Narrative:

At liftoff from mco runway 17 we got GPWS terrain warnings. (XA24 local time) we were vectored to intercept the jag 2 departure. On our map display it appeared we would intercept just prior to mateo. The controller (jax) asked where we thought we would intercept the departure (J-53). I told him just before mateo, he said we were already west of J-53 approaching military airspace and vectored us back to the east. I immediately selected crg VOR manually and confirmed our position west of J-53. We quickly intercepted J-53 and continued with manual VOR navigation. I advised ZJX (the next controller) we were no longer /east, but were VOR navigation only. We did a navigation accuracy check off of dbn VOR (144 degrees/68 NM) while our inertial navigation showed (158 degrees/96 NM). A 14 degrees/28 NM error! On deck in atl, the navigation accuracy error was 29 NM. We believe aircraft position shifted at automatic update on the takeoff roll. This accounts for the terrain warning at liftoff. I have never heard of or seen anything like this in a B757 or B767. Maintenance thought a recent lightning strike might have something to do with it. Learning point: a navigation accuracy check after takeoff is a good idea, and should definitely be performed if a GPWS warning occurs at liftoff.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.