THERE CAN BE no more grueling port of entry into Greater Washington than National Airport, where pilots can pull up and let out passengers far more easily than anyone behind a steering wheel at ground level. But Getting There is only half the horror. Getting back is often another kind of adventure in space: Even if you're lucky enough to be bundled into a cab with others headed for the same hemisphere, your vehicular host may not have the foggiest idea of how to take you where you said. Your first problem is that you gave the directions in English.

We've been in cabs where the driver can't tell the difference between the Capitol and the Kennedy Center, or between the Washington Monument and The Washington Post. And when they get that part right, you still may wind up crossing the Potomac at Cabin John and turning right at Hagerstown. Is there anything that can be done to make English and geography prerequisites for Hacking 101?

In the District of Columbia, maybe; D.C. Council member H. R. Crawford is pushing legislation that would stiffen the testing for a hacker's license. (It also would limit the number of drivers, which is not a good idea.) Anybody who is sore enough to sound off on this subject is invited to testify at a public hearing scheduled for 2 p.m. and 6 p.m. on Monday, Oct. 22, by calling 724-8077 no later than 5 p.m. Oct. 18.

But whatever Mr. Crawford and the D.C. government may do about testing won't solve that much at National, where all sorts of people seem to pose as cabdrivers and get away with it, at least until they've got you on the road and out of sight of the airport. What about their credentials? Can't those police officers, cab starters and others who weave and wave their way through the traffic lanes do a few checks on these "cabbies"? How about spot checks on licenses and insurance -- and arrests of those who have no business doing business?

Again, we're not talking here about the majority of area cabdrivers, who take pride in doing an efficient, courteous job of moving people in, out and around town. They, too, are hurt by those who don't play by the rules or don't know what they're doing. It's crackdown time.