hydaulics Flashcards
Engine driven hyd pumps are mounted on what
prop reduction gear box
How many psi do the engine driven pumps deliver
3000 psi
Describe hyd pumps
1 left engine driven w/ standby electric
2 right engine driven w/ PTU
3 DC motor pump
4 alt landing gear (fo driven)
1 Hydraulic System hydraulic pressure for:
Flaps (priority) Anti Skid / Main Brakes (isolation) Inboard Roll Spoilers (isolation) Rudder (lower PCU) Elevator (outboard PCUs) Power Transfer Unit (priority)
1 hyd reservoir capacity and min quantity
8 quart, min 40%
1 standby hyd pump powered by what
AC driven
AC driven standby hyd pump auto activates when
left engine fail in flight or flaps greater than 0 and parking brake is off and number 1 reservoir is not empty and AC power is available (takeoff and landing)
When will the stby hyd press light come on?
When pressing the button to activate the standby hyd pump (does not come on automatically)
If pressure in hyd 1 drops below 2100 psi
Priority valve closes
lose - flaps and PTU
When does the isolation valve close
quantity low
lose: anti-skid/main wheel brakes, inboard roll spoilers
What is the thermal bypass valve?
opens to allow fluid to heat exchanger at certain temperature
What is the purpose of the PTU
power transfer unit serve as a back-up for #2 main hydraulic system
What is the PTU powered by?
Hydraulic system 1
How do you activate the PTU?
Press the PTU CNTRL switch light or automatically
light turns on for both manual and automatic activation of PTU
Describe #2 hyd system
reservoir located in right nacelle, 12 q capacity, min 40%, pressurized by right engine driven pump (EDP)
2 hyd system provides pressure for
Landing Gear Outboard Roll Spoilers Nose wheel steering Emergency / Parking Brakes Rudder (Upper PCU) Elevator (Center PCU)
What do you lose if Hyd system two becomes low?
Isolation valve closes Landing gear Outboard Roll Spoilers Nose wheel steering Emergency/parking brake
When is the PTU on?
Takeoff and landing, when the button is pushed, when system two fails
Automatic PTU operation occurs if
parking brake off and
flaps greater than 0 and
no 1 system press greater than 2400 psi and
hyd no 2 reservoir not empty
When will the PTU shut down
the ptu will shut down and remain latched out if it does not produce pressure for more than 30 seconds when automatically commanded to do so
how is the hyd system cooled
fuel, thermal bypass valve opens to heat exchanger for 1 and 2 systems
Describe hyd system 3
back up system for elevator (inboard PCUs), reservoir located in environmental compartment, 2.6 q capacity min quant 40%, during normal flight in “active standby” with the isolation valve energized closed
hyd 3 is powered by
Dc motor pump at 2600-3250 psi to keep accumulator pumped up
What is the DCMP powered by?
standby battery (hot batt bus)
When will hyd system 3 activate
manually by HYD 3 ISOL VLV switchlight, automatically by lose of syst 1 or 2 and/or dual engine failure
When will you get #3 HYD PUMP caution light
accumulator pressure below 900 psi in flight or
DCMP operates more than 60 seconds on the ground
Firewall shutoff valves operate when
engine 1 or engine 2 pull fuel/hyd off handles pulled
no 1 or no 2 hyd reservoir fluid quantity is low
hydraulic fluid over temp
POWERED BY ESSENTIAL BATBUS
