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flap asymetric switches


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Hi every one as we all know that there is asymmetric switches in Flap system .switches are installed 120 degree apart no of switches are 3 .asymmetric condition of 3 to 5 deg will stop the flap movement can any body tell plz if first switch is not working or is us then what will happen is the difference will be more and kindly plz any refferance book .

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If we assume that one switch has failed, there are two ways to look at it.

IF one flap has stopped moving completely AND has a failed switch, the other flap will continue to operate until it gets to the set position of the flap handle.

IF both flaps are still moving, just not in asymmetry AND have a failed switch, they will stop at the next set of switches.

A left wing switch and a right wing switch MUST activate in series to energize the flap emergency brake valve and hydraulically set the asymmetry brakes.

The flap torque tube moves 32 revolutions per 1 revolution of the asymmetry switch cam.  So under normal setting of the asymmetry brakes, 3-5 percent difference in flaps is approximately 10 revolutions of the flap torque tube.

Under the condition that both flaps are moving just not in symmetry and you have a failed switch, the flaps would rotate to next set of switches.  So they would get 6-10 percent difference before setting.

If you look at the diagram I posted, imagine a flap torque tube snaps on one side exactly where the diagram is drawn. There is no way ever that the asymmetry system could set if it had a failed switch because the power must pass through to the other set of switches.

Hope that helps




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