Hassaan13,
Talking about GLA and B747's you're getting in to aicraft performance again which you know diddly squat about ..... at what TOW's do those B747's operate out of GLA?
I can recall circa 30 years ago, before EMA had it's runway extended, a DC10 or few operation (direct) EMA-JFK ..... now do you imagine for one minute those DC10's operated at MTOW and/or with a full payload?