HYDRAULICS PANEL

Question 1

LOW PRESSURE Lights_HYD A & B

Answer 1

Illuminated (amber):

• output pressure of associated pump is low
• NOTE: when Eng Fire Switch is pulled, these lights are DEACTIVATED and fluid flow to the pump itself is shut off.

Question 2

OVERHEAT Light

What do illumination of the Overheat lights indicate? (1sp)

(b) what could cause this?

Answer 2

[1sp: it means the fluid in the case drain or pump housing is too hot or electrical pump overheated

(b) could be l_ow hyd qty, or even a low fuel tank qty_ - hyd fluid is cooled by heat exchangers only in the main fuel tanks ]

Illuminated (amber):

• this means that the fluid that is used to cool and lubricate the related electric pump has either overheated OR the pump itself has overheated.

Question 3

ENG HYD PUMP Switches

Answer 3

OFF:

• energizes blocking valve to block pump output
• turning OFF does NOT stop the pump rotation just reroutes fluid back to reservoir
• Note: with loss of normal electrical power, the depressuirization solenoid valve is NOT energized and pump output pressure is restored (in other words with loss of normal power, if the switch is ON and working a loss of power does not impact flow or pressure)

ON:

• DE-ENERGIZES blocking valve in the pump to allow pump pressure to enter system
• ** recommended to leave these pump switches ON at shutdown to prolong solenoid life

Question 4

ELECTRIC HYD PUMP Switches

Answer 4

OFF:

• electrical power removed from the pump

ON:

• provides power to the associated electric motor driven pump

Question 5

How many hydraulic pumps are installed on the aircraft? (1sp)

Answer 5

5 or 6 depending on your viewpoint.

2 mechanical (Eng 1 &2 pumps)

2 electrical

1 standby

1 PTU

Question 6

How does the PTU work? (1sp)

Answer 6

• PTU activates when we have low output pressure from hyd sys B ENG DRIVEN PUMP - it uses A system pressure with B system fluid to operate leading edge devices and autoslats. (1sp)