Hydraulics, Brakes & Gear

Question 1

What powers the #3 hydraulic system?

Answer 1

The #3 hydraulic system is powered by a gas charged accumulator. Accumulator pressure is maintained by a DC-Motor-Driven-Pump (DCMP).

SDM 12-3

Question 2

What is the purpose of the PTU?

Answer 2

A Power Transfer Unit (PTU) serves as a back-up pressure source for the #2 Main hydraulic system.

SDM 12-3

Question 3

What powers the PTU?

Answer 3

The PTU (hydraulic motor) is powered by the #1 Main hydraulic system.

SDM 12-3

Question 4

What systems are powered by the #l hydraulic system?

Answer 4

The #1 Main hydraulic system supplies power for the operation of the:

· Flaps 
· Inboard Roll Spoilers 
· Brakes (Main Wheel Brakes) 
· Anti Skid 
· Rudder (Lower Power Control Unit (PCU)) 
· PTU 
· Elevators (Outboard PCU's)
(BARF PIE)

SDM 12-3

Question 5

What backs up the #1 hydraulic pump?

Answer 5

An electrically driven Standby Hydraulic Pump serves as a backup pressure source for the #1 Main hydraulic system.

SDM 12-3

Question 6

When will the STBY HYD PUMP turn on automatically?

Answer 6

The Standby pump will automatically activate when the No. 1 engine fails, or whenever the flaps are selected to any position greater than 0° (the parking brake must be released).

SDM 12-7

Question 7

Will the green ON switchlight illuminate if the STBY HYD PUMP is automatically activated?

Answer 7

No

Question 8

What systems are powered by the #2 hydraulic system?

Answer 8

The #2 Main hydraulic system supplies power for the operation of the:

· Landing Gear 
· Outboard Roll Spoilers 
· Steering 
· Emergency/Parking Brakes 
· Rudder (Upper PCU) 
· Elevators (Center PCUs)
(LOSER E)

SDM 12-4

Question 9

If hydraulic systems #1 & #2 fail, will brakes be available?

Answer 9

A fully charged accumulator is sufficient for approximately six applications of the emergency parking brake lever

SDM 14-11

Question 10

Will the green ON switchlight illuminate if the PTU is automatically activated?

Answer 10

The ON segment (green) of the PTU Switchlight illuminates whenever the PTU is activated either automatically or manually.

SDM 12-8

Question 11

What systems are powered by the #3 hydraulic system

Answer 11

Elevator

Question 12

What is the purpose of the #3 Main Hydraulic system?

Answer 12

If both engines were to fail, leaving both EDPs, the Standby Hydraulic Pump, and the PTU inoperative, the DCMP in the #3 hydraulic system will provide sufficient hydraulic power to the left and right elevator for pitch control.

SDM 12-3

Question 13

What is the minimum hydraulic quantity for dispatch in each system?

Answer 13

40%

Question 14

When will the standby hydraulic pump automatically activate?

Answer 14

The Standby pump will automatically activate when the No. 1 engine fails, or whenever the flaps are selected to any position greater than 0° (the parking brake must be released).

SDM 12-7

Question 15

When will the PTU automatically operate?

Answer 15

The PTU will automatically turn on when the flaps are selected to any position greater than 0° (the parking brake released).

SDM 12-8

Question 16

What is the minimum landing gear strut extension?

Answer 16

• Check for visible piston crome.

NOTE: Contact Maintenance Control if:
• Nose strut extension is less than one inch. (This does not constitute a discrepancy and does not need to be documented in the Maintenance Logbook, but advises Maintenance that strut extension may be less than optimal.)
• No piston chrome is visible during preflight inspection (Maintenance Logbook entry required).
• Nose strut bottoms out during taxi out or in. Nose strut bottoming is evidences by a thumping or banging sound from the nose gear during taxi (Maintenance Logbook entry required).

FSM 3.2.13

Main Gear Strut – Check
• Check strut extension approximately 1.5 to 4.5 inches

FSM 3.2.15

Question 17

What do the gear lights in the floor provide?

Answer 17

An Alternate Downlock Verification system provides a redundant means of confirming gear down and locked.

SDM 14-1

Question 18

What does the landing gear inhibit switch do?

Answer 18

Selecting the switch to INHIBIT disables the electrical command sent to the landing gear solenoid valve for normal extension when the landing gear select handle is moved, preventing normal gear extension.

SDM 14-4

Question 19

Is anti-skid available when using the emergency brake?

Answer 19

No

Question 20

What is the minimum parking brake pressure for engine start?

Answer 20

1000 PSI For starting #1 engine first

500 PSI For starting #2 engine first

Question 21

If sufficient parking brake pressure is not available for engine start, what can be done?

Answer 21

Secure the aircraft to a tug

Increase brake pressure in the right main wheel well with a hand pump

Brief the ground crew to chock the LEFT main gear, in addition to the nose gear. The left main gear shall remain chocked until the number two engine has been started and park brake pressure is indicating 1500 psi minimum.

FSM 7.4.13

Question 22

When would the gear warning tone sound?

Answer 22

A landing gear warning tone sounds over the flight compartment speakers whenever the gear is not down and locked and any of the following conditions exist:

a. Flaps are greater than 8.5° with either engine torque indicating less than 50% and both power levers positioned aft of the RATING detent.
b. Airspeed is less than 156 KIAS with both power levers near the FLIGHT IDLE detent (within approx. 12 °+ of FLIGHT IDLE).

SDM 14-3

Question 23

How far can the nosewheel be turned via the rudder pedals? Via the Tiller? Via Free Caster?

Answer 23

Rudder pedals = 8*

Tiller = 70*

Free caster = 120*