AS Chpt 13

• Intro to water & waste management system:

  • Portable water is water that is fit for drinking
  • Gray water is any water that has been used
• The potable water system has these subsystems:

  • Storage and distribution 
  • Water quantity indication 
  • Water heating
• The waste disposal system has the following subsystems:

  • Gray water drain system 
  • Vacuum waste system
• Water storage & distribution:

  • The water storage and distribution system supplies potable water to the lavatories and galleys
• Water tank:

  • Supply water to the gallery & lavatories
  • 3 water tanks that contain portable water
  • They are pressurised to about 40 psi by compressed air from compressor or engine bleed air
• Aft potable water service panel & preselect overflow valve:

  • The tanks can be filled from the aft potable water service panel & preselect overflow valve to fill the water tanks
• Preselected overflow valve:

  • To fill the water tanks
• Overhead water distribution line:

  • Supplies water to the lavatories & galleys
• Isolation/drain valve:

  • It is placed at the forward & aft part of the system
  • These 2 valves allow to isolate parts of the system
  • Allows to drain the forward part of the system to the forward drain valve
• Water supply shutoff valve:

  • There is a water supply shutoff valve in each lavatory & galley

  (Note: water heater ensure warm water is available to lavatories)
• Drain valve:

  • There is a drain valve in each lavatory
  • It lets water drain from the distribution lines in the lavatory
• Galley faucet drains:

  • The galley faucet drains the galley distribution lines
• Forward system drain:

  • drain water from the distribution system
• Aft system drain:

  • Drain water from the distribution system
• Tank drain:

  • Drain water from the water tank
• Filling the Water Storage Tanks:

  1. Connect water supply hose to the service port
  2. Turn the tank fill valve handle to fill
• The preselect/fill overflow valve has these functions:

  1. Water flows into the potable water tanks
  2. The air in the water tanks vents overboard as water flows into the tank.
  3. Closes when the water tanks fill to the selected water level.
  4. Water flows overboard during the filling procedure when the tanks are overfilled.
  5. Air supply to the water tank is switched off
• Water Quantity Indication:

  It uses the water quantity transmitter in the water tank to indicate the water quantity on the aft potable service water panel or cabin system control panel (CSCP) and the cabin area control panels (CACPs)
• Gray Water Drain System:

  The gray water drain system permits waste water from the lavatory and galley sinks to drain overboard
• Waste water dumped overboard:

  • Waste water from the sinks goes through lines & flows overboard through the forward or aft drain mast on the bottom of the airplane
• Pressure switch:

  • When the pressure in the drain line increases beyond a limit, the pressure switch opens
  • This de-energises the motor & the valves opens to remove any blockage in the line
• Restricted valve:

  • A grey water drain restrictor valve keeps the amount of air flows out of the plane to a limit when the airplane is in the air
  • This helps to decrease noise in the lavatories & galleys
• B777 vacuum waste system:

  • Removes waste from the toilets and stores it in the waste tanks. The waste stays in the waste tanks until they are serviced
  • Waste collects in the toilet. Suction then moves the waste to the waste tanks. The suction is made by the vacuum blower
• B777 vacuum waste system:

  • The difference between the cabin pressure and the outside pressure also moves the waste to the waste tanks
  • Remove the waste in the waste tanks through the waste service panel
• Waste tank:

  • Waste tanks collect waste from the toilets
  • There are 3 waste tanks on the airplane
  • The forward & mid tanks can hold 314L of waste each & the aft tank can hold 239L of waste
• Continuous level sensor:

  • They are in the tank drain lines & it calculates the amount of waste in the tanks
  • This data is only for indications that show on the cabin area control panels (CACP) & cabin system control panels (CSCP)
  • It is a capacitance-type pressure sensor
  • Wires connect the electrical connector to the logic control module (LCM)
• Continuous Level Sensor:

  • The remote diaphragm and the capillary tube find the pressure of the air in the tank
  • The sensor finds the difference between the air pressure in the tank and the liquid in the drain line
  • It uses the difference to calculate the amount of waste in the tanks
• Point level sensor:

  • The waste tank quantity indication system consists of the point level sensors, the continuous level sensors, & logic control modules (LCMs)
  • It is attached to the upper part of the tanks
  • The waste tank point level sensor sends a signal to the LCM when the waste tank is full
  • There are 6 waste tank point level sensors, 2 on each waste tank
  • The sensor is a capacitance type sensor
• CSCP/CACP Indications:

  The cabin system control panel (CSCP) or cabin area control panels (CACP) controls and monitors the lavatory functions and waste tank levels respectively
• Lavatory waste tank status:

  • The lavatory waste tank status screen monitor the conditions of the lavatories & waste tanks
• Lavatory inoperable control screen:

  • Show the conditions & status of each lavatories
  • This is represented by OP or INOP to show that lavatory operational or inoperative
• Waste tank full:

  • INOP indicates automatically for all lavatories with the same waste tank if the waste tank is full (FULL TANK)
• Waste tank rinse fitting assembly:

  • Supplies routing for supply water to rinse the waste tanks
• Waste tank rinse filter:

  • Removes small particles as the rinse water goes through it
• Waste tank rinse nozzle:

  • Points rinse water at the point level sensor & the waste tank interior surface
  • Removes waste materials from the point level sensor
  • Supplies pre-charge into the waste tanks
• Waste tank ball-valve:

  • Waste tank ball-valve & control cable permit the waste tank to drain
• T-handle:

  • A T-handle attaches to 1 end of the control cable
  • The other end attaches to the actuation lever which opens & closes the drain ball-valve
  • The limit switch stops the operation of the vacuum blower when the valve is not closed
• Toilet rinse water:

  • The vacuum blower supplies suction for the waste system to remove waste
  • The suction moves the toilet rinse water & its contents to the waste tank
• Liquid separator:

  • Removes moisture & waste particles from the waste tank air before venting the air overboard
  • The air goes in a circular path when air goes into the separator
  • Centrifugal force removes moisture from the air
  • The moisture drains out the bottom of the liquid separator
  • The air then goes to the overboard vent line
• Vacuum blowers:

  • Operates if the airplane is below 16000 ft when the flush switch is selected
  • It causes a pressure difference large enough to move the waste from the lavatories to the waste tanks
  • The filter removes particles from the air that cools the blower motor