Originally Posted by
BelmontRef
Yes, given that the OP even said he was comparing current time to some unspecified "far future" date, there is almost certainly some seasonal variation in there as well.
For a flight with a near 12 hours block time, a 30 minute difference between 777 and 767 sounds about right. Throw in 15 minutes of seasonal change and 45 minutes could well be right. If the OP would tell us what market and what dates, a better response could be provided.
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...
Greetings - Dirk