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Loss of Automatic Pressurization Control

G500 Emergency Procedures

This is a work in progress


AFM Procedure

[AFM, §04-21-40]

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System Impacts

  • Landing Field Elevation (LFE): Limited to less than 10,000 MSL with the CPCS in Semi Mode.

Corrective Action

  1. CPC FAULT/MANUAL Switch . . . MANUAL

  2. NOTE

    When operating in MANUAL mode, the cabin rate of change should be monitored to maintain a maximum of ±500 FPM. Changes in engine thrust will affect cabin airflow and cause variations in cabin pressure and rates of change.

  3. CABIN ALT Knob . . . Control to ±500 FPM rate of change

  4. CPC FAULT/MANUAL Switch . . . Deselect MANUAL

  5. CPCS (OHPTS / CPCS / System Mode) . . . SEMI

  6. CPCS SEMI (TSC / SYSTEMS / CPCS) . . . Set values (as required)

  7. If semi-automatic pressurization control is not regained:

    1. CPC FAULT / MANUAL Switch . . . MANUAL

    2. CAUTION

      WHEN OPERATING IN MANUAL MODE, MONITOR CABIN ALTITUDE CLOSELY, ESPECIALLY IN DESCENT, TO ENSURE THAT CABIN ALTITUDE DOES NOT DECREASE TO LESS THAN LANDING FIELD ELEVATION, CARE MUST BE TAKEN TO LAND UNPRESSURIZED WITH OUTFLOW VALVE IN FULL OPEN POSITION.

      CAUTION

      CLOSELY MONITOR CABIN DIFFERENTIAL PRESSURE. DO NOT ALLOW DIFFERENTIAL PRESSURE TO EXCEED 10.80 PSID.

    3. CABIN ALT Knob . . . Control to ±500 FPM rate of change

  8. If manual pressurization control is not successful:

    1. Crew Oxygen Masks . . . Don

    2. COMM JACKS . . . MASK

    3. RAM AIR (OHPTS / ECS) . . . Select

    4. CPC FAULT / MANUAL Switch . . . MANUAL

    5. NOTE

      Continued flight with the TROV full open prevents cabin overheat conditions.

    6. CABIN ALT Knob . . . Climb (Full Open)

    7. Altitude. . . Descend to 10,000 feet (or less)

    8. Passenger OXYGEN . . . MAN

  9. Upon reaching a safe altitude, attempt to regain control of the pressurization system as follows:

  10. NOTE

    Avoid excessive throttle movements while trying to regain control of the pressurization system.

    1. a. RAM AIR (OHPTS / ECS) . . . OFF

    2. AUTO or MANUAL CPCS Control . . . Try to restore

References

Gulfstream GVII-G500 Airplane Flight Manual, Revision 1, August 31, 2018

Gulstream GVII-G500 Production Aircraft Systems, Revision 1, Oct 1, 2018

Revision: 20190516
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