Equipment Cooling

Question 1

Equipment cooling provides cooling air for what compartments and systems?

Answer 1

• Flight Deck Equip

- Electrical & Equipment Racks

Question 2

What is the source of equipment cooling air for the flight deck?

Answer 2

With 2 or 3 packs operating, the flight deck equipment cooling source valve directs conditioned air into flight deck electrical equipment.

Question 3

If EICAS message EQUIP COOLING is displayed after you’ve switched to STBY mode with engines running, what has occurred?

Answer 3

• Airflow is inadequate
• Overheat is detected
• Smoke is detected
• Ground exhaust valve is not in commanded position

Question 4

A CLOSED loop of equipment cooling will stop what two fans?

Answer 4

Exhaust and Supply

Question 5

Does the bypass valve OPEN in a CLOSED loop configuration?

Answer 5

YES

• Exhaust and Supply fans turns off

Question 6

Under what conditions would the equipment cooling system revert to a closed-loop mode?

Answer 6

• If an internal fan fails
• MAIN CARGO FIRE switch pushed
• LLCCAFR in FWD LOW/FWD HIGH/BOTH LOW with forward lobe temp selector set lower than 10C

Question 7

In flight configuration of the equipment cooling system depends on?

Answer 7

LLCCAFR position and temp selected by FWD Lower Lobe Temperature Selector.

• With temp selected lower than 10C or the LLCCARF in FWD LOW/FWD HIGH/BOTH LOW - closed loop mode is selected.

Question 8

EQUIP COOLING - NORM - GROUND - NO ENG

Answer 8

• Exhausts overboard if ambient temp above 7C.

- Exhausts into FWD LLC if ambient temp below 7C.

Question 9

EQUIP COOLING - NORM - GROUND - 2 ENG - LLCCAFR OFF

Answer 9

• Enters flight configuration
• Exhausts into FWD LLC if:
• LLCCAFR is in OFF, AFT LOW, or AFT HIGH

Question 10

EQUIP COOLING - NORM - GROUND - 2 ENG - LLCAFR BOTH LOW

Answer 10

• If FWD LLC Temp selected to less than 10C or LLCCARF is in FWD LOW/FWD HIGH/BOTH LOW:
• Inboard Exhaust Valve - CLOSED
• Closed Loop Mode entered

Question 11

EQUIP COOLING - STBY

Answer 11

• Ground Exhaust Valve CLOSED
• Auto control bypassed to config for flight
• Inboard Exhaust Valve OPEN
• Single Fault = Closed Loop Mode

Question 12

EQUIP COOLING - OVRD

Answer 12

• Inboard Exhaust Valve - CLOSED
• Ground Exhaust Valve - CLOSED
• Equip Supply Valve - CLOSED
• Smoke/Override Valve - OPEN
• Diff Pressure exhausts cooling air overboard