many of you make one big mistake in this discussion :
the pilots after departure in new york surely DID NOT KNEW that the gear is completely failed !
In a todays interviews in the radio and on tv, the capitan said:
1. 30 mins into the flight they got information about fluid loss in central hydraulic sys.
2. They separated the centr hydraulic system, switched off the pumps "to have the rest of the systems safe".
3. They new that they would have to use alternate gear extension method at the arrival.
It was said in two different interviews.
Luckily, at least the alternate flaps extension mechanism worked.