XBLEED FAIL
(Caution)

The amber 'XBLEED FAIL' caution CAS message indicates a failure is detected is indicated by comparing the IASC2 command signal with the position signal of the cross bleed valve (MPE10) received by both IASCs.

• The cross-flow valve has failed in the full closed position, full open position when commanded to another position.

• Isolation Valve (Cross Bleed Valve) (MPE2)
• Junction Box 2 (JB2) DB1
• Air Conditioning/Bleed Control Panel (PL17)
• Integrated Air System Controller (IASC) 1 (A55)
• IASC 2 (A56)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW300-30-0354 - Potential Piccolo Tube Damage When Replacing a Bleed Loop Element

Forum Articles/Infoservice/Newsletter: None

1. Determine the commanded position of the valve and cross check this position either visually or through the IASC LRU Test page, discrete data section.

   1. If the valve is failing when commanded to the closed position, a ground should be on IASC #1 A56P4 pin 35, or IASC #2 A55P4 pin 35. Or the valve should have continuity between pins 4 & 5.
   2. If the valve is failing when commanded to the open position, a ground is sent to the DCU A14BP1 pin 6H where the signal is compared to the XBleed rotary switch. Or the valve should have continuity between pins 3 & 4.

2. Perform wiring checks between the X BLEED switch on the Bleed air control panel and IASC 2.

   1. If defects are found, repair defective wiring as required.
   2. If no defects are found, continue with next step.

3. Perform a continuity check on the Bleed air control panel while activating the XBLEED switch.

   1. If switch is faulty, replace the switch.
   2. If no defects are found, continue with next step.

4. Access the MDC and view fault messages. Select displayed message from menu below:
   Select an MDC Fault Code/Message:B3-008138 - DISAGREE / VALVE OPEN [XBLEED VALVE]B3-008139 - DISAGREE / VALVE CLOSED [XBLEED VALVE]