If the water is pouring out of the drain pipe, that is normal. If it's pouring out of the air handler itself, that's NOT normal and it probably means your drain pipe is blocked with dirt and algae. You can clear it most of the time with a shop vac by plugging the vent pipe which is a small stub up in the drain line near the trap usually close to the air handler and using the shop vac at the outlet where the water is supposed to drain out. This will most often suck out whatever has built up in the pipe and drain the evaporator pan at the same time. After you have cleared it you can pour a tablespoon of household beach down the vent pipe to help clear out any remaining algae. If you use the bleach once or twice a year it will keep the drain line clear.
When I lived in the deep south I had to put bleach in the drain monthly to keep the drainline clear. It kinda' shocked me that when I moved up north (Missouri) the drainlines were closed (no port to pour the bleach into)
In some installations, the drain line connects to a pipe inside the house such as a sink drain or washer. Since these lines already have vents they will often leave the vent out of the drain line itself. Also in some circumstances when the drain line is a long run the weight of the water in the pipe will overcome the negative air pressure inside the air handler and the water will flow out of the pipe without the need for a vent. In areas where humidity isn't an issue they will sometines leave the vent out. What little water collects in the pan runs out when the fan stops running and the pressure drops. This is always a gamble even with a secondary pan under the primary to catch any overflow.