Originally Posted by
jmmoric
and I've had 737's land with tailwind more than 10 knots.
It is not, that you physical can not land with higher tail winds. The problem is that the ground speed is the tailwind component higher than your IAS (Which makes your airplane fly).
So the normal 3 degree slope will need to be less than 3 degrees and you run faster out of runway because your touch down speed is by the tailwind component higher. So you need a longer runway, the slope should be lower than 3 degrees which often terrain clearance, noise abatement, ILS slope and procedures do not allow for, and your touch down ground speed is higher, which might be limited by tire rating and breaking performance.
The theoretical lower than 3 degree slope needed for tail wind also mean, if you are high on a 3 degree slope with tail wind, forget it. You need much more runway with tail wind and if you touch down late...