Delta at MAN
 

Does anyone know what happened with the delta flight departing earlier?


it took ages to get on the runway, then did a slow taxi, down the runway and went back to the gate, meanwhile the QR did a go around, because of it, does anyone know what happened ?

I don't know what happened with that particular flight, but from what you wrote it sounds to me that there was some kind of engine trouble during the pre-takeoff engine runup. That's just my non-expert opinion, of course.

"the pre-takeoff engine runup" - yes, definitely a "non-expert opinion".

I know this is a rumour network, but PLEASE!

Perfectly plausible
 

And why not?????

It would appear that you're the ill informed, otherwise you'd be aware that in freezing temperatures, after taxiing in icing conditions, an engine run up should be carried out prior to departure to shed any ice that has formed on the engine fan blades.

I apologise! I did not know that. Do all jet engine manufacturers recommend that? Presumably it is the same for turbo-props as they effectively have the same type of engine?

I can't remember ever doing run-ups in the TP that I flew, however it was in the dim and distant past. I also couldn't honestly say whether a run up is required by all engine manufacturers and for all different types of engines that they produce, but I'd place bets that most would require it.

Watched a B747 (400) at my local airport "rev up" for a good 10-15 secs or so before releasing the brakes the other cold and icy evening. Thought that the crew mistakenly believed they were flying an IL-76, but now I know why.