أخي الكريم فهد المخطط المرفق يوضح حالة خاصة وهي ما تعرف بـــــ INNER CELL FULL LEVEL
When the Inner Cell Full Level is reached, the center tank ***** are signalled to stop & the Inner Cell ***** then supply the engines until the full level reaches the underfull level
أما حالة الـــــ UNDERFULL LEVEL
When fuel level in the wing tank Inner Cell drops to the Undefull Sensors, they signald the center tank ***** to restart, provided fuel is in center tank
((The difference between the full level & the underfull level is 500kg))
وهنا نرجع الي أجابة السؤال ولنقل الـــــ inner cell underfull level حتي يتم التوضيح أكتر
When the center tank ***** are selected ON, the related ***** are running on ground when slats are at 0 degrees
With the slats extended, the AUTO CTL relay are energized & the center tank ***** stop
On engine start, the AUTO CTL relays are de-energized to permit center tank ***** to run for 2 minutes to scavenge any water that may be in the center tank prior to take-off
After 2 minutes the time delay relay & the center tank ***** AUTO CTL relays are energized to stop the *****
With the slats retracted, the contacts are open to de-energize the AUTO CTL relays, Center tank ***** will run until signalled to stop by the low level sensors & the 5 minutes time delay relays