A320
Confusion; Distraction; Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Equipment Problem Dissipated; Flight Crew Became Reoriented
Human Factors; Procedure
We were prepared for a departure from SFO on Runway 28L. As we were holding short of 28L we were given clearance to cross 28L and line up on Runway 28R. The First Officer put in the changes to the box and briefed me on the new V-speeds. They were roughly the same as the numbers for 28L and I specifically remember that V2 was 140 KTS. As we turned onto 28R I looked down at my PFD and saw V-speeds. I also asked him if he was ready and he said yes. When we were cleared for takeoff; I advanced the throttles to the MAN/FLEX detent. As we began rolling; we got a Master Caution with a 'ding.' I assumed that the flex number had dropped out of the FMC so I advanced the throttles to TOGA to continue the takeoff. We were light and there was quite a bit of wind so the airspeed jumped up and we accelerated very quickly. I was waiting for the V1 call when the First Officer announced that we had no V-speeds displayed on the PFD. At that point we were approaching 160 KTS which I knew was well above V2. I felt it was safe to continue the takeoff and that it was a better decision than to abort at a speed well above V1. I believe that the First Officer changed the runway correctly prior to entering 28L but either hit the wrong button or didn't push hard enough for the runway insertion to take. As we started the takeoff I believe he inserted the change and that's when the speeds dropped off the airspeed tape. By that time I was completely outside and the 'ding' distracted me from my FMA check. I just went to TOGA and thought everything was normal except for the lack of a flex temp.
When an A320's throttles were set to MAN/FLEX; a Master Caution and 'DING' alerted but the Captain continued the takeoff after the FMC dropped the V speeds because the First Officer did not fully finish the runway change input from SFO 28L to 28R.