Landing Gear Flashcards
How many seconds for extension and retraction of landing gear?
5 sec
Legs of landing gear are kept in close position by
Hydraulic (pressure in the actuator)
Mechanical (locked doors where gear is housed)
Landing gear is kept in open position by
Hydraulic
Mechanical detent incorporated in the actuating cylinder
When the red landing gear lever light illuminates?
Position of the gear is not consistent with position of the lever
RPM<62% below 10.000ft at speed of 165KIAS or below
Landing gear is moving
Emergency extension
Power for landing gear lights and audio warning signal is supplied by
Essential bus
In which cases we are not able to lower the gear with main system?
Hydraulic failure
Electrical failure
What happens when I pull emergency gear extension handle?
Pressure in the line of speedbrake drops, then it is retracted by aerodynamic effect
When extending the gear with emergency system
Gear doors stay open
Red handle light remains illuminated
How long does it take emergency landing gear extension?
20 sec
Where does pressure for emergency gear extension come from?
Emergency hydraulic accumulator
In case of hydraulic pump failure, with still enough pressure in the main system, what allows braking action?
Pressure stored in the main accumulator
Emergency hydraulic system provides pressure for
Emergency landing gear extension
Emergency braking
The anti-skid system is inoperative below what speed?
15kts
Name and explain the 3 anti-skid protections
Touch down protection
Locked wheel protection
Spin up override
Spin up override is used when
Airborne/ground microswitch is faulty, and Touch Down protection remains active after landing
In what case (other than malfunction) the anti-skid system is inoperative?
In case of emergency brake system
Angle of action of NWS
56º
The NWS system is
Electrically controlled (button on the stick)
Hydraulically actuated
NWS is active only
When on ground
When moving the landing gear control lever, the system energizes the
Steering box (but in flight the light must remain off otherwise there is a malunction)
Anti-skid control box
When the NWS is not engaged, its hydraulic pressure is used for what?
To reduce and prevent nose wheel shimmy
Minimum pressure to lower the gear
110bar
The actuation of emergency lending gear extension excludes what systems?
Speedbrake
NWS
Micro switch NOSE
RATS
RNAV heater
AOA heater
TTS heater
Steering
Micro switch LEFT
SERACAP
Salvo jettison
Electrovalve hyd circuit separation
Retraction gear on ground (dn lock overr)
Anti-skid
Canopy seal
Anti-ice engine
Pitot annunciators
Micro switch right
SERA
Salvo jettison
Electrovalve for hyd circuit separation
Retraction of gear on ground (dn lock ov)
Anti-skid
Tyre pressure main gear
7.5 to 10 bars
Nose wheel pressure
5 bar
Minimum pressure for NWS system
70-80 bar
Minimum turn radius with NWS
8.60 mt
The landing gear struct substains sink rate up to
720 ft/min
Sequence extension of landing gear
Handle
Door closed MW
Leg closed MW
Actuators for gear extension
Lights illuminate in the cockpit
Door open MW
Door closed MW
Lights in the cockpit off
During retraction sequence is inverted
Emergency hyd system valves for emergency brake and emergency gear extension is located where?
In the speedbrake bay
What are the valves located in the speedbrake bay and related to emergency hyd system?
Emergency brake and parking valve
Selector valve
Pression valve (right priority)
When main gear tyre are worn out?
When you see 2nd canvas overlaying 90º the first 1
(14 canvas total)
When nose tyre is considered worn out?
When the chined Tyre is smooth for at least 50% of its circumference
Max Tyre speed
139kts
Describe the brake system without anti-skid
Hydraulic pressure is sent by applying BEAKES to BRAKE VALVES (mechanically connected to the pedals), goes through COMMAND VALVES (anti-skid) but it is not mitigated. Then to the CHECK VALVES,and so to BRAKE ASSEMBLIES (3 disks 6 brake pads)
Maximum allowed for WORN OUT INDICATOR of brakes
1mm out
In case of simultaneous braking from front and rear cockpit, which one will be prioritized?
The stronger one
How does emergency braking work?
EMER BRAKE HANDLE sends hyd pressure directly to 2 CHECK VALVES that point fluid towards BRAKE ASSEMBLIES
Minimum pressure for braking action
70 bar
(But with a pressure of 50bar at least 10 applications of brakes should be granted)
Anti-skid system components
2 anti-skid switches (front and rear)
2 speed sensors
2 WOW MW
Anti-skid Control Box
2 Anti-skid command valves
With Anti-skid off, what happens to control box?
It is not energized. Therefore command valves stay open and hyd pressure is not mitigated from brakes application to brake assemblies
In the brake hydraulic line, where Anti-skid Command Valves are located?
In between of Brake Valves and Check Valves
NWS system components
2 push buttons
Steer light
Steering Control Box
MW consent
Intercepting valve
Steering actuator
Intercepting valve in the NWS system, where does intercept hydraulic pressure from?
From landing gear system line
(This is why if you pull the emergency extension you don’t have steering anymore)
When do you expect to have maximum temperature of hot brakes?
5 to 15 min after brakes application
In case of hot brakes how would you park the aircraft?
In the hammerhead, with wind blowing from the right
