Hydraulic Power Flashcards
What is the purpose of the hydraulic power system?
To provide the hydraulic power necessary to operate:
1) the flight control circuit (MR and TR actuator’s)
2) the utility circuit (LG extension/retraction)
What is the operating pressure of the hydraulic system?
207 bar (3000 psi)
Under what circumstance is HYD SYS 1 used to operate the landing gear?
Only in an emergency
Where is the TRSOV located within the HYD system and what is its purpose?
The number 2 HYD system, to prevent complete loss of hydraulic fluid in the event of a fluid leakage.
What is the number 1 HYD system
used for?
Pre-flight control check on the ground only.
How many hydraulic pumps are there in the system and to which system do they belong?
4 total.
Pump 2 and 4 supply HYD 2.
Pump 1 and 3 supply HYD 1.
NOTE: Pump 3 is electric and is for flight control checks the ground.
Hydraulic pump 3 is driven by an electric motor, what are pumps 1, and 4 driven by?
The MGB.
How long is the timer relay and what is its purpose on the #3 HYD system?
2 minutes to preserve the aircraft battery power.
What is the reduced pressure of the electric hydraulic pump?
105 bar (1523 psi)
What is the purpose of the SOVs in the 1 & 2 HYD SYS?
To isolate the respective flight control circuit in case of overheating.
The three microswitches in each PCM, determine fluid levels at…
50, 28 and 22%
Which filter on the PCMs is provided with a bypass valve, the pressure filter or the return filter?
The return filter only. This allows fluid recirculation in case of filter clogging.
How many clogged filter indicators are there and what are they?
Two.
- Hydraulic Synoptic SYS 1 & 2
- One visual indicator for each filter ( RED POP-OUT)
When a clogged filter indication is discovered after start, can the sortie/mission continue?
Yes. Maintenance shall be carried out at the first shutdown on a maintenance base, but in any case within 10 flight hours.
How many pressure sensors are in HYD SYS 1 & 2 repectively?
8 in SYS 1
9 in SYS 2
How many fluid level microswitches exist in PCM 1 & 2 respectively?
PCM 1 = One (22%)
PCM 2 = Three (50, 28 & 22%)
In PCM 1, what happens if the fluid level reaches 22%?
HYD UTIL PRESS caution illuminates. UTIL SOV1 of the EMER LDG GEAR closes.
In PCM2, what happens if the fluid level reaches 50%?
HYD UTIL PRESS caution illuminates. UTIL SOV2 closes. The LDG gear will drop down due to lack of pressure.
In PCM2, what happens if the fluid level reaches 28%?
TRSOV closes and the UTIL SOV2 re-opens (HYD UTIL PRESS caution extinguishes). The LDG GEAR will retract if the lever is up.
In PCM2, what happens if the fluid level reaches 28%?
HYD UTIL PRESS caution reappears as the UTIL SOV2 closes again.
In case of PUMP 2 failure, can the remaining pump supply the operating pressure to HYD SYS 2?
Yes. PUMP 4 will supply operating pressure.
In case of PUMP 1 failure, can the remaining pump supply the operating pressure to HYD SYS 1?
No. Total loss of HYD SYS 1 will result. PUMP 3 is electric and is used only for ground flight control checks.
What happens to the HYD SOV switch during a low pressure condition?
The switch is inhibited.
What temperature, does the hydraulic 1 or 2 amber TEMP illuminate on the hydraulic control panel?
> 134 degrees
When both 1 HYD OIL TEMP and 2 SERVO cautions are illuminated (or vice versa), what is the warning associated with the SOV switch?
DO NOT SWITCH SOV TO CLOSE ON THE UNAFFECTED SYSTEM SINCE THIS WILL CAUSE LOSS OF CONTROL IN THE AFFECTED SERVO JACK.
At what pressure, does the hydraulic 1 or 2 amber PRESS illuminate on the hydraulic control panel?
< 163 bar
In case of MAU1(2) failure, what information regarding the hydraulic system should be ignored?
The synoptic pages information.
If a hydraulic system SOV has been selected closed due to a system overtemp, what happens to the SOV selection if a drop in pressure occurs in the remaining hydraulic system?
The SOV selection will be overridden and pressure will be reinstated to the servos. NOTE: The physical switch will remain in the selected position.
