B737-700
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 409
Workload; Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Human Factors; Procedure
Flying the OHSEA 1 Arrival into SNA. The RNAV (RNP) Z Runway 20R was loaded into FMC. We were told to expect the RNAV (GPS) Y Runway 20R. At two-miles from KLEVR I programmed the FMC with the new approach. Then as I was cleaning up the LEGS page; the LNAV disconnect flashed in the scratch pad momentarily and the aircraft went straight instead of making the turn at KLEVR. We corrected the turn to get back on course. ATC asked our heading and we told them what happened. He gave us a heading and said no problem. He vectored us to final and we landed uneventfully.
B737-700 Captain reported a track deviation resulted when the flight crew tried to reprogram the FMC following a late clearance change from ATC.