Yeah right. Winglets are no real use.....So please provide a proof source for that statement.
CDL 8.57-1
b) Complete Wing Tip Fence
One may be missing provided:
1) exposed interior structure is covered, and
2) takeoff and approach climb limiting weight is reduced by 4%, and
3) fuel consumption is increased by 1,4%, and
4) wing tip fence must be replaced at the earliest maintenance opportunity and meanwhile, protective material must be inspected, before every flight and replace if necessary.
5) reduce one engine inoperative ceiling by 300ft.
Maintanance procedure required prior to each flight.
Hope this evidence is convincing enough.
So long,
DBate