LRC vs ECON (B757 Style)
Joined: Sep 1999
Posts: 5,552
Likes: 25
From: ME
MRC is basically the greatest distance per kg fuel.
LRC is approximately 99% of this distance and is generally a more stable cruising speed than MRC.
Now lets look at Cost Index, this is designed to save MONEY, its a trade off between the aircraft cost and fuel. In our case fuel is cheap so we should fly as fast as possible, using more fuel and saving time!
So i can truthfully say that in our theoretical case, LRC saves more fuel than Cost Index!!!!
For a reference, look at the top of this thread for the J_T list of useful sites, then look for the "Airbus, getting to grips with Cost Index"...
Mutt
LRC is approximately 99% of this distance and is generally a more stable cruising speed than MRC.
Now lets look at Cost Index, this is designed to save MONEY, its a trade off between the aircraft cost and fuel. In our case fuel is cheap so we should fly as fast as possible, using more fuel and saving time!
So i can truthfully say that in our theoretical case, LRC saves more fuel than Cost Index!!!!
For a reference, look at the top of this thread for the J_T list of useful sites, then look for the "Airbus, getting to grips with Cost Index"...
Mutt
Thread Starter
Joined: Aug 2002
Posts: 508
Likes: 16
From: Under the sea
Thanks Mutt, I'll have a look.
I think this is the perfect aviation topic where the answeer is, "Well, it depends". Came up the other night flying in LRC at FL360 with over 90 knots on the nose. Slowing down into that wind can't save money.
Big Boeing FMC Guide suggests that ECON will save more gas than LRC.
I think this is the perfect aviation topic where the answeer is, "Well, it depends". Came up the other night flying in LRC at FL360 with over 90 knots on the nose. Slowing down into that wind can't save money.
Big Boeing FMC Guide suggests that ECON will save more gas than LRC.
Last edited by extreme P; 20th July 2006 at 19:38.
