Foul Weather / AC and PX Systems

Question 1

Two subsystems

Answer 1

Air scoop

Compressor inlet assembly

Question 2

Prop ice control time

Answer 2

160 seconds, 20 seconds each of the cuffs, skirts and islands for 4 engines
76-100 amps in flight, 74-100 on the ground

Question 3

Diffuser anti ice percent drop

Answer 3

9% and 5% increase in FF

Question 4

Timer motor for emp deice

Answer 4

8 seconds per strip with 16 second dead band = total 176 secs

Question 5

Engine and wing use what kind of heat?

Prop and emp?

Answer 5

Air only in normal RPM
Electric low or normal RPM

Memory aid: engines run both on the ground and in the air. Wings only work in the air (norm)

Question 6

Ice detector

• when to use
• power source
• test perameters

Answer 6

• whenever MEAC is powered
• MEAC: probe heater, MEDC: icing light
• N/A

Question 7

Pitot heat

• when to use
• power source
• test perameters

Answer 7

Before start to secure checklist
FEAC: pilot, MEAC(28c fwd lighting): copilot, MEDC: caution lights
N/A

Question 8

AOA heat

• when to use
• power source
• test perameters

Answer 8

Before start to secure checklist
MEDC
N/A

Question 9

Engine

• when to use
• power source
• test perameters

Answer 9

Prior to entering areas where structural icing is likely
MEDC (loss of power)
Normal or low rpm with a TIT increase then TIT decrease and increase

Question 10

Prop

• when to use
• power source
• test perameters

Answer 10

Whenever stuctural icing is evident
BUS B: heater elements, aft lighting trans: GND test, EMDC: control
Reduce voltage; same speed (160 secs for complete cycle)

Question 11

Wing

• when to use
• power source
• test perameters

Answer 11

When ice builds up to .5”
EMDC: mod valves, MEDC: caution lights
10 degrees TIT rise with corresponding wing temp rise

Question 12

EMP

• when to use
• power source
• test perameters

Answer 12

When structural icing is encountered in flight (used with wing deice)
BUS A: parting strips, BUS B: cycling strips, MEAC: timer motor, EMDC: relay control, MEDC: caution lights
Same power; high speed motor; 44 sec vs 176 secs for normal speed

Question 13

Windshield

• when to use
• power source
• test perameters

Answer 13

Before start to secure checklists
MEAC/MEDC: front wiper power control, BUS A/EMDC: side
MEDC: caution lights
N/A

Question 14

Drive spline shear HP

Answer 14

257 HP

Question 15

Relief valve nominal px

PRESS LOW light

Answer 15

100psi

Below 50psi

Question 16

TEMP HIGH Light

Answer 16

Exceeding 121 degrees C

Question 17

Control valves fully open at how many feet?

Answer 17

12,000

Question 18

Heat exchanger REFR OVHT light on at

Answer 18

Exceeding 166 degrees C

Question 19

Automatic temperature control mode range

Answer 19

18-29 C

Question 20

A valve

Answer 20

Turbine bypass valve
Air that is partially cooled by heat exchanger to bypass the fregeratuon turbine unit to enter the flight station or cabin risers

Question 21

B valve

Answer 21

Turbine shutoff valve

Air passes the expansion turbine driving the secondary compressor

Question 22

C valve

Answer 22

Hot air bypass valve (hot compressed air from EDC or multiplier enters the riser)

Question 23

Pressure ratio limiting
Yellow condtion psi
Red condition

Answer 23

72psi

50psi

Question 24

Prop and Emp uses what heat?

Answer 24

Electrical heat

Question 25

Sources of heat

Answer 25

APU, EDC’s, 14th stage bleed air

Question 26

4 functions of the Aux Vent switch placed in the open position

Answer 26

EDC’s dumped
Firewall Shut off valve closes
Outflow valve opens electrically
The valve itself opens fully