That is EXACTLY why you do the initial short test. You should see NO pressure drop.
According our FCOM a drop up to 100psi is acceptable....
Actually the nominal pressure in the oxygen system is 1800 psi.The low limit for despatch from base after a daily check is 1700 psi. It looks like you have a leak.
The lower limit for dispatch differs in our company per stretch. For example over the Himalaya we need to have 1650 psi, and from another station back to homebase 700psi is acceptable. On what do you base there is a leak? In case of a leak, the pressure should always drop, also when not using any masks...
The lowest our table -the company put one in our QRH- goes is 8000ft; but there 1500psi should give you 5:50 manhours of 100% oxygen on the 744F. I suppose the flightdeck system is similar to the pax -400.
No, the freighter has more bottles for cockpit and supernumary crew. The Pax version only has 1 cockpit bottle...
However i like to see your tables...
Depends on the flt and routing, LH, ULH over mountains or over the Atlantic, you can dispatch with 680 psi.
Like we do....