Aseem wrote:

---

 what can be the reason behind not going for B787? 

---

As an aircraft engineer working on structure repairs i always wondered about the reliability of repairs on composite structure fuselage. The amount of bashing a fuse endures around the L2 & L3/4 doors on pax a/c, due to step ladders and aerobridges, cost airlines a whopping $3b/yr (I'll post the link soon), apparently Boeing had to do a lot of tough convincing to airlines on this count during their marketing campaign.  

Based on the above it makes sense to get sufficient lift (19xA333) to sustain growth at a competitive price ( enough to offset any losses from higher CASM seat mile costs, leahy has already mentioned this regards the A345/6 ) till the new tech has proven itself. If tech comes good, buy it as they would have ramped up additional manf lines, delivery lead times wont be longer than 5yrs, 2009 orders would be delivered around 2014/2015 considering complete stoppage of B757 & B767lines by then. If otherwise, you have minimum disruptions compared to competition. 

A350XWB being a metal aircraft THIS particular problem is not an issue, if the B787 proves itself and provided SQ still retains its same position in global aviation (which i doubt due to the INDIA factor) Boeing will once again do a swap similar to the A343/B777 it did for SQ.

Where do i put my money, won't put it, i am just a bleeding maintenance engineer not a design or manufacture man. My 2p.........