Hydraulic Flashcards
All components of the hydraulics system receive __________ with the exception of _________ which receives ___________.
3000 psi
Pitch and roll trim actuators
1000 psi
The backup Hyd pump is________ driven.
Electric motor
If there is a BACKUP PUMP PWR circuit breaker out and a condition exsists that requires the pump to operate then ________
The system must be configured so that the backup pump will not come on when you reset the CB or
AC power must be secured prior to resetting the the CB.
Backup pump initiation with AFCS heading hold engaged may cause?
Heading hold failure. Can be reset by pressing the cubes.
FLIR may fail if ___________
Backup hyd pump is turned on with FLIR operating.
The Backup HYD pump will turn on in _______ if on ________ or ____ if on ________.
4 seconds, APU or EXT power
.5 seconds, if either main generator is running.
With WOW and Backup HYD Pump in OFF, ON, and AUTO?
OFF- pump is off.
ON- pump recirculates fluid to and from each transfer module and maintains pressure in the APU accumulator and rescue hoist systems, as required.
AUTO- pump automatically maintains Hyd pressure to the No. 1 and/or No. 2 Hyd systems, including the second stage of the tail rotor servo (as required for hyd system pressure and/or fluid losses detected by the LDI)
Without the WOW and the back up pump in OFF/AUTO, and ON?
OFF/AUTO- pump automatically maintains Hyd pressure to the No. 1 and/or No. 2 Hyd systems, including the second stage of the tail rotor servo (as required for hyd system pressure and/or fluid losses detected by the LDI)
ON- pump recirculates fluid to and from each transfer module and maintains pressure in the APU accumulator and rescue hoist systems, as required.
When APU accum px is low and Backup is activated the pump will run for_____
90 seconds (180 seconds w/winterization kit), regardless of switch position.
Conditions that cause automatic backup pump module operation to be initiated:
- # 1 HYD PUMP
- # 2 HYD PUMP
- # 1 RSVR LOW
- # 1 TAIL RTR SERVO
Utility module routes backup Hyd fluid to the _________
No. 1 and 2 transfer modules
2nd stage of the tail rotor servo
Rescue hoist
APU accum
The priority valve will do what?
Will restrict hydraulic fluid to the rescue hoist in the event that back up hydraulic pressure decreases below a prescribed value.
It’s located between the utility module and the rescue hoist
The velocity fuse will?
Secure hydraulic fluid to APU accumulator if the flow rate exceeds a prescribed limit.
It’s located between the utility module and the APU
How do you reset the LDI logic?
Cycling the HYD LEAK TEST switch
What 5 thing do you need for the HYD LEAK TEST?
BARWA
- BACKUP PUMP AUTO
- AC power
- Rotors engaged
- WOW
- All reservoirs full
What lights indicate a good HYD LEAK TEST?
- 3 RSVR LOW = #1/#2 and BACKUP
- SAS
- BOOST SERVO OFF
- AFCS DEGRADED
- # 1 TAIL RTR SERVO
- # 2 TAIL RTR SERVO ON
- BACKUP PUMP ON
- MASTER CAUTION
Utility pump system numbers and note?
1000 psi with switch OFF
3000 psi with switch ON
When not required, utility pump should be off.
Hydraulic system components:
Three identical and interchangeable Hyd pumps Two Transfer Modules One Utility Module Three dual-stage primary servos tail rotor servos Pilot-assist servo assembly APU accumulator Rescue hoist
When does the HYD warning illuminate?
When the hydraulic system is severely degraded as a result of several compound malfunctions involving the No. 1, No. 2, and backup hydraulic systems
No. 1 and No. 2 Hydraulic system operate with ___.
Rotors turning
No. 1 Hyd system components
No. 1 Hyd pump
No. 1 Transfer module
First stage of the Primary servos
First stage of the tail rotor servo
Where is the No. 1 Hyd pump and what is it driven by?
Mounted on, and driven by, the left accessory module.
Of the pressure and return filters, which can be bypassed, and which can’t?
The Pressure filter has no bypass valve, but the Return filter does
When do you get the #1/#2 RSVR LOW caution?
When the automatic low-level sensing switch, mounted on top of the pump, closes.
What is the job of the Transfer module?
It routes hydraulic fluid from the Hyd pumps to the primary servos and the (#1)first stage of the tail rotor servo or the (#2) Pilot-assist servo assembly. It also automatically routes hyd fluid from the backup pump if hyd pressure is lost.
What are the components of the No. 1 transfer module?
Transfer/shuttle valve, pressure switch, first-stage primary servo shutoff valve, and first-stage tail rotor servo shutoff valve.
What does the Transfer/shuttle valve do?
If Hyd system pressure is lost, it routes backup pump hyd fluid to the primary servos and the (#1)first stage of the tail rotor servo or the (#2) Pilot-assist servo assembly
What does the pressure switch do?
It illuminates the #1/#2 HYD PUMP caution and sends a signal to the LDI when hyd pump pressure drops below a prescribed limit.
Where is the No. 2 Hyd pump and what is it driven by?
Mounted on, and driven by, the right accessory module.
No. 2 Hyd System components
No. 2 Hyd pump
No. 2 Transfer module
Second-stage primary servos
Pilot-assist servo assembly
How can you secure the Hyd pressure to the pitch and roll trim actuators?
by depressing the TRIM pushbutton on the AFCS CONTROL panel.
How can you secure the Hyd pressure to the boost servos (collective, pitch, yaw) and Stability Augmentation System (SAS) actuators?
By depressing the SAS/BOOST pushbutton on the AFCS CONTROL panel.
What does the electrical interlock in the primary servos do?
It prevents you from securing the hyd pressure to both Primary servo stages simultaneously, and, in the event of a malfunctioning stage, precludes accidentally securing the operable stage
The backup Hyd system supplies hyd pressure to the No. 1 and No. 2 Hyd systems ____, and provides hyd pressure to the _____ and _____.
Prior to rotor engagement
Rescue Hoist system
Recharges the APU accumulator
When the backup pump is supplying pressure to the #2 tail rotor servo, the ____ may secure hyd pressure to the rescue hoist due to low system pressure.
Priority Valve
If there is a leak in the No. 1 Hyd system, where does the LDI system assume the leak is?
In the No. 2 Hyd system?
First stage of the tail rotor servo.
Pilot-assist servo assembly
What does the utility hyd system do?
Independently operates the sonar reeling machine.
Operates only when the main transmission is turning
What does the hyd leak test check?
All hyd circuitry except transfer/shuttle valve operation
System is designed to operate as a
dual-isolation distribution system
How is redundancy accomplished?
via electric motor-driven backup pump
Utility hyd pump provides px for
sonar reeling machine
No 1 hyd system operates with
rotors turning
What prevents securing of hyd px to both stages simultaneously (even if one side is malfunctioning)
electrical interlock
backup hyd system provides px to hyd systems
before rotor engagement
Backup hyd system provides px to
rescue hoist system, recharges APU accum
what causes BACKUP RSVR LOW caution to appear?
automatic low-level sensing switch mounted on top of the pump
applying power to backup pump causes a startup power transient to ___ power, possibly resulting in low power alert for __
400 Hz, radar
TAIL SERVO switch positions
NORM - first stage of TR servo is powered by No 1 hyd system
BKUP - backup pump pressurizes second stage of TR servo via utility module
utility hyd pump energized
closes bypass valve which increases px to 3000 psi for sonar reeling machine operation
Utility hyd pump operates only when
main transmission is turning
