AN UNEXPLAINED CHANGE IN CTLRS IMMEDIATELY AFTER TKOF LEADS CREW TO THINK THERE WAS CONFUSION IN THE TWR ABOUT WHICH ACFT WAS GIVEN WHAT HDG AFTER TKOF.

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FLT DEPARTED ON RWY 6 AT BHM. THE MSA AT BHM IS 3700 FT MSL AND THE OBSTACLE CLRNC DEP FOR THIS RWY IS TO CLB TO 1700 FT MSL PRIOR TO TURNING ON COURSE. THE CLRNC ISSUED TO US BY BHM CLRNC DELIVERY WAS AS FOLLOWS: ACR X FLT ABC CLRED TO JACKSON VIA RADAR VECTORS TO MEI THEN AS FILED. CLB RWY HDG TO 5000 FT; EXPECT FL280 IN 10 MINS; CONTACT DEP CTL ON FREQ 123.8 AND SQUAWK ABCD. THE TWR INITIALLY CLRED US INTO POS TO HOLD FOR A KING AIR WHICH HAD JUST BEEN GIVEN TKOF CLRNC. (WE THINK THAT THERE WAS SOME CONFUSION IN THE TWR BTWN US AND THIS ACFT DURING THE EVENTS THAT OCCURRED ON DEP.) WHEN THE TWR SUBSEQUENTLY ISSUED US TKOF CLRNC; THEY INSTRUCTED US TO MAINTAIN 2500 FT ON DEP. THIS CLRNC WAS READ BACK AND UNDERSTOOD BY ALL 3 CREW MEMBERS. THIS CLRNC WAS GIVEN TO US BY A FEMALE CTLR. (GENDER IS ONLY REFED HERE TO DIFFERENTIATE HER FROM THE CTLR WHO LATER TOOK CTL OF OUR FLT.) JUST AFTER TKOF; AT ABOUT 700 FT AGL; A MALE CTLR ABRUPTLY CAME ON THE RADIO AND SAID; 'ACR X FLT ABC; START YOUR TURN.' I QUESTIONED THIS AND HE SAID; 'YOUR TURN TO 140 DEG HDG WHICH WE ASSIGNED YOU AND YOU ACKNOWLEDGED.' NONE OF THE 3 CREW MEMBERS ON BOARD HEARD ANY INSTRUCTION TO TURN TO 140 DEG HDG ON DEP. HE THEN ABRUPTLY SWITCHED US TO DEP CTL. THIS TWR CTLR SEEMED TO BE MORE INTERESTED IN SCOLDING US FOR WHAT HE THOUGHT WAS OUR MISTAKE THAN CLRING UP THE CONFUSION WHICH WAS NOW AFFECTING THE SAFETY OF FLT. WHEN WE CONTACTED DEP CTL; THEY ASSIGNED US 5000 FT MSL AND SUGGESTED THAT WE TURN IMMEDIATELY TO A HDG OF 250 DEGS TO AVOID WX. WE FEEL THAT THE TWR CTLR WHO TOOK CTL OF OUR FLT FROM THE FEMALE CTLR MAY HAVE CONFUSED US WITH THE KING AIR WHO DEPARTED AHEAD OF US. HIS INSTRUCTIONS TO TURN TO A 140 DEG HDG WERE IN CONFLICT WITH THE OBSTACLE CLRNC PROC FOR RWY 6 WHICH REQUIRES RWY HDG TO 1700 FT MSL PRIOR TO TURNING. ALSO; HOLDING US TO 2500 FT MSL IN THIS TURN DID NOT MAKE SENSE WITH THE MSA AT 3700 FT MSL WHEN HIS TURN VECTORED US INTO THE AREA OF THE HIGHEST TERRAIN.