Citation X (C750)
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert
Human Factors
Departed SFO on the Offshore 5 departure. We were vectored off departure; then vectored and given a 210 heading to rejoin the departure. Because the course needed to be defined with a VOR that was not depicted on the FMS Flight Plan Page (PYE VOR); I opted to step down the automation and type PYE into my green needles and join the appropriate radial. I was not aware I must have hit the chart number at the bottom of the iPad with my hand or arm; and switched from the OFFSH5 TO THE PORTE3 departure. In short; I was now looking at the Porte 3 departure; which is a VERY similar visual depiction. The radial off PYE was 135 on the Porte 3; but 151 on the Offshore 5. We were turning from the 210 heading to join the 135; and never did intercept the 151. I noticed our mistake within a couple of minutes; but by the time we were correcting we were given direct to another fix. I noticed the wrong departure on the iPad. We must be very aware that the iPad can change pages without the pilot knowing. I had a similar experience when the iPad was brand new. That one was a wrong ILS frequency for the parallel runway-- another almost identical visual depiction on the chart. We caught that one on the approach brief and I learned that you can lock the screen from changing while SWIPING the screen. I know of NO way to lock it from changing when the numbers at the bottom are accidentally bumped with a body part.
CE750 Captain reports being vectored to a 210 heading then instructed to rejoin the OFFSH5 departure from SFO. Using the PYE VOR and the required radial with green needles is deemed the best method of doing so; but the iPad chart display is apparently bumped bring up the PORTE3 and the 135 Radial is intercepted instead of the 151 Radial.