MLG CREW HAD TRACK DEV.

Narrative

DURING TAXI OUT; THE FO AND I PREPARED FOR TKOF FROM RWY 5L AS ADVISED BY GND CTL ON INITIAL TAXI INSTRUCTIONS. PERFORMANCE CALCULATIONS WERE MADE FOR RWY 5L. AT THE LAST MIN; AS WE APCHED THE INTXN OF RWY 5R WHERE WE WERE TO CROSS AND PROCEED TO RWY 5L; WE WERE GIVEN A CHANGE OF INSTRUCTIONS. AT THAT POINT WE WERE CLRED FOR AN INTXN TKOF ON RWY 5R. WE ALSO THINK WE MAY HAVE BEEN GIVEN AN INITIAL HDG TO FLY AFTER TKOF; BUT NEITHER OF US IS SURE OF THIS. THIS SUDDEN CHANGE NECESSITATED SOME QUICK REBRIEFING AND PERFORMANCE CONSIDERATIONS AND CALCULATION WITH ADDITIONAL CONVERSATION. AFTER TKOF; I FLEW THE RWY; HDG AND WHEN WE SWITCHED TO DEP; THE FIRST THING HE SAID WAS; 'WHAT WAS YOUR TWR ASSIGNED HDG?' THE FO RESPONDED THAT IT WAS RWY HDG; BUT AFTER A FEW MINS OF TRYING TO RECOLLECT; NEITHER OF US WAS 100% SURE OF THE HDG ASSIGNMENT GIVEN WITH THE TKOF CLRNC. NOTHING MORE WAS SAID TO US ABOUT THAT BY DEP CTL. IN RETROSPECT; WHEN GIVEN A SUDDEN CHANGE OF DIRECTIONS AND CLRNC; I FEEL THIS SHOULD BE THE TIME TO ACTIVELY SLOW YOURSELF DOWN SO AS NOT TO MISS ITEMS OR MAKE MISTAKES. AS ALWAYS; ANY RUSH TO ACCOMPLISH TASKS IS RIPE WITH OPPORTUNITY FOR ERROR. AGAIN; I'M NOT SURE WE DID INCORRECTLY FLY THE INITIAL TKOF. THIS RPT IS SUBMITTED AS A LESSON LEARNED.