Message Name:

WHEEL SPEED XDCR OUTBD R/BCU/WRG

Message Code:

3245417HA

Right Outboard Wheel Speed Transducer has been detected failed by the Brake Control Unit (BCU).

• Right Outboard Wheel Speed Transducer (WST) (P19)
• Brake Control Unit (BCU) (A71)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW700-32-0138 - Loss of Normal Braking Upon Landing
• AW700-32-0244 - Operational Procedures to Prevent Freezing Brakes
• AW700-32-0359 - Brake Control System - Data Gathering to Reduce the Brake Control Unit (BCU) No-Fault-Found (NFF) rate
• AW700-32-0513 - Wheel Speed Transducer - Brake System Nuisance Fault Messages
• SB700-32-016 - MODIFICATION - BRAKE CONTROL SYSTEM - PART NO. CHANGE OF THE BRAKE CONTROL UNIT TO GW415-7125-5

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

NOTES:

• If you replace a brake system component please fill out this questionnaire.

1. Re-seat the BCU. Is the fault still present?

   1. If NO, do close out.
   2. If YES, continue with next step.

2. Perform the Wheel Speed Transducer - Adjustment/Test. Is the fault still present?

   1. If NO, do close out.
   2. If YES, continue with next step.

3. Disconnect the Right Outboard WST connector (P19). Perform a resistance check as follows:
   For P/N: 27700-103

   From	To	Expected Result	Result
   P19-1	P19-2	Must not exceed 700 Ω
   P19-3	P19-4	Must not exceed 700 Ω

   For P/N: 27700-105
   

   From	To	Expected Result	Result
   P19-1	P19-2	650 ±50 Ω
   P19-3	P19-4	650 ±50 Ω

   For P/N: 27700-107
   

   From	To	Expected Result	Result
   P19-1	P19-2	655 ±35 Ω
   P19-3	P19-4	655 ±35 Ω

   For P/N: 27700-109
   

   From	To	Expected Result	Result
   P19-1	P19-2	620 ±55 Ω
   P19-3	P19-4	620 ±55 Ω

   NOTE: The resistance check must be performed at 70 ±5°F(21 ±3°C). If the temperature is not included in that range, perform the correction of the measurement to 70°F(21°C) with the formulas that follow:

   • Resistance value at 70°F=R1 × [(460.1)/(T1 + 390.1)]
   • Resistance value at 21°C=R1 × [(255.5)/(T1 + 234.5)]
   • T1=Temperature at which it is measured
   • R1=Resistance measured at temperature T1

   1. If resistance values are not within tolerance, replace WST and do close out.
   2. If resistance values are within tolerance, continue with next step.

4. Interchange the Right outboard WST with Left outboard WST. Is the fault still present?

   1. If YES, replace Right outboard WST and do close out.
   2. If NO, continue with next step.

5. Perform wiring checks between the Right outboard WST (P19) and the BCU (A71AP1 and A71BP1).

   1. If wiring checks are not good, repair defective wiring as required and do close out.
   2. If wiring checks are good, continue with next step.

6. Replace BCU.
7. Do close out.