PHI GOM S-92 -HYDRAULICS

Question 0

What systems are driven by the #1 Hydraulic System?

Answer 0

#1 SAS
#1 T/R Servo
#1 M/R Servos

Question 1

Five independent hydraulic systems.

Answer 1

1. # 1 Hydraulic System
2. # 2 Hydraulic System
3. # 3 Hydraulic / Utility
4. Wheel Brakes
5. Rotor Brake

Question 2

What systems are driven by the 
#2 Hydraulic System?

Answer 2

#2 SAS
#2 T/R Servo
#2 M/R Servos
Boost

Question 3

What systems are driven by the 
#3 Hydraulic / Utility System?

Answer 3

APU Accumulator
Backup for #1 and #2 System
Cargo Ramp

Landing Gear

Question 4

Should the # 1 or # 2 hydraulic pumps fail, what is the back-up system?

Answer 4

3 Hydraulic / Utility System

Question 5

If the #3 hydraulic pump fails in flight, what functionality of the system is lost?

Is any functionality restored upon landing?

Answer 5

Normal gear extension
APU Accumulator recharge
Ramp operation

Upon landing, the ground pump will provide APU Accumulator and
Ramp operation.

Question 6

What is normal hydraulic system pressure?

Answer 6

3500-4200 PSI (4000)

Some maintenance ref have it at 3800 to 4200.

Question 7

If one hydraulic system loses pressure, can the other be shut off?

Answer 7

No,

an electrical interlock will prevent the disabling of a ‘good’ system in this scenario.

Question 8

If the #2 hydraulic system has a leak past the tail rotor shutoff valve, when will LDI be activated?

Answer 8

When the HYD 2 RESVR LOW caution is set.

Question 9

If the #2 hydraulic system has a leak past the tail rotor shutoff valve, what caution segments and system pressure will be observed in the cockpit?

Answer 9

HYD 2 RSVR LOW
TR SRVO PRES
Normal system pressure,
no degradation of control.

Question 10

If the #2 hydraulic system has a leak prior to the tail rotor shutoff valve, what caution segments and system pressure be observed in the cockpit?

Answer 10

HYD 2 RSVR LOW TR SVO PRES
MR SVO PRSS HYD 2 PUMP FAIL
SAS 2 PRES BOOST PRES
Boost is no longer available so control forces will be heavier, but the helicopter fully controllable.

Question 11

There are “__” main rotor servo actuators mounted on the main gear box.

Answer 11

There are “3” main rotor servo actuators mounted on the main gear box.

Question 12

During normal start and shutdown of the helicopter, at what Ng / Nr speeds do the Back-up isolation valves close and open?

Answer 12

On start, isolation valves close at 15% Ng
and re-opens at 50% Nr.
On shutdown, they close at 50% Nr
and re-opens at 15% Ng after 2 minutes.

Question 13

Why do the Back-up isolation valves open / close (15% Ng / 50% Nr) during normal start and shutdown of the helicopter?

Answer 13

This prevents transfer of hydraulic fluid from the #3 system to the #1 or #2.

Question 14

What conditions must exist to perform the LDI test?

Answer 14

WOW
Rotor brake on
AC power

Question 15

Does the hydraulic system have a filter bypass capability in the event of a clogged filter?

Answer 15

Yes,

but only on the return side to prevent hydrostatic lock.

Question 16

What effect does moving the gear handle have on hydraulic system pressure?

Answer 16

Pressure will increase from depressurized mode of

2000 +/- 1000 to high mode of 4000 psi.

Question 17

How may a pilot or crew member manually lower the ramp in the event of a #3 hydraulic system failure?

Answer 17

Manually release on the ramp control valve.

Question 18

If the collective is lowered too rapidly during runup it may cause the ___caution light to illuminate if the pressure drops below _____.

Answer 18

SAS

1100 psi

Question 19

After shutdown, you can’t move the flight controls. Is this normal? Why?

Answer 19

Yes

For 120 seconds after the last engine is shut down the Backup isolation valve blocks ground pump pressurization of the flight controls.