Air Conditioning

Question 1

Controlling temperature in cabin with toggle switch, the RAM air modulating valve to change from hot to cold or vice versa takes about..

Answer 1

15 seconds

Question 2

AIR DUCT O’HEAT annunciator illuminates when….

Answer 2

Temperature of air in the duct to the cabin is too hot (>149°C)

Question 3

How can the windshield anti ice shutoff valve be opened (3)…

Answer 3

• loss of DC power
• select windshield anti ice to HI or LOW
• select EMER mode

Question 4

Hot engine bleed air thru the precooler is FURTHER cooled by….

Answer 4

Pylon ram scoop air

Question 5

RAM AIR modulating valve has what function…

Answer 5

To regulate temperature of cabin air in both modes, means AUTO or MANUAL

Question 6

Source of bleed air when in EMER PRESS is….

Answer 6

Either left or right or both engines

Question 7

Vapor cycle compressor may be on (green light on), when …. (3)….

Answer 7

• air conditioning is in AUTO with ram air modulating valve fully open
• any altitude in AUTO
• On ground without ram air, with ram air valve fully open and cabin temperature higher then selected

Question 8

Vapor cycle compressor is OFF (green light off), when…(3)….

Answer 8

• AIR COND CB is popped
• ram air modulating valve more than 50% bleed on AUTO
• automatic load shedding circuit during engine or generator failure

Question 9

What conditions close the PRSOVs….

Answer 9

• selecting L or R at AIR SOURCE SELECT
• selecting FRESH AIR, EMER or OFF on AIR SOURCE SEL
• in AUTO during cabin taxi temperature over 18°C, the temperature sensor closed the PRSOVs

Question 10

Pilots foot warmers are located where….

Answer 10

Under each pilots rudder pedals

Question 11

Forward fan in AUTO, this fan is operating only when..

Answer 11

When the compressor is ON, and operating at low speed

Question 12

AFT fan has which settings…

Answer 12

FLOOD, LOW, HIGH

Question 13

FWD fan has which settings…

Answer 13

AUTO, LOW, HI

Question 14

In climb and cruise the COCKPIT AIR DIST knob is selected to….

Answer 14

NORM, 50 crew, 50 cabin

Question 15

Cabin air is distributed via (3)…

Answer 15

• forward evaporator
• aft evaporator
• the aft one provides air to overhead WEMACS

Question 16

Cabin air temp is in AUTO mode, what temp range is selectable….

Answer 16

18 to 29 C, or 65 to 85 F

Question 17

What controls does the ram air modulating valve control…

Answer 17

Amount of cooling ram inlet air that passes thru the main cabin heat exchanger

Question 18

CABIN SEL knob to FRESH AIR, what happens…

Answer 18

De-pressurization of the cabin

Question 19

GPU on ground connected. Powering the compressor and both evaporators are in AUTO. Pilot concerned that no cool air is venting into the cabins overhead WEMACS when AFT FLOOD fan switch is in HI or LOW (third position would be FLOOD)

Answer 19

Weird answers…..

• that is normal
• flood cooling door spring loads to the flood cool (open) position without 23 psi air
• with either engine running, 23 psi service air closes the flood cooling doors, thus sending all aft evaporator cooling air to the overhead WEMACS