Nose down
 

Some aircraft, A330 as an example, have a slight nose down attitude on the ground wheres others sit quite level.

I've noticed this on CRJs and MD80 series as well.

Is there any reason for this, is it a design decision at the beginning or something else?

GB

I am sure it was simply areodynamic design. The A330F has an ugly modification to raise the nose gear to compensate for loading purposes.

How about pure economics?

Needs the main leg length for landing to ensure tail clearance, but whats the point of a long nose leg? I suspect for each cm you lengthen it, it would have to be proportionally stronger, have more bracing around its mount in the fuselage and need a larger nose gear bay (=less room for other stuff!)

Just needs to be long enough to ensure engine clearance on taxi, the flip side being if you raise the nose far enough then you may decrease the ground visibility segment that is important when the fog is around and you are trying to depart.

Engineering - So many variables!

For CRJs at least, one consideration is keeping the sill of the forward doors low to avoid the expense of fitting slides to the stretched versions. So the main door stays in the same vertical position, while the back end rises for some of the rotation issues suggested above.

You must admit though that those designed i.e. the Fokker 50 and some of the shorts series werent thinking aerodynamics that strongly... They just wanted to give these beauties a character!! :E

haha
Jp