601.When is the muting circuit operative?

60.When does the vacuum generator operate ?

59.How is the waste transported to the waste holding tank ?

58.Where does the toilet bowl rinsing water come from ?

57.After flushing at low altitude :

56.What happens when the flush switch is pressed at high altitude ?

55.On ground, when does the vacuum generator start to operate ?

54.Why are drain valve installed in the waste water drain system ?

53.How many potable water quantity indicators are there ?

52.Where is the main drain port of the potable water system ?

51.How many potable water service and drain panels are fitted to the aircraft ?