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Dual Generator Failure (Below 37,000 Feet)

G500 Emergency Procedures

This is a work in progress


AFM Procedure

[AFM, §04-04-20]

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System Impacts

  • Autobrakes: Disarmed.
  • Main AC Bus: Loss of items powered by respective Main AC Bus.

Corrective Action

    WARNING

    FULLY CHARGED MAIN BATTERIES WILL PROVIDE APPROXIMATELY 10 MINUTES OF ELECTRICAL POWER AFTER TWO APU START ATTEMPTS. THE EBHA AND UPS BATTERIES WILL PROVIDE APPROXIMATELY 30 MINUTES OF ELECTRICAL POWER.

  1. FUEL CROSSFLOW . . . OPEN
  2. MAIN FUEL PUMPS (Left and Right) . . . Verify On
  3. ALT FUEL PUMPS (Left and Right) . . . Verify Off
  4. GEN (Left and Right) . . . Both OFF wait 5 sec, then Both ON
  5. AC / DC RESET Switch (Lighted or Unlighted) . . . PRESS and RELEASE
  6. If AC power is restored:
  7. NOTE

    The temporary loss of AC electrical power will cause the horizontal stabilizer to fail resulting in the FCS using elevator for pitch trim. After AC power is restored, a FLT CTRL RESET will return normal horizontal stabilizer operation.

    1. AP . . . DISCONNECT
    2. FLT CTRL RESET . . . PRESS and RELEASE
    3. CAUTION

      CONFIGURE ELECTRICAL SYSTEM TO STAY AT OR UNDER A 100% LOAD ON AC / DC POWER SYSTEMS.

    4. Airplane . . . Return to normal configuration
    5. Procedure complete.
  8. 7. If AC power is not restored:
  9. CAUTION

    LAND AS SOON AS POSSIBLE WHEN ANY ELECTRICAL CONDITION REQUIRES OPERATION ON MAIN BATTERIES ONLY.

    A MAXIMUM OF TWO 30-SECOND APU START ATTEMPTS MAY BE PERFORMED.

    1. APU MASTER . . . ON
    2. NOTE

      The APU READY light may not illuminate if the APU oil temperature is below the minimum required for start. The APU start is not inhibited and may be attempted.

    3. APU . . . START
    4. APU GEN . . . Verify On
    5. If the APU fails to start, or if the APU GEN is inoperative:
    6. (1) Go to Step 8.

    7. Once the APU generator is operating:
    8. (1) MAIN FUEL PUMP and ALT FUEL PUMP (Left and Right) . . . ON

      (2) APU Generator Load . . . Check

      (3) If the APU Generator load is greater than 78%, and flight above 35,000 feet is required:

      (a) Refer to 03-04-70, Electric Load Shedding.

      (4) If the APU Generator load is less than 78%:

      (a) FUEL CROSSFLOW . . . CLOSE

      (b) AP . . . DISCONNECT

      (c) FLT CTRL RESET . . . PRESS and RELEASE

      (d) Airplane . . . Land at nearest suitable airport

      (e) Procedure complete.

  10. If the APU fails to start, or if the APU GEN is inoperative:
    1. RAT . . . Deploy
    2. NOTE

      The RAT will power the emergency AC, L ESS DC / R ESS DC busses.

      To ensure proper RAT operation, do not reduce airspeed below 200 KCAS.

    3. RAT GEN . . . Verify On
    4. EMERGENCY POWER . . . ARM
    5. AP . . . DISCONNECT
    6. FLT CTRL RESET . . . PRESS and RELEASE
    7. RAT GEN Load . . . Monitor
    8. If the RAT Gen Overload (caution) CAS message is displayed, perform the following, pausing between actions to observe if the CAS message clears:
    9. (1) TAT Probe 1 SSPC 3423 PULL

      NOTE

      Either Left or Right MAIN FUEL PUMP may be selected off.

      (2) MAIN FUEL PUMP (Left or Right) OFF

      NOTE

      Fuel balance can be maintained by opening the FUEL INTERTANK and using the side slip technique.

      (3) Fuel Balance Monitor and Maintain

      (a) Refer to 02-08-60, Fuel Balancing in Flight.

      NOTE

      Only DU1 and DU4 are available when using the RAT. To view synoptic/system pages on DU 4, refer to 03-16-40, DU Unlatch.

      FMS 2 will be inoperative when using the RAT and therefore FMS 1 or FMS 3 must be selected via TSC NAV SRC to view the FMS flight plan on the MAP.

      (4) MAIN BATTERIES and FCS BATTERIES Amps . . . Monitor

    10. Airplane Land as soon as possible
  11. Approach
    1. FLAPS . . . 20°
    2. NOTE

      RAT Gen will drop off line below approximately 200 KCAS. To prevent the RAT generator from repeatedly shedding the load then resupplying electrical power, it must be selected OFF prior to decelerating below 200 KCAS.

    3. RAT GEN . . . OFF
    4. LANDING GEAR . . . DOWN
    5. FLAPS . . . 39°
    6. CAUTION

      THRUST REVERSERS WILL NOT BE AVAILABLE.

  12. Landing . . . Perform
  13. If a go-around is performed:
    1. RAT GEN ON (above 200 KCAS)
  14. Final Approach
    1. Repeat Step 9 and Step 10.

References

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

Revision: 2019-04-30
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