BERLIN HEDGEHOPPING TO FREEDOM REFUGEES FROM BEHIND THE IRON CURTAIN HAVE COME INTO WEST BERLIN OVER ROOFTOPS AND UNDERGROUND, BY FOOT, AUTO, TRAIN, BUS, BOAT AND ARMORED CAR . LAST WEEK WEST BERLIN WELCOMED THE FIRST TO ARRIVE BY PLANE POLISH AIR FORCE MAJOR RICHARD OBACZ, 34, HIS GERMAN-BORN WIFE MARY, 27, AND THEIR TWO SMALL SONS . A JET TEST PILOT STATIONED IN NORTHEAST POLAND, MAJOR OBACZ RECEIVED OFFICIAL CLEARANCE TO LOG EXTRA FLIGHT TIME BY FLYING HIS FAMILY TO VISIT RELATIVES IN SZCZECIN (FORMERLY STETTIN), ON THE EAST GERMAN BORDER . OBACZ CRAMMED HIS WIFE AND TWO SONS, LESTER, 9, AND CHRISTOPHER, 5, INTO THE REAR SEAT OF A PROPDRIVEN, TWO-SEATER TRAINING PLANE . ONLY AFTER THEY WERE ALOFT DID HE TELL THEM OVER THE PLANE'S INTERCOM THAT HE WAS MAKING A BREAK . TO AVOID COMMUNIST RADAR DETECTION, HE HEDGEHOPPED OVER THE GROUND, NEVER FLEW HIGHER THAN 150 FT . THROUGHOUT THE ENTIRE 150-MILE TRIP . WHEN ONE POLISH GROUND STATION CALLED FOR HIS LOCATION, OBACZ DID NOT REPLY . AN HOUR AFTER TAKE-OFF, OBACZ ROARED OVER WEST BERLIN'S CHECKPOINT CHARLIE AT ROOFTOP LEVEL, LANDED AT TEMPELHOF AIRPORT, AND REQUESTED POLITICAL ASYLUM . " I FLED BECAUSE I WAS FED UP, " OBACZ SAID . " I WAS TIRED OF PRESSURE . I WANTED TO WORK TOWARD TRUTH . WE WANT THE RIGHT TO TRAVEL WHERE WE WANT, THE RIGHT OF FREE SPEECH, THE RIGHT TO WORK FOR A GOOD CAUSE . "