747-400 loses all 4 Generators

Another consideration.... With Standby Power you still have the IRU's running, providing you with position and heading information (which will feed the Captain's MAP display) and attitude and heading information (which will be provided to the PFD). The IRU's are powered by the APU Battery in the absence of main bus AC. If you were able to crank the APU starter motor (by pulling certain Air/Ground CB's), there would be an enormous drain on the APU Battery during start. How this would affect the IRS's I really can't say. If you got main bus power online, but have lost the IRU's, it's a big sacrifice. IRU attitude can be recovered with the aircraft in motion, but not position.You might be able to get both GPS's to operate with main bus power re-established, however, this probably won't be able to supply position to the MAP display with the IRU's inop. Some 744's have Multi-Mode Receivers which include GPS as well as ILS/Marker. One GPS system may even be operative under Stby Power ops, but it will only last as long as the batteries do.A complex issue indeed.Cheers.Q>