Medium Transport; Low Wing; 2 Turbojet Eng
Troubleshooting; Time Pressure; Distraction; Communication Breakdown; Confusion
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance
Chart Or Publication; Procedure
[The] flight was operating late due to a last minute plane swap in CLT.  The crew was made aware of after deplaning and some members going to get food for dinner break.  We were swapped into an aircraft with maintenance issues further adding to our delay.  We ended up with deferred APU and departed for [the destination].  As we got to the end of runway 36C we had a 'OB GRND SPLR FAIL' status message appear.  We moved off taxi way E to E2 to hold short runway 36C while I contacted maintenance via the radio.  They advised us on what to do and the fault cleared.  Tower asked if we could take an E2 departure and I declined as we had not requested those performance numbers.  When cleared for takeoff we were told.  '[callsign] cleared to back taxi runway 36c; fly runway heading cleared to take off runway 36c'  in one radio transmission.  The first officer repeated this clearance and we took off.  The departure plate reads 1;276 feet turn to heading 330 UNLESS advised otherwise by ATC.  We were advised runway heading.  CLT tower questioned our course at about 2;000 feet and I replied 'You (tower) gave us runway heading.'  The tower controller replied back that the SID requires a turn to heading 330.  I left it alone and we were given further vectors to on course.  No other issues occurred.  There was a radio issue on the hand off to departure but unsure what happened there.The takeoff clearance was given clearly.  ATC needs to be aware of what our departure plates read and how to better issue a clearance in accordance to it.  I.e..... turn to heading 330..... comply with the SID...... depart via the SID..... takeoff via the SID.....
A flight crew reported a deviation from a departure clearance due to a communication issue with ATC.