SMA PLT FLIES WRONG HDG ON SID. TRANSPOSES NUMBERS. HDG DEV.

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FOR A FLT FROM SUS TO CWA MY CLRNC WAS VIA THE CARDS 1 SID; CAPITAL TRANSITION THEN AS FILED. THE SID PROVIDES FOR RADAR VECTORS TO THE STL VOR THEN V-9 TO THE CAP VOR. THE ON COURSE HDG TO STL FROM SUS IS 031 DEG. MY RELEASE WAS AFTER TKOF TURN R TO 310 DEGS. UPON TKOF I TURNED R TO A HDG OF 031 DEGS; WHICH IS WHAT I EXPECT AS THE ON COURSE HDG TO STL. EXPECTING 031 DEGS I MENTALLY TRANSPOSED 310 DEGS. AFTER HDOF FROM SUS TWR TO STL DEP I WAS TOLD TO FLY 310 DEGS AND CLB TO 4000 FT. I ONCE AGAIN TRANSPOSED 310 DEGS FOR 031 DEGS. STL DEP THEN ASKED TO CONFIRM I WAS FLYING 310 DEGS. I THEN REALIZED MY ERROR AND SAID NEGATIVE WHAT HDG TO YOU WANT ME ON. STL SAID FLY 280 DEGS AND DO NOT CLB ABOVE 2500 FT. WHAT WOULD HAVE PREVENTED THIS? PLT SHOULD NOT ANTICIPATE HDGS ATC WILL ASSIGN BEFOREHAND. ATC SHOULD NOT ASSIGN HDGS WHICH CAN EASILY BE MISUNDERSTOOD OR TRANSPOSED FOR DIRECT ON COURSE HDGS WHICH THE PLT WOULD WANT TO FLY. FINALLY SIDS SHOULD NOT CONTAIN RADAR VECTORS BUT SHOULD ALWAYS GIVE SPECIFIC HDGS TO BE FLOWN.