A320 Yellow Hydraulic Level in Cruise

[pproonhero]

Something I have been wondering for a while, without being able to find a decent explanation, why, during the cruise, does the yellow hydraulic level always show above the normal fill range?

[rudderrudderrat]

Hi pproonhero,
Some of the Y Hyds were hiding in the extended cargo door jacks on the ground. When the doors are closed, the contents gauges show an increase.

[pproonhero]

Thank you rudderrudderrat.

[Tally-ho1]

...and in cruise the green hyd syst goes the other way...we'll see a decrease in filling range, due gear uplock.

Tally-Ho

[Cough]

Guess mode...

On ground, all flight controls droop with gravity (mainly Ailerons and elevator). When the pcu's pressurise and the jacks return the their correct position, the hyd system levels will change as a result - This might be the yellow system increase we see...

...Guess mode back off...