Originally Posted by
NSEU
Is it normal procedure for the crew to attempt a normal extension first, then use alternate extension for the remaining unextended gear?
The procedure for a loss of #4 hydraulic system is to extend all Landing Gear using the alternate gear extension system. That means that the Nose and Body gear are extended using the alternate system(separate switch) even though they still have normal hydraulic pressure.
For both actions in the checklist, there is a note saying "Action is irreversible". But is it really irreversible for the system with the functioning hydraulic system(which in this case was the gear that worked properly). After all, the hydraulics for that system are still working.