Hydraulic Flashcards
Pressure to Pitch and roll trim actuators in pilot assist
1000 psi
Pressure of system
3000 psi
LDI
leak detection/isolation system
No.1 Hydraulic powers?
First stage of the primary servos and first stage of the tail rotor servo
What drives No 1/2 pumps
accessory modules
Pump components
Pressure relief valve Bleed valve Pressure filter Return filter Automatic low level sensing Both pressure and return filters have PDI
Filter with bypass
Return filter, Pressure filter has no bypass
Transfer module
Routes fluid
Automatically routes fluid from backup pump if pressure lost through transfer / shuttle valve
Shutoff valves for primary servos and tail rotor servo/pilot assist
No.2 Hyd pump powers what?
Second stage primary servos and pilot assist servo assembly
How to secure pitch and roll trim actuators
Pressing TRIM cube on AFCS
How to secure boost servos and SAS actuators
SAS/BOOST pushbutton
Electrical interlock between first and second stage of primary servos
Prevents securing hydraulic power to both, if malfuntioning stage it precludes inadvertent securing of the good stage
What powers Backup hyd pump
AC electrical motor
Backup hyd pump purpose prior to rotor engagement
Provides pressure to #1/2 hyd systems
Other functions of Backup hyd pump
Pressure to rescue hoist system
Recharges the APU accumulator
What is secured when Backup is supplying pressure to #2 tail rotor servo
Priority valve secures pressure to the rescue hoist
Time to energize the Backup pump
4 seconds with APU, 0.5 seconds with either main generator
Backup pump internal depressurizing valve
reduces the output pressure to aid startup of the electric motor
WOW backup switch functions
OFF- off
ON- recirculates fluid to and from each transfer module, maintains pressure to apu accumulator and rescue hoist
AUTO- Automatically maintains pressure to #1/2 systems and second stage of tail rotor servo as detected by LDI
Weight off wheels
OFF or AUTO - same as WOW auto and pressure to second stage tail rotor if tail servo switch placed to BKUP
Run time if backup hyd pump switch is cycled
90 seconds, 180 seconds with winterization kit
When will Backup pump automatically turn on
#1 HYD PUMP (Loss of pressure) #2 HYD PUMP (Loss of pressure) #1 RSVR LOW #1 TAIL RTR SERVO (Loss of pressure)
Utility module function
Acts as transfer module for Backup pump Has velocity fuse to secure fluid flow to APU accumulator if flow rate is excessive
Requirements for HYD leak test
WOW AC power Rotors engaged All reservoirs full Backup Hyd pump switch in AUTO
What could fail if ON when Backup pump is turned on
FLIR
Backup pump CB popped and you need to trun the backup pump on
Caution make sure the aircraft is configured so the backup pump will not come back on when CB is reset
Indications of HYD leak test
#1 / 2 RSVR LOW BACKUP RSVR LOW SAS BOOST SERVO OFF AFCS DEGRADED #1 / 2 TAIL RTR SERVO BACKUP PUMP ON MASTER CAUTION
Hydraulic fill system
Hand pump and manual selector valve used to fill and service reservoirs
Also serves as rotor brake reservoir
Utility Hyd system
Independently operates the sonar reeling machine
Right rear quarter of the main transmission
Circulates at 1000 PSI when not on
Increases to 3000 PSI when turned on
Three boost servos
Collective, Yaw, and Pitch
All boost servos and roll channel incorporate a SAS actuator which provides rate damping
Roll channel is not boosted, just SAS
