Regional Jet 900 (CRJ900)
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Situational Awareness; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Aircraft; Human Factors
In line for 26L PENCL2; cleared to back taxi for 8R departure. FMS was updated; and runway change items were checked. HDG bug not updated. ATC asked for updated first fix of RONNI; FMS verified programmed correctly. Cleared for takeoff 8R first fix of RONNI. Normal call outs of '8R set thrust.' As I checked thrust set and [runway] heading realized 275 was selected. Tried to sync heading to runway but button was stuck and unresponsive. Continued takeoff. After pulling gear up and activating speed mode and NAV mode I started manually spinning heading bug back to a 095 heading. While climbing we encountered wake from previous departure as the flight director started a turn to the south which was quickly noticed and corrected. We had been on a southeasterly heading for probably less than 30 seconds. FMS mode was active shortly after and we continued to RONNI. ATC queried our heading which was now on the correct heading toward RONNI. Last minute runway change; FMS updating; and runway change items that are required. The updating of heading bug was not caught in checklists or scans. That coupled with a stuck heading sync button made it difficult to correct the mistake quickly.
CRJ-900 First Officer reported a track deviation and wake encounter occurred departing ATL following a last minute departure runway change.