Having seen radar altimeter option on SR2, I got an idea that same code can maybe be used for reliable ground effect. It would add a certain amount of effectiveness to wings when close to the ground. Of course, it wouldn't be sudden. Lift would steadily increase as you approach the ground.
For those of you who haven't heard of ground effect, here's a Wikipedia article on the subject.
A few weeks ago, i was testing the DE1, and i had a quadruple engine failure following a tail strike, it was then that i saw, the aircraft took off, but stopped climbing at it’s wingspan altitude. When it passed the overrun part of runway 09 of DSC, it started descending due to the absence of close ground. (Obviously it ditched in the water cos: no energy) i am 95% sure that this was caused by ground effect (the other 5% is coincidence)