Originally Posted by
djohannw
It's (as guessed) indeed FRA-IAH, and it is for early October 2015. I have seen all the charts kindly provided by mduell but sadly fail to understand what they are supposed to say, especially the third table.
I have been doing this flight a few times in 2014 late summer to winter, and so far actual in-air times have not varied that much from the mentioned timeframe on the flights I have been on - plus FRA is certainly not an airport where you depart within a few minutes after pushing back. So I fear that the 45 minutes reduction is not really achievable by just changing the equipment to a 772...
No, the 45 minutes is not achievable JUST by changing the equipment to a 772. It IS achievable by also factoring in that October is still IATA Summer and sees some of the lowest head winds of the year. You cannot compare a winter block time and a summer block time and assume that the difference is all equipment.
An almost universal rule for east-west flying is westbound block times will longer in winter than in summer (v.v. for eastbound).
That said, on any given day, a lot can happen. The block time can still be "correct" in that the desired percentage of flights in a season have actual block times equal to or less than schedule and yet on your day, you end up 30 minutes or even 60 minutes over.