Hello AllIusually start my 737NG 800 with engines running. Still not confident that I can master a'cold and dark' start. Anyway, in about 50% of cases, I find that the A/T will not arm. Instead, one of the three warning lights "AT first" glows a steady red. I cannot work out the cause of this. Any advice much appreciated.ThanksSimonps. What is sel/oat and how do you calculate correct value for entry on N1 page?

Simon,Check that your engine driven generators are online. The indicator lights are on the overhead and should be dark when the gen's are online.(I wonder how many times I've written these lines) ;-)I know it helps,