Hydraulic System Flashcards
Utility PSI
3,000 psi
Hyd 3000psi Limits
2600-3300 psi
Hyd 5000psi Limits
4500-5400 psi
High Mode Pump
> 380 KCAS
High Mode Pump Single Engine
> 500 KCAS
RLS (Reservoir Leak Sensing) Scheduling
50% fluid - A off
30% fluid - A on, B off
15% fluid - Both A and B on
Brake ACC Norm
3000 psi
10 Brake Applications
BRK ACC Caution
2000 psi
5 Brake applications
Brake ACC preflight Min
2600 psi
APU ACCUM Caution
2450 psi
APU ACC Gauge
3000 psi
Under right wheel well
HYD 1 Powers
Flight Controls only
Pump on left AMAD
HYD 2 Powers
Flight Controls and Utilities
Pump mounted on Right AMAD
Larger reservoir due to utilities
Switching Valves
Located on all flight controls and activates when primary circuit pressure
APU & Brake Accumulators
3000 psi each
Both maintain pressure by trickle-charge from HYD 2A
APU Accum Recharge
HYD ISOL to ORIDE from HYD 2B
- Recharge requires about 20sec following emerg gear ext
- 40sec following in-flight APU Start
Can recharge on ground with hand pump in right wheel well
BRK ACCUUM Recharge
HYD ISOL to ORIDE with Emergency Gear probe to open arm valve
APU Accumulator
Normally used for engine start
With HYD 2 Fail, APU Accum powers
- In Flight: Emergency Gear and Emergency Probe
- On Deck: Emergency NWS and Emergency Brake
Gear Extension
Electrically controlled, hydraulically powered by HYD 2A
If nose WonW switch or launch bar failed to retract, nose gear will not retract but main gears will
Emergency Landing Gear Extension
Mechanically controlled, Hydraulically actuated by APU Accum
APU Accum unlocks doors, releases uplocks, pushes downlock actuators in nose & main gear
This can be done with gear handle up or down, gear will free fall and must be
Downlock Oride
Overrides solenoid to retract mechanical stop and moves landing gear handle up
If failed, could indicate gear problems so only cycle gear if in emergency
Wheel Warning
Gear Warning comes on:
- Gear not down and locked
- 7500 ft
- -250ft/min rate of descent
Tone will sound
- Red gear light on >15sec
Flashing green main gear light
- Planing Link Failure
NWS Low/High
Low - 22.5 deg
High - 75 deg
NWS Powered By
Pri - HYD 2A
Sec- HYD 2B
Tertiary - APU Accum
EMERG NWS
Emerg Hi Gain NWS with FCS CH2 or CH4 fail
Pull FCS CB
Unlock Wings
Press NWS button
HYD Caution
Comes on at 1400psi
Anti Skid Inoperative if
Anti Skid Wheel Spin Up
Activates at 50kts to allow normal braking if right WonW switch fails
Anti Skid - Skid Control
Limits HYD 2A pressure to both brakes as required if wheel speed is not right (skid detection)
Locked Wheel Protection
If one wheel speed is 40% less than other, dumps break pressure to both until wheel speeds match within 40%, disabled below 35kts
Anti Skid IBIT
Activated when gear is lowered, SKID switch turned from off to on, or on ground with parking break set
Starts after 9 sec, takes 4.5 secs, stopped if parking brake released
Parking Brake Set Runs…
Anti Skid BIT, GEN TIE Logic, and INS Alignment
PARK BRAKE Caution
Comes on if parking brake is set and N2 is >80%
Launch Bar
Powered by HYD 2A to extend and hold down launch bar
Failure to put Launch Bar in to retract on cat shot could lead to loss of HYD 2A
Arresting Hook
Powered by HYD 2B to retract to overcome snubber pressure
Power Transmission Shaft Failure
GEN, DC FAIL, BOOST LO, HYD A, HYD B, no pressure fluctuations
Single Circuit Hyd Failure
All flight controls operative
Dual Circuit 1A&1B or 2A&2B Caused by
- Hyd Pump Failure
- Hyd Pump Shaft Shear
- Hyd 1/2 Leak (RLS sequencing)
- Power Transmission Shaft Failure
Any Other Dual Circuit other than 1A/B or 2A/B
Will result in degraded flight qualities but will be controllable
