorial 'Full Flight with FMS' as guidance. Used SimBrief for my briefing. Here a short description: ZFW 46.3, Gas 4.9 with 2 as reserve, cruise level FL200. Settings on takeoff: Both FDs on, A/T armed, N1 engaged for takeoff. LNAV engaged after airborne. Unable to select VNAV. No problem thus far, aircraft climbing. N1 changes to SPEED. Increasing speed on MCP to 270 passing FL100. Aircraft is slowly increasing from 230 but does not reach the set speed of 270. Rate of climb reduces steadily, then speed reduces quickly and a stall occurs. No icing present. I'm kinda annoyed now since it has happened so many times. I will try and record the settings on my next doomed adventure. Meanwhile thanks again.