Hydraulics Flashcards
What are the hydraulic systems?
System A, System B, Standby System
What is the normal hydraulic pressure range and how are the reservoirs pressurized.
3000psi +/- 200
Reservoirs are pressurized by regulated bleed air (45-50psi)
What are some components of Hydraulic System A? System B?
System A: Primary Flight Controls, Landing gear, Spoilers
System B: Primary Flight Controls, Brakes, Leading Edge Flaps, and Slats
What Flight Deck indications indicate a refill of a hydraulic reservoir is necessary? When would you see it?
An RF next to the hydraulic quantity display on the lower DU.
When aircraft is on the ground with both engines shut down, or after landing with flaps up during taxi-in.
What precautions, if any, should be taken when turning on the ELEC HYD pumps?
Placing both on simultaneously may create an amperage surge resulting in pump motor circuit breakers tripping in the E/E compartment.
What is indicated by a HYD LOW PRESSURE (amber) light? OVERHEAT (amber) light?
LOW PRESSURE: when illuminated, indicates the respective pump output pressure is low.
OVERHEAT: when illuminated, indicates an overheat condition is detected in the respective system.
Which hydraulic system reservoirs have a standpipe? What quantity percentage do the standpipes protect the reservoir to?
Systems A & B
System A: 20%
System B: 0%
What component(s) does the Hydraulic System A reservoir standpipe protect? System B standpipe?
System A standpipe allows hydraulic pressure to be maintained by the electric motor driven pump
System B standpipe is sufficient for Power Transfer Unit operation.
With zero indicated on the System B reservoir, can the PTU still operate?
Yes
What’s the purpose of the PTU? What Flight Deck indication do we have?
Provide System B fluid at a flow rate (6.5gpm) and pressure sufficient to provide normal rates of operation for the Autoslats and Leading Edge Devices
What could cause variations in the Hydraulic Quantity Indications?
-Pressurization after engine start
-Landing Gear Operation
-Leading Edge Device Operation
-Cold Soaking
What happens when placing a FLT CONTROL switch to STBY RUD?
-activates standby electric motor-driven pump
-shuts of the related hydraulic system pressure to ailerons, elevators and rudder by closing the flight control shuttoff valve
-opens the standby rudder shutoff valve
-allows the Standby System to power the rudder and thrust reversers
What would cause the automatic operation of the Standby Hydraulic System?
flaps extended, and airborne, or wheel speed greater than 60 kts, and loss of System A or B, with the respective FLT CONTROL switch positioned to ON.
or
The main PCU Force Flight Monitor trips
How is low quantity of the Standby Hydraulic System indicated? When would this indication occur?
STANDBY HYD LOW QUANTITY (amber) light. Illuminates when the output pressure of the Standby Hydraulic pump is low, as sensed by a pressure switch. The light is only armed when the standby hydraulic pump control circuit has been activated
The purpose of the PTU is to provide Hydraulic System B fluid at a flow rate and pressure sufficient to provide normal rates of operations for the ________ and __________ in the event the Hydrualic System B Engine Drive Pump output pressure drops below a specific value.
Autoslats and Leading Edge Devices
