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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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06/21/21

Message Overview:

Message Name:

AUTOTHROTTLE DOES NOT RETARD ON LANDING

Message Code: 223OBS001
Effectivity: All
System: Autothrottle
System Description: 22-30-00
Schematic Diagram: 34-44-00 [ Global  Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 34-44-01 [ Global  Express ]  [ G5000 ]  [ Global XRS ]

Message Description:

Autothrottle did not retard during the landing phase. There was no change in Thrust power when aircraft altitude reached 50 feet.

Possible Causes:

  • Radio Altimeter (RAD ALT) Transceiver 1 (A427)
  • Radio Altimeter (RAD ALT) Transceiver 2 (A426)
  • RAD ALT 1 Receive (RX) Antenna (E111)
  • RAD ALT 1 Transmit (TX) Antenna (E113)
  • RAD ALT 2 Receive (RX) Antenna (E110)
  • RAD ALT 2 Transmit (TX) Antenna (E112)
  • Antenna Coaxial cable
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

NOTE: An undetected failure with the Radio Altitude system could cause a malfunction of the Autothrottle system.

Quick Links:

Operational Test of the Autothrottle System AMM 22-30-00-710-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Operational Test of the Radio Altimeter System AMM 34-44-00-710-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Radio Altimeter Transceivers AMM 34-44-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Radio Altimeter Transceivers AMM 34-44-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Radio Altimeter Antennas AMM 34-44-05-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Radio Altimeter Antennas AMM 34-44-05-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
General Visual Inspection of the L/HIRF Protection of the Radio Altimeter Antennas Connectors AMM 34-44-05-210-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Gather information. Find out what side the Autothrottle was coupled to when the issue occurred. You may ask the crew that experienced the issue if a red RAD flag was displayed on the PFD at the time of failure. There is also a chance that the altitude call-outs did not take place during descent.
  2. Perform the operational check of the RAD ALT system.
  3. Physically inspect the affected RAD ALT transceiver.

    1. If no defects are found continue with next step.
    2. If defects are found, rectify/replace as required.

  4. Remove the affected RAD ALT transceiver. Inspect the connectors for proper installation, damage, moisture and contamination.

    1. If no defects are found continue with next step.
    2. If defects are found, rectify/replace as required.

  5. Swap the affected RAD ALT transceiver with the other RAD ALT transceiver. Is the fault still present?

    1. If YES, continue with next step.
    2. If NO, replace defective RAD ALT Transceiver.

  6. Perform a continuity check of the coaxial cables between the RAD ALT Transceiver and the RX and TX antennas. You may also use a Time Domain Reflectometer (TDR) to detect partial damage or kinks in the coaxial cables that may affect transmission of the radio signals. Cable length is approximately 10 feet.

    1. If no defects are found continue with next step.
    2. If defects are found, rectify/replace as required.

  7. Perform a bonding check of the Antennas.

    1. If bonding is good, replace the antennas.
    2. If bonding is not good, rectify as required.

  8. Do close out.

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