the learning never stops!

Flight Control Computer Alternate Mode

G500 Abnormal Procedures

This is a work in progress


AFM Procedure

[AFM, §03-]

Possible Cause

FCC Control Law has transitioned to the alternate mode due to:

  • Less than two valid Inertial Reference signals, or
  • Less than two valid Air Data sources, or
  • Loss of communication from FCC to HSTS
images

Click photo for a larger image

System Impacts

  • AOA: Indication may be unavailable.
  • AOA Limiting: Unavailable.
  • AP DISC / TSS: Will not reset pitch trim.
  • Automatic Turn Coordination: Unavailable.
  • Autopilot: Unavailable.
  • Autothrottle: Unavailable.
  • High Speed Protection: Unavailable.
  • Low Speed Awareness / Warning: Indication may be unavailable.
  • Pitch Limiting Indicator (PLI): Indication may be unavailable.
  • Primary Trim Switch: If the Stab Pri Trim Fail (U) (caution) CAS message is displayed the primary trim switch on sidestick is inoperative
  • Stall Warning (Stick Shaker): If AOA valid will activate 0.85 AOA.
  • teep Approach: Unavailable.

Corrective Action

  1. Airplane . . . Trim stick forces to neutral

  2. FLT CTRL RESET . . . PRESS and RELEASE

  3. If the CAS message is no longer displayed:
  4. a. Flight . . . Continue

  5. If the CAS message remains displayed:
  6. a. Airplane . . . Land as soon as practicable

    b. If the Stab Pri Trim Fail (U) (caution) CAS message is displayed:

    (1) Backup PITCH TRIM . . . Use (as required)

  7. Above 41,000 feet MSL:
  8. NOTE

    AOA limiting, stall protection and high speed protection features are unavailable. Low speed awareness and angle of attack may not be available.

    If angle of attack information is available, stall warning (stick shaker) should activate at 0.85 AOA.

    If unable to increase airspeed, descent may be required at higher altitudes and gross weights to maintain less than 0.65 AOA maximum.

    a. Airspeed . . . 0.85-0.9M / .65 AOA maximum

  9. Above 20,000 feet MSL:
  10. a. Airspeed . . . 250-285 KCAS / .65 AOA maximum

  11. Below 20,000 feet, prior to configuration change:
  12. CAUTION

    WHEN OPERATING IN A DEGRADED FLIGHT CONTROL MODE, THERE ARE TWO FLIGHT CONTROL LAW GAINS. EXTENDING FLAPS TO AT LEAST 10° WHEN OPERATING AT AIRSPEEDS LESS THAN 200 KCAS WILL HELP PREVENT REDUCTION IN AIRPLANE CONTROLLABILITY.

    a. Airspeed (Minimum) . . . 200 KCAS (flaps up)

    b. FLAPS . . . As required

    c. Airspeed (Minimum) . . . VREF +10 KCAS (flaps down)

    d. Runway . . . Select runway based on minimum crosswind (less than 10 knots)

    NOTE

    Landing distance should be based on VREF +10 KCAS to touchdown increased by a 1.25 factor for a shallow approach. Wheel fuse plug release may occur due to added landing speed under combinations of high field elevation, landing weight and OAT.

    e. Landing Distance . . . Recalculate with a 1.25 factor

  13. Approach and Landing
  14. CAUTION

    USE CAUTION DURING FLARE, OR IN GUSTY WIND CONDITIONS, DUE TO DECREASED FLIGHT CONTROL AUTHORITY.

    NOTE

    If angle of attack information is available, maintaining VREF +10 minimum and below 0.65 AOA during approach and landing will ensure adequate maneuvering capability.

    a. Approach . . . Fly shallow approach angle

    b. Airspeed . . . Maintain VREF +10 KCAS

    c. Landing . . . Minimize flare

References

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

Revision: 2019-04-18
Top