Check on Retraction Interlock between Landing Gear...
1.Equipment Needed
A main landing gear restraining panel,an avometer,a hydraulic jack and a 28V ground DC power source.
2.Preparations
a)Supply power to the helicopter.
b)Tilt the instrument panel backward.
c)Connect an avometer between binding post 1A of landing gear control switch 1G and the floor of the helicopter.
3.Testing Procedures
Note:The hydraulic system shall not run with excessive load during the test.Check if the landing gear control switch is secured by safety pins.
a)Install the main landing gear restraining panel on left main landing gear.
b)Jack the helicopter.
c)Check:
·If the shock-absorbing legs of nose landing gear and right main landing gear are extended.
·If nose landing gear is centered and locked.
d)Check if the reading of the avometer is zero.
e)Lower down the helicopter.
f)Remove the main landing gear restraining panel from left main landing gear and install the panel on right main landing gear.
g)Jack the helicopter.
h)Check:
·If the shock-absorbing legs of nose landing gear and left main landing gear are extended.
·If nose landing gear is centered and locked.
i)Check if the reading of the avometer is zero.
j)Lower down the helicopter.
k)Remove the main landing gear restraining panel from right main landing gear.
l)Jack the helicopter.
m)Check if all shock-absorbing legs are extended.
n)Turn the wheels of nose landing gear so that they deviate from the symmetrical center line by more than 2 degrees.
o)Check if the reading of the avometer is zero.
p)Center and lock nose landing gear and put landing gear switch at“EMERG”position.
q)Check if the reading of the avometer is zero.
r)Center and lock nose landing gear and lower the helicopter down on the ground.
s)Make sure rocker arm(2)keeps clear of contactor(1)of the microswitch.
4.Calibrating Procedures
a)If rocker arm(2)touches contactor(1)of the microswitch,re-adjust the microswitch.
b)If the reading of the avometer is not as zero as stipulated in steps 3d),3i)and 3o),re-adjust related microswitches.
c)Conduct the test again after the microswitch(es)is(are)re-adjusted.
d)If the reading of the avometer is still not as zero,replace the microswitch.
e)Conduct the test on newly-replaced microswitch(es).
f)If the reading of the avometer is not as zero as is stipulated in step 3q),replace the emergency switch of the landing gear.
5.Finishing Touches
a)Disconnect and remove the avometer.
b)Lower down and lock the instrument panel.
c)Unplug the GPU.
Microswitch of Landing Gear