Tail-take-off,
may I ask what you would like the engines to do if you do forget to set a flex temperature?
declaration of interst here as I am looking into future automatic responses and one of the scenarios is just that.
Currently as far as I can see there is a nagging message which asks for either a temperature to be input or TOGA to be selected on the TLs.
VnV
(but of a misnomer now as I have been 'promoted' to systems stuff)