Abstract :
Water tank pressurization system is a system used in potable water systems as a source
of water supply power, regulating the amount of air pressure entering the water tank and
preventing unwanted contamination from entering through the air. Compressed air comes from
2 sources, namely the pneumatic system and the air compressor. The pneumatic system supplies
compressed air from 3 sources, namely APU, engine bleed air and ground connection.
This study aims to determine the cause of galleys and lavatory experiencing low water
pressure in hangar 4 PT. GMF Aero Asia. The method used in this research is Fault Tree
Analysis (FTA) to find the root cause of the possibility that will occur in the problem of pressure
loss in the water tank pressurization system on the Boeing 737-800 NG aircraft.
In the process of inspecting the water tank pressurization component according to the
FIM, there were 3 failures, namely in the fill/overflow valve test water seepage was found in
the drain hose, the air filter element at the air compressor inlet was dirty so that it obstructed
the air supply, and a failure in the check valve located on the air compressor line. causes the
water tank to lose the air pressure needed to drain the water. The three damaged components
must be replaced because they cannot be repaired. From the results of the FTA, it can be
concluded that there are 13 basic events that can trigger the top event.