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(WARNING)
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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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07/14/23

Message Overview:

Message Name:

OPN/SHRT/OUT OF RANGE

Message Code:

B3-007021

Associated CAS:

None

Reporting LRU: L COLLECT PROBE
System Description: 28-41-00
Schematic Diagram: 28-41-00
Wiring Diagram: 28-41-13

Message Description:

The FQGC has detected a discrepancy in the left collector tank fuel quantity probe circuit (L probe 9).

  • Left tank quantity and total quantity are replaced with magenta dashes
  • The fault can be triggered by the presence of water in the probe

Possible Causes:

  • Water Contamination
  • Fuel Quantity Gauging Computer FQGC) (A57)
  • Left Fuel Quantity Probe (No.9) (MT107)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin:

Forum Articles/Infoservice/Newsletter: None

  • Because water has a higher dielectric constant than fuel, water in fuel tanks will affect the reading of fuel quantity probes if it comes in contact with them. The reading will become out of range and the FQGC will stop sending fuel quantity for that tank (magenta dashes). At a certain point, enough water in a fuel quantity probe will 'short' the probe's concentric tubes and collapse the oscillator signal feeding all probes for that tank. The FQGC will identify the oscillator as faulty and will shut down the affected tank channel and identify the fault as internal to the FQGC (MDC code B3-006789).
  • Before replacing the FQGC, make sure the failure is not caused by the presence of water in fuel probes.
  • When sumping water from affected fuel tank it is preferable to have fuel probes immersed in fuel, in order for the water to pool at the bottom of the fuel tank.
  • To get most of the water to the bottom of the tank, for T/S purposes do not move aircraft for at least 2 hours before sumping.

Fuel Probes Capacitance
EMPTY TANK FULL TANK OUT OF RANGE
PROBE VALUE pf PROBE VALUE pf VALUE pf
1 29 1 53 <25.88 or >65.1
2 29.1 2 56.8 <25.88 or >65.1
3 29 3 56.8 <25.88 or >65.1
4 34.1 4 67.4 <30.83 or >77.16
5 40.8 5 80.1 <37.13 or >91.93
6 63.8 6 127.1 <58.66 or >146.01
7 59.7 7 118.4 <54.8 or >136.2
8 79.5 8 158.6 <72.94 or >181.43
9 63.7 9 126.9 <58.66 or >146.01
10 66 10 128.2 <121.39 or >138.42

Fault Confirmation Procedure:

  1. Verify if there is a CAS 'Fuel Qty Fail' message associated with Left Fuel Quantity and Total Fuel Quantity dashed out on the synoptic page.
  2. Verify fault code in the MDC (current and fault history).
  3. Verify if Left tank Collector probe capacitance is not within tolerance.

    1. If any of the above step are true, go to TS step 1.
    2. If fault is not confirmed in step A to C, continue to step D.

  4. Reset CB3-C3 FUEL QTY 1 and CB4-C3 FUEL QTY 2.

    1. Make sure Refuel/Defuel panel is set to off.

  5. Do the operational test of the Fuel Quantity and Gauging System.

    1. If BIT test pass, no maintenance action is required.

NOTE: If the failure is not in the current fault, but in the fault history of the MDC, it could be a transitory condition. Make sure the fuel tank is not contaminated with water.

Quick Links:

Pressure Refueling AMM 12-11-01-650-801
Suction Defueling AMM 12-11-09-650-801
Drain Water from the Fuel Tank AMM 28-10-00-680-801
Built-In Test of the Fuel-Quantity Gauging System AMM 28-41-00-740-801
Removal of the Fuel Quantity Computer AMM 28-41-01-000-801
Installation of the Fuel Quantity Computer AMM 28-41-01-400-801
Removal of the Fuel Quantity Probe AMM 28-41-13-000-801
Installation of the Fuel Quantity Probe AMM 28-41-13-400-801
Capacitance Check of the Fuel Quantity Probes AMM 28-41-13-760-801
Cleaning of the Fuel Quantity Probes AMM 28-41-13-160-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02
Electrical Connectors - Maintenance Practice - ALL SPM 20-20-00-02

Troubleshooting Recommendations:

  1. If the MDC fault code is in the FAULT HISTORY and the left fuel tank indication is not dashed, no action is required, but it is recommended to sump fuel from the left collector tank and left tank in case water was the cause of the failure.
  2. If the MDC fault code is in the CURRENT FAULT, do the Capacitance Check of the Fuel Probes.

    1. If the reading for L PR09 is under 58.66pF, check wiring from FQGC to left collector probe. If wiring is found serviceable, replaced probe.
    2. If the reading for L PR09 is over 146.01pF, sump at least 2 gallons of fuel from the left fuel tank and left collector tank or until no water is found. If fault continues, go to next step.

  3. Re-rack the Fuel Quantity Gauging Computer (FQGC). Is the fault message still present?

    1. If YES, go to next step.
    2. If NO, do close out.

  4. Defuel the aircraft. If fault continues, go to next step.
  5. Access the left collector tank.

    1. Check collector probe for loose electrical connections.
    2. Clean probe (AMM 28-41-13-160-801).
    3. If fault continues, go to next step.

  6. Check wiring from FQGC to left collector probe. If wiring is found serviceable, replace collector tank fuel probe.
  7. If fault continues, replace FQGC.
  8. Do close out.

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