B767-200 CREW HAD A TRACK DEV DEPARTING MCO ON THE JAGURE THREE SID; AFTER THE CREW DID NOT BACK UP FMC POS WITH RAW DATA.

Narrative

AT LIFTOFF FROM MCO RWY 17 WE GOT GPWS TERRAIN WARNINGS. (XA24 LCL TIME) WE WERE VECTORED TO INTERCEPT THE JAG 2 DEP. ON OUR MAP DISPLAY IT APPEARED WE WOULD INTERCEPT JUST PRIOR TO MATEO. THE CTLR (JAX) ASKED WHERE WE THOUGHT WE WOULD INTERCEPT THE DEP (J-53). I TOLD HIM JUST BEFORE MATEO; HE SAID WE WERE ALREADY W OF J-53 APCHING MIL AIRSPACE AND VECTORED US BACK TO THE E. I IMMEDIATELY SELECTED CRG VOR MANUALLY AND CONFIRMED OUR POS W OF J-53. WE QUICKLY INTERCEPTED J-53 AND CONTINUED WITH MANUAL VOR NAV. I ADVISED ZJX (THE NEXT CTLR) WE WERE NO LONGER /E; BUT WERE VOR NAV ONLY. WE DID A NAV ACCURACY CHK OFF OF DBN VOR (144 DEGS/68 NM) WHILE OUR INERTIAL NAV SHOWED (158 DEGS/96 NM). A 14 DEGS/28 NM ERROR! ON DECK IN ATL; THE NAV ACCURACY ERROR WAS 29 NM. WE BELIEVE ACFT POS SHIFTED AT AUTOMATIC UPDATE ON THE TKOF ROLL. THIS ACCOUNTS FOR THE TERRAIN WARNING AT LIFTOFF. I HAVE NEVER HEARD OF OR SEEN ANYTHING LIKE THIS IN A B757 OR B767. MAINT THOUGHT A RECENT LIGHTNING STRIKE MIGHT HAVE SOMETHING TO DO WITH IT. LEARNING POINT: A NAV ACCURACY CHK AFTER TKOF IS A GOOD IDEA; AND SHOULD DEFINITELY BE PERFORMED IF A GPWS WARNING OCCURS AT LIFTOFF.