HYDRAULICS

Question 1

What is the main source of hydraulic pressure for the hydraulic systems?

Answer 1

The L/R hydraulic pumps driven by the prop gearbox

Question 2

What flow rate and pressure to the engine driven pumps provide?

Answer 2

Variable rate constant pressure 3000PSI

Question 3

What is the purpose of the standby system? When will the STBY pumps operate with the STBY HYD switch set to normal?

Answer 3

The standby system is there in the event of main system failure and to support in high workload. They are on when selected or when flaps >0. They will also activate of pressure drops below 2000PSI, or return <20PSI

Question 4

Where are the SPUs located? How are they powered?

Answer 4

The No 2 SPU is in the tail section. No.1 in the nacelle. They are powered from the opposite side 115VAC bus however the No.2 can run off the same side bus.

Question 5

What pressure can the standby pumps produce?

Answer 5

2900PSI

Question 6

What hydraulic system pressure indications are there? You have completed the DESCENT / APPROACH checklist and as a result have the STBY HYD PUMP switches ON. The # NO 1 ENG HYD PUMP caution light illuminates what does this tell you? What will the No.1 MAIN HYD pressure indicator display?

Answer 6

LR standby and main system, the main system will indicate SBY aswell. The no.1 engine hyd pump pressure is below 2000PSI, the main pressure indicator will read the same as the standby.

Question 7

What does a HYD FLUID HOT light tell you?

Answer 7

Fluid in the reservoir has exceeded 109deg

Question 8

When will an ENG HYD PUMP caution light illuminate?

Answer 8

When output pressure drops below 2000PSI

Question 9

What does a STBY HYD PUMP HOT caution light tell you? What can you do about it?

Answer 9

The windings in the pump have overheated. the pump can be switched off.

Question 10

Where is hydraulic reservoir quantity indicated?

Answer 10

In the nacelles and on the co-pilot panel, nacelles are the primary indicators.

Question 11

What sub-systems are serviced by system number one and two?

Answer 11

No.1 Brakes, Flaps, Anti-skid, Inboard roll spoilers, Rudder lower actuator
No.2 Landing gear, Outboard roll spoilers, Nose steering, Emergency brakes, Rudder upper actuator.

Question 12

Can hydraulic fluid supply ever be cut off from a pump?

Answer 12

Yes by pulling the pull fuel off handle

Question 13

How are the HYD reservoirs pressurized?

Answer 13

System pressure via a differential piston to 40PSI.

Question 14

What is the purpose of the PTU?

Answer 14

The PTU uses No.1 system pressure to drive the No.2 system (ARPS). or the gear only if RHIV.

Question 15

When will the PTU operate?

Answer 15

If the No.2 system pressure drops and gear is selected up. or when switched on, 5min time limit RHIV

Question 16

How is PTU operation verified?

Answer 16

The light illuminates on the switch and can be heard.

Question 17

What pressure is the PTU capable of producing?

Answer 17

2700PSI

Question 18

ZZN is fitted with Rudder Isolation Valves. What is the purpose of these valves and how do they operate? How long will the HRIS work for? What system is the rest of the fleet fitted with to ensure rudder operation continues if hydraulic fluid is lost?

Answer 18

If reservoir QTY drops below 0.7 QTS they will isolate the rudder and open again if QTY drops to 0. The rest of the fleet has ARPS.

Question 19

ZZN - What does the PTU supply? Is PTU operation limited? What about the rest of the fleet?

Answer 19

Landing gear only and limited to 5 mins.

Question 20

As discussed previously all aircraft in the fleet except ZZN are fitted with ARPS. Describe the ARPS system? What does ARPS supply? When will ARPS operate and how long is it good for?

Answer 20

The ARPS system isolates the rudder and No.2 SPU if pressure drops to 18PSI and can operate for 30minutes at an assumed leakage rate.

Question 21

What are the minimum dispatch HYD fluid quantities?

Answer 21

L 1.5QTS, R 3QTS

Question 22

Tell me what you know about the EMERGENCY HYDRAULIC STSYEM?

Answer 22

The emergency hydraulic system is there to pump the main gear down in the even of a hydraulic failure.

Question 23

How many hydraulic systems are there on the Dash 8 aircraft?

Answer 23

L/R and emergency.

Question 24

What does the #@ SPU AUX PWR caution light tell you? What should you do?

Answer 24

The No.2 SPU is running off the No.2 AC bus. Monitor the load and volts and consult the QRH

Question 25

How do you know that the rudder shut off valve has closed following loss of fluid in the No.2 system?

Answer 25

RUD FULL PRESS caution light will illuminate