4 engines vs 2 for ultra longhaul

[slim75]

Ladies, Gentlemen,

Can someone please help me understand how Singapore's A340-500 is able to fly from WSSS to KEWR nonstop but the 777-2LR can not fly that long of a leg? I'm probably missing alot of other factors here and excuse me if I am but if the triple can fly this leg of over 9,000nm why isn't it used? Thank you all in advance for your thoughts.

Cheers,

Slim

[BA 77]

The main reason is that although the 777-200LR has a longer range than the A340-500, because the 777 is wider it becomes less economical to operate an all business class service (which is always 6 abreast on SIA when it should be 7 abreast in Business on 777s). The flight is all business class which means that it is lighter, giving it a longer than specified range. Because the A340 has 6-abreast normally, more seats can be put in than an aircraft that is shorter which normally makes up for that in width.

Hope that makes sense although I'm not sure if I've explained that clearly enough.

BA 77

[Fly3]

Another reason is I believe that 4 hours extended range operations are required for some of their routes. This is dictated by the ability to suppress a fire in the cargo holds. Although both aircraft can do this, 4 hours on one engine is not allowed, hence the B777 is limited in the routes it could take and might be uneconomical on many days.

[slim75]

Thanks a bunch BA77 and Fly3 for your responses.

Cheers,

Slim