Unexpected V-speed deletion

[Guest Nightflight744]

Hi guys!I have a problem with the V-speeds of the B747-400 and also the F version. The problem happens since I fly online on VATSIM. When I flew offline I always lined up, hold short on the runway and then began the takeoff (V-speeds confirmed, A/T armed, manually to N1 70% and then the TOGA button, everything went fine!). Online I often get the takeoff clearance while taxiing and then I begin the takeoff roll without an additional stop on the runway. Then the awful thing happens. When trying to engage A/T with the TOGA button suddenly all V-speeds are deleted. My only chance is to reconfirm the V-speeds during the takeoff roll. Shouldn

[downscc 1,327]

I takeoff on the roll often in the 737, so I assume that the operation itself isn't the problem.

[Guest Nightflight744]

It shouldn

[Guest dt1951]

Hi Fabian. Man oh man! I have mentioned this issue before. I have no idea either. It was happening to me quite frequently with the 744F version. After getting past 80% N1, I would push the engage button (the screw head) and the V-Speeds would be immediately deleted. No one has produced a satisfactory answer for that issue. I feel your pain after spending a good amount of time doing the flight prep work. But the issue seems to have disappeared. I wish I could say that I am now doing something differently, but I don't think so. Once the V-Speeds get deleted, I didn't know how to get the autothrottle engaged. Pushing the screw head didn't work. So I simply exited FS.