The senate is more conservative than the house, but based on the overwhelming support the bill got in the house I'm pretty sure the senate will pass it also, perhaps by a smaller margin.

The only question is what will get traded away to reconcile the house and senate versions. There is language in at least one version allowing pilot academy grads to substitute classroom hours for flight hours!

As to the original question...assume it will pass no later than June. The recent NWA and AA incidents will light a fire under the senate bill I suspect. So for planning purposes the ATP requirement will kick in by about June 2015.