P-3 Pressurization

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  1. Master PRESS SYSTEM light on
    • Locate fault on overhead panel. Secure faulty system. Reset for continued warning protection
    • R REFR OVHT - 166 C
    • O EDC Low Oil Pressure (50 psi)
    • O EDC High Oil Temperature - >121 C, low level, high
    • engine temp
    • F FAN OUT light - fan inop or lack of airflow
  2. REFR OVHT light
    • flight: Dump EDC. After light is out, operation is permitted in the two-dot position or warmer.
    • Deck: Turn off GRN AIR COND switch, after light is out, operation is permitted in the two dot position or warmer;
    • (C) check L + R Heat Exchanger Blower CBs (B/MEDC).
    • System: On ground, the Overtemp lockout relay will Dump EDC or Air Multiplier Valve closes, ground air switch stays on and the blower fans continue to run.
    • With electrical power available:
    • *1. AUX VENT switch - OPEN
    • *2. Outflow valve switch - OPEN
    • *3. EDCs - DUMP
    • *4. AUX VENT switch - Close at 1 inch differential
    • Without electrical power available:
    • (T) depressurize pneumatically
    • *5. Free-fall chute - OPEN
    • If cabin altitude exceeds 10,000ft, the flight station shall:
    • *1. Don smoke masks.
    • *2. Alert crew.
    • Regardless of cabin altitude, continue with the following steps:
    • 3. Verify obstacle clearance.
    • 4. Investigate pressurization loss.
    • Other crewmembers should:
    • Verify condition of flight station personnel, provide assistance to other personnel as required, be prepared to set Condition V
    • Check EDC Spread - if none - check that AUX VENT Switch wasn't hit. o/wise rapid Decompression procedures.
    • Autopilot - not engage then scissors switch problem verified
    • Check cabin altitude and cabin differential.
    • Check EDC spread - if none perform Rapid Decompression proc
    • Check Ground Air Switch - Perform Rapid Decompression proc
    • Check Differential - if slight, aux vent may be stuck open:
    • Check Aux Vent CB
    • If no differential - check Outflow valve switch
    • Check Aux vent CB (MEAC/MEDC)
    • Outflow Valve CB (FEAC)
    • Attempt to close Outflow valve manually.
    • Check for holes:
    • Overwing hatch
    • Free fall chute
    • pyrotechnic pistol port
    • bomb bay access panel
    • HSC outer door
    • Do PRESSURIZATION LOSS procedures.
    • Try to ascertain the cause of the trouble and, if it cannot be fixed in flight, he should decide immediately whether to continue the mission or to descend to a safe altitude.
    • Indication: goes to outside pressure in less than one second
    • fog not to be confused with smoke
    • rush of air from lungs, momentary dazed sensation, gas pains, hypoxia if O2 not immediately available.
    • Investigate: Overwing Hatch, Main Cabin Door, HSC, Structural failure.
    • EDC dump, loss of autopilot, other indications of scissors switch
    • Do PRESSURIZATION LOSS procedures first
    • 1. Pressurization ground check switch - Test
    • 2. Ground air-conditioning switch - ON
    • Note: Manual modulation of outflow valve may be required initially to minimize cycling.
    • (T) Have FE open outflow valve completely prior to AC switch and then close in small steps to regain pressurization
    • 3. Ground air sensing CB - PULL (MDC) MLC 1Upper
    • 4. Pressurization ground check switch - NORMAL
    • Caution: ...the ground air sensing CB should be reset after landing rollout.
    • (T) Refer fans are not running!
  9. RAPID D systems
    • TEST position - allows Aux vent and outflow valves to go to position selected (Closed and Auto)
    • Ground AC - EDCs undump, refer fans run, Aux vent closes
    • Pull the gnd air sensing CB - Fans stop, regain control of aux vent, normal icing system (Prop and EMP)
    • Reset on runway - refer fans are not running Icing systems back to ground operation.
    • AUX VENT switch to open immediately
    • Warn: Take action ASAP, rapid descents may injure personnel
    • (C) Broken control press line, frozen line, leak, reference port blocked (port above copilot's window)
    • May attempt to control pressure manually:
    • Open Outflow valve
    • Aux Vent Switch back to closed
    • Go from OFF to Open back to OFF in quick bursts - watch cabin rate of climb
  11. ONE EDC INOPERATIVE (AC System Malfunction in Flight) and cabin exhaust fan is operable
    • reduce cabin electrical load to only that used for navigation should the cabin temperature rise excessively.
    • Note: Climbing to altitude or opening equipment doors will decrease the efficiency of the air-conditioning system.
  12. LOSS of Ground AC without Annunciator lights
    • Indication: No cold air coming out of AC.
    • Ground AC switch - OFF and then back ON.
    • IF ground AC does not come back on, power to air multiplier valve may be off.
    • Check Air Multiplier Valve CB - MEDC
    • (C) Air multiplier inlet pressure or outlet temperature sensor closed air multiplier valve and secured the ground AC
    • Refer fans continue to run and the switch stays on - I think.
  13. FAN OUT light
    • (T) Cabin Exhaust Fan switch - ON
    • (T) Check Fan CBs (B/EMDC)
    • (T) Check to see if fan is running
    • (T) Consider airflow - weak EDCs at altitude
    • If fan inop - execute NATOPS:
    • Open equipment doors for additional cooling
    • Use minimum electrical equipment
    • IF both EDCs are inoperative, Open AUX VENT
  14. EDC PRESS LOW (<50 psi oil pressure)
    • Check loss of spread (driveshaft) If so, Disconnect and Dump.
    • If spread is indicated:
    • (T) Consider altitude and condition of other EDC, dump to see if lose pressurization, may consider dump and descend (check MOSA)
    • Disconnect, check for loss of spread and Dump.
    • (T) If spread remains - check EDC disconnect CB (MEDC) and
    • EDC inlet and discharge indicator CB (INST 1 or 2)
    • Perform Emergency Shutdown checklist
    • (T) Pull engine to flight idle and call for E-handle
    • Caution: Dump if continued operation due to greater emergency
    • (T) Look for signs of oil loss, post observer on engine
  15. EDC TEMP HIGH (>121 C)
    • Check engine oil temperature - if high correct. (T) Cool to 60 C
    • (T) Consider altitude, condition of other EDC (can dump and see if pressurization holds), consider dump and descend prior to disconnect
    • If unable to control, disconnect, monitor for loss of spread, dump.
    • If loss of spread is not indicated after disconnect
    • (T) Check EDC Disconnect CB (MEDC) and Indicator (INST1,2)
    • execute Emergency Shutdown Procedure.
    • If engine is allowed to operate due to greater emergency, the EDC should be dumped.
    • (T) Lights check
    • (T) Temperature (hotter) and/or Pressurization (less differential) can verify indication - not a gauge failure.
    • EDC should be Disconnected and Dumped.
    • If EDC fails to disconnect, as indicated by EDC press low light remaining off, the respective engine should be secured.
    • (T) Check EDC Disconnect CB - MEDC.
    • If the engine is allowed to operate due to a greater emergency, the EDC should be dumped.
    • Refer to AC System Malfunction (loss of one EDC)
  17. CABIN PRESS light
    • Do Pressurization Loss procedures
    • Light on at cabin altitude 10,000 +- 500ft. Light out by 8,000ft on descent.
    • (T) Careful reading the cabin altitude indicator, small needle indicates when over 10,000ft.
    • When in doubt, go on O2
    • (T) Full Forward and to the right
    • Altitude - not above 12,000ft
    • CABIN ALT - 10,000ft
    • BAR CORR - 28"
    • Dump the nose and drop the gear, Vne or 300KIAS
    • A Autopilot - Disengaged
    • P Power Levers - Flight Idle
    • L Landing Gear - Down
    • A Airspeed - Vne to FL245 then 300KIAS
    • P Pressurization - As Required
    • GEAR Don't forget to raise the gear, and wait for 190 KIAS!!
    • 1. Close Cabin door and hatches
    • 2. Open doors on avionics racks involved
    • 3. Keep cabin exhaust fan running.
    • If cabin temp exceeds 27 C, selected avionics should be turned off to avoid reduction in reliability and operational readiness.
  21. Master RACK OVHT light
    • Alert the crew, activate the firebill
    • Fire of Unknown Origin checklist
    • Let the crew know we have a Rack Ovht light
    • Locate overheated bay(s) by illuminated individual bay light(s).
    • (T) reset bay to reset flight station light. Announce light out.
    • Provide required cooling or secure equipment as necessary.
    • Come on with MDC failure.
    • The AMH-33 (Digital Magnetic Tape System) will cause the rack overheat indication when the system is initially turned on, or will illuminate continuously when a loss of airflow is detected.
Card Set
P-3 Pressurization
P-3 Pressurization
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