CLB THROUGH ASSIGNED ALT AFTER A DEST CHANGE. ALTDEV ALT EXCURSION.

Narrative

BEFORE DEP; I WAS ADVISED BY MY BOSS TO CHK THE WX IN DALLAS; SHREVEPORT; AND LONGVIEW. 30 MINS PRIOR TO DEP I WAS ADVISED TO FILE IFR TO LONGVIEW. I DEPARTED TEXARKANA; AT ABOUT XA45 WITH AN IFR CLRNC TO LONGVIEW. MY IFR CLRNC WAS 'AFTER DEP; CLRED AS FILED; CLB AND MAINTAIN 2000 FT; EXPECT 6000 FT 10 MINS AFTER DEP.' AT APPROX 1300 FT; MY BOSS; WHO WAS SITTING IN THE FRONT R SEAT ADVISED ME TO CHANGE OUR DEST TO SHREVEPORT. WHILE STILL IN MY DEP CLB; I RADIOED ZFW AND REQUESTED THE CHANGE IN ROUTING. ZFW TOLD TO ME TO STANDBY FOR MY NEW CLRNC. AT THIS POINT; I WAS STILL BELOW 2000 FT. FORT WORTH QUICKLY RETURNED AND ADVISED ME I WAS CLRED TO BELCHER VOR; THEN DIRECT SHREVEPORT. I CHANGED MY HDG TOWARDS BELCHER VOR AND CONTINUED TO CLB. AT ABOUT 2800 FT; ZFW ASKED ME MY ALT. I READBACK 2800 FT. FORT WORTH SAID I WAS SUPPOSED TO MAINTAIN 2000 FT. I TOLD THEM I THOUGHT I WAS CLRED TO 6000 FT. I THEN ASKED THEM IF THEY WANTED ME TO DSND BACK DOWN TO 2000 FT. THEY ADVISED ME TO CONTINUE MY CLB TO 6000 FT. ABOUT 5 MINS LATER; I WAS GIVEN A PHONE NUMBER TO CALL ZFW WHEN I LANDED IN SHREVEPORT. ON THE GND; I TOLD THEM THAT I DID NOT HEAR THEM SAY MAINTAIN 2000 FT. WHEN THEY ISSUED MY NEW CLRNC TO SHREVEPORT - I ONLY READBACK DIRECT BELCHER VOR DIRECT SHREVEPORT. THE ACTION OF NOT MAINTAINING 2000 FT COULD POSSIBLY HAVE BEEN DUE TO MY BOSS TALKING IN MY EAR WHILE ALSO TALKING TO CTR; AND RECEIVING A NEW CLRNC IN MY DEP CLB.