Message Name:

TRIM AIR SUPPLY OVERHEAT

Message Code:

B3-006360

Associated CAS:

AIR COND TEMP HIGH
(Caution)

The Low Pressure Duct temperature has been detected over its maximum allowed limit of 90°C.

• Integrated Air System Controller 1 (IASC) (A55)
• Integrated Air System Controller 2 (IASC) (A56)
• Cabin Duct Temperature Sensor (MT26)
• Cockpit Duct Temperature Sensor (MT35)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Fault Confirmation Procedure:

1. Message# = 1
2. Fault Logged = AIR,  TAXI
3. Status = OVERHEAT
4. {Term Definitions}

   • IAS2A-65 XX 353 10 EXCT XXXX-XXTX XXXX-XXXX XXXX-XXXX 353A: 26; TRIM AIR SUPPLY OVERHEAT
   • IAS1A-60 XX 353 00 EXCT XXXX-XXTX XXXX-XXXX XXXX-XXXX 353A: 26; TRIM AIR SUPPLY OVERHEAT

1. Do the AMM TASK 21−61−00−710−801 - Operational Test of the Temperature Control and Indication System.
2. Does the Cabin Duct Temperature Sensor (MT26) and Cockpit Duct Temperature Sensor (MT35) indicate within ± 3 ° C of the ambient temperature?

   1. If YES, check the sensor(s) indicating out of temperature limits, go to step 7.
   2. If NO, continue with the next step. 

3. Do wiring check as follows:
   

   Cabin Duct Temp Sensor

   Channel	LRU	From	LRU	To	Expected Result
   A	Cabin Duct Temp Sensor (MT26)	MT26P1-1	IASC 2 (A56)	A56P1-1	Continuity
   A	Cabin Duct Temp Sensor (MT26)	MT26P1-3	IASC 2 (A56)	A56P1-2	Continuity
   B	Cabin Duct Temp Sensor (MT26)	MT26P1-4	IASC 2 (A56)	A56P3-4	Continuity
   B	Cabin Duct Temp Sensor (MT26)	MT26P1-5	IASC 2 (A56)	A56P3-5	Continuity

4. Are results correct?

   1. If YES, continue with the next step.
   2. If NO, repair wiring as required. 

5. Do wiring check as follows:
   

   Cockpit Duct Temp Sensor

   Channel	LRU	From	LRU	To	Expected Result
   A	Cockpit Duct Temp Sensor (MT35)	MT35P1-1	IASC 1 (A55)	A55P1-28	Continuity
   A	Cockpit Duct Temp Sensor (MT35)	MT35P1-3	IASC 1 (A55)	A55P1-29	Continuity
   B	Cockpit Duct Temp Sensor (MT35)	MT35P1-4	IASC 2 (A55)	A56P1-28	Continuity
   B	Cockpit Duct Temp Sensor (MT35)	MT35P1-5	IASC 2 (A55)	A56P1-29	Continuity

6. Are results correct?

   1. If YES, continue with the next step.
   2. If NO, repair wiring as required. 

7. Do wiring check as follows:
   

   LRU	From	LRU	To	Expected Result @ 25C	Expected Result @ 100C
   Cockpit Duct Temp Sensor (MT35)	MT35J1-1	Cockpit Duct Temp Sensor (MT35)	MT35J1-3	2935.00 Ω to 3066.64 Ω	199.24 Ω to 208.17 Ω
   Cockpit Duct Temp Sensor (MT35)	MT35J1-4	Cockpit Duct Temp Sensor (MT35)	MT35J1-5	2935.00 Ω to 3066.64 Ω	199.24 Ω to 208.17 Ω
   Cabin Duct Temp Sensor (MT26)	MT26J1-1	Cabin Duct Temp Sensor (MT26)	MT26J1-3	2935.00 Ω to 3066.64 Ω	199.24 Ω to 208.17 Ω
   Cabin Duct Temp Sensor (MT26)	MT26J1-4	Cabin Duct Temp Sensor (MT26)	MT26J1-5	2935.00 Ω to 3066.64 Ω	199.24 Ω to 208.17 Ω

8. Are results correct?

   1. If YES, Continue with the next step.
   2. If NO, replace defective Duct Temp Sensor.

9. Interchange the IASC 1 (A55) with the IASC 2 (A56).
10. Does the MDC Fault remain posted? 

    1. If YES, replace defective IASC. Do close out.
    2. If NO, continue with the next step. 

11. Do close out.