Airspeed Safety Interlock

[Releew]

Hello All....

Looking for a part # and location of the Airspeed safety interlock.  I cannot find it anywhere in the Parts Manual.  Just recently in a Gear Retraction test we were able to raise the gear without flowing Air in the Pitot Tube.

Any information or guidance is always appreciated!

M20J MSE 1992

Rick

 

[PT20J]

There are two locations that I know of: My 1978 J had it mounted to the back of the airspeed indicator and my 1994 J has it mounted on a bracket forward of the airspeed indicator up high under the windshield. It’s a gold anodized disk about 2 inches in diameter. Inside is a diaphragm and a spring with a pitot connection on one side of the diaphragm and static on the other. Under increasing pitot pressure, the diaphragm moves against the spring and closes a couple of normally open microswitches. One is used for the gear. The other can be used for a flight timer and is often unused. If the problem is a bad microswitch, and the second one is unused, you can switch the gear to the spare. There is a procedure to test the switch in the Service Manual. 

Skip

[carusoam]

Skip covered all the details….

If that doesn’t work…. The big diaphragm switch can be OH’d…

There is a lot written about this thing…

Best regards,

-a-

[Releew]

Thank you!  I would have NEVER looked there!  

 

Rick