Project 2 - Implement the Code for controlling the retraction and extension of Airplane’s landing gear
Actually an airplane has 3 gears for landing :
•
Nose Gear
•
Left Gear
•
Right Gear
There is a hydraulic pump which is exerting pressure to the
gears to bring it down or pull it up and that pump is
electrically driven.
Every leg of the gear has one limit switch
.Nose gear has
one extra Squat Switch to determine whether the airplane
is in ground or not.
Switch State
State of Gears
Limit Switch CLOSED
Gear is UP
Limit Switch OPENED
Gear is DOWN
Switch State
State of Airplane
Squat Switch CLOSED
Airplane is grounded and Gears
are locked
Squat Switch OPENED
Airplane is taking off / landing /
airborne
A direction valve is controlled by the software to allow the
hydraulic pressure to either raise or lower the landing gear
Status of Direction Valve
States of landing gear
Direction valve = Down
(Gear Down)(Parked at bay or Landed)
Direction valve = Up
Raising Gear(Taking Off)
Control of hydraulic pump for the
landing gear part is disabled
Gear Up(Airborne)
Direction valve = down
Lowering Gear(Landing)
Input for the Direction Valve
Pilot’s Lever State
Direction Valve State
Lever UP
Direction valve = Up
Lever Down
Direction valve = Down
Pilot’s Lever State
Light Status
Lever Rising Edge
Red
Lever Falling Edge
Every gear has one light. According to the state of the
gear,color of light is changing
Landing Gear State
Light Status
Gear is up
OFF
Gear is down
Green
Gear in transit(Raising or
Lowering)
Red
There is a possibility that the plane is about to take off and
an emergency comes where pilot has to abort the take off
•
When taking off,to ensure that its right time to raising the
gear,check for at least 4 seconds that squat switch is open
When the airplane is parked at the bay and nose gear is
down,then the nose gear is always experiencing a pressure
on it due to airplane weight,weight of luggage and weight
of passengers boarding on the airplane.Hydraulic
mechanism is monitoring the pressure exerted on the
nose gear and to neutralize that pressure its applying a
pressure on the opposite direction
Hydraulic Control can detect the rising edge and falling
edge of pilot’s lever
•
In case of Hydraulic system failure,there are two gas
pressurized springs by which gears can be extended
•
The case of failure of Squat Switch is ignored
Checking
before
Take off
Delay 3s
Gear
Down
Raising
Gear
Checking
before
Landing
Lowering
Gear
Pilot’s Lever Rising && Squat Switch
Open / Lights = Green
Squat Switch Close or Pilot’s Lever falling/
Lights = RED
Pilot’s Lever UP / Direction Valve = UP,
Lights = RED
Gear UP
Limit Switch Closed /
Lights OFF, Control for
landing gear disabled
Pilot’s Lever falling / Control enabled
,Lights = Red
Pilot’s Lever Down/ Direction Valve = DOWN
Pilot’s Lever Raising / Lights = RED
Pilot’s Lever Falling/ Lights = RED
Limit Switch Opened/
Lights = Green