What was found
FLIGHT 1897, EN-ROUTE, ON TAKEOFF WITH FLAPS 2, FLEX 54,151,000 POUNDS, HAD PITCH AXIS OSCILLATION & PORPOISING. IT WAS VERY NOTICEABLE AT FIRST, BUT DAMPENED TO NOTHING ABOUT 90 - 120 SECONDS AFTER FLAP RETRACTION. AN OPERATIONAL DECISION WAS MADE TO RETURN TO FIELD. AN EMER WAS DECLARED. A SIMULATED LANDING WAS MADE BEFORE THE ACTUAL LANDING WAS MADE TO ENSURE THAT THE PROBLEM WOULD NOT REOCCUR, NO PROBLEMS WERE ENCOUNTERED & THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. DOWNLOADED DFDR DATA & PERFORMED TROUBLESHOOTING PROCEDURES, NO FAULTS WERE FOUND. ALL SYS TESTS WERE SATISFACTORY. A FUNCTIONAL CHECK FLIGHT WAS ALSO MADE TO ENSURE THERE WERE NO FAULTS. THE FLIGHT TEST PASSED.