In the absence of a QRH or FCOM here, I'm just wondering in what circumstances you would not want to turn on the yellow AC Pump (assuming fluid present) in the event that the APU generator was available? That Yellow-SYS pressure from the windmilling No. 2 engine ED Pump will decline as soon as you slow down for the approach.
Can you guys confirm that it is still policy to make one attempt at an APU start in the Dual-ENGINES failure case?