AIR_AIR CONDITIONING CONTROLS PANEL

Question 1

AIR TEMP Indicator

Answer 1

• indicates temperature at the location selecte by the AIR TEMP source selector.

Question 2

AIR TEMP Source Selector

• 7 positions in 3 groupings -

SUPPLY DUCT: Cont Cab / Fwd / Aft

PASS CAB: Fwd / Aft

PACK: R / L

Answer 2

• SUPPLY DUCT: shows SUPPLY DUCT temps of Cont Cab - Fwd Cab - Aft Cab
• PASS CAB:
  
  • selects forward or aft pax cabin temps
  • there are 2 pax cabin temp sensors in the RIGHT side of cabin
  • does NOT show temp of CONT CAB (this sensor is in theceiling of the cockpit)
• PACK: selects left or right PACK temps

Question 3

TRIM AIR Switch

Answer 3

OFF:

• trim air PRSOV signaled to CLOSE
• all 3 zone trim air systems are mechanically and electrically disabled
• causes trim air system to operate in UNBALANCED AVG mode (ie 2 zone plane)
  
  • left and right controllers will control packs independently
  • Left Pack = controlled via the CONT CAB selector for temp
  • Right Pack = average the demands of FWD and AFT zones

ON:

• trim air PRSOV signaled to OPEN
• causes BOTH packs to be controlled by the zone with the LOWEST temp setting (BALANCED MODE)
• enables the zone trim channels in the pack/zone temp controllers

Question 4

ZONE TEMP Lights

If this light comes on, what does that mean? (1sp)

Answer 4

[1sp: the respective temperature for that particular zone is too high and the respective trim air valve will close.]

Illuminated (Amber):

• CONT CAB:
  
  • indicates a DUCT TEMP OVERHEAT OR
  • failure of the primary AND secondary temp controllers
    
    • if this happens - [ZONE TEMP] can NOT be reset
• FWD / AFT CAB:
  
  • indicates ONLY duct temp overheat

Note:

• any failure affecting the supply of trim air will cause the temp control system to control both pack INDEPENDENTLY
• DUAL CHANNEL - RECALL
  
  • CONT CAB: failure of flight deck PRI OR STBY temp controller
  • FWD/AFT CAB: indicates a failure of the zone temp control
  • lights extinguish when MC is reset

Question 5

ZONE TEMP Selectors

Answer 5

OFF:

• closes the associated trim air modulating valve
• sets a fixed cabin temp for flt deck (75’F) and cabin (65’F)
• Note: placing all 3 selectors to OFF with the new pack flow temp controller and eFLOW valve will cause a fault that must be cleared by Maint.
• if any selector is turned OFF - it is then ignored by the temp controllers with same (low temp) logic

AUTO:

• provides automatic temp control for the associated zones
• manually rotating to C or W manually sets the desired temps

C = 65’F W=85’F