Ray Allen POS-12 flap position sensor installation


I'm looking for installation recommendations (pictures) of Ray Allen POS-12 position sensor on a IV-P to display flap position on G3x. My first guess is to mount it someplace under the rear seat, attached to the flap bell crank. I have searched the site and only found one post. Any suggestions on how to, or how not to, are welcome.


rpastusek's picture



I used model airplane control linkage parts like Gordon P to connect a Ray Allen linear position indicator to the flap bellcrank. I bolted a small AL tab to the bellcrank to achieve the correct travel/throw length needed by the sensor. It’s worked without issues for 15 years now…

I’ve looked for a picture w/o success, but could remove my pressure controller to gain access/ take pix if that would help??

I have one that doesn't work,

I have one that doesn't work, if that info is useful to you.
I'll have to get to the airport to take some photos.
The builder attached it to the bellcrank.

When the flaps are physically at 15°, the flap indicator zips to full flaps.
I replaced the indicator in case that was the problem; nope.
I figured there was something wrong with the geometry
I have not yet figured out what will fix it but will be following your thread.

harrelson's picture

I save weight and money. I

I save weight and money. I look out the window. For takeoff I match 'em to the full deflection ailerons. For approach flaps I hold 'em down for 3 seconds (gets to the same position as takeoff flaps). Why would you need a flap indicator at all?





I suspect Bill does the same

I suspect Bill does the same as me at night - shine a flashlight out there to see where they are.

I have a very nice

I have a very nice installation - photos to follow

very simple and adjustable

Lancairmikees's picture

I'm kind of with Bill on this

I'm kind of with Bill on this one. I have a sensor connected to a GRT EFIS for display but in reality never look at it. I do have a AOA which gives me an audible "Flaps" at about 20 degrees deflection though. 

I wonder how the EFIS knows

I wonder how the EFIS knows the flaps are at 20...?!

Or perhaps the AOA is calibrated to that configuration?

Thanks to all for your input.

Thanks to all for your input.  I have included the pictures that are most representative of the responses I have received.

Pictures 1,2 and 3 show a version that also has a micro switch wired to the AOA to automatically change the AOA from "flaps up" to "flaps down" configuration.  The aluminum template was used to find the correct orientation and attach point to get the throw needed. The push rod on this installation was made from remote control airplane linkages. 

Picture A is from a different IV that shows that owners final location of the sensor and push rod to the bell crank.  The sensor can be mounted facing up or facing aft.  Dealers choice.

Other general comments I've received are 1) It is important that the throw of the sensor actuator is such that it does not bottom out on either end, 2) making the push rod length adjustable simplifies things



off-topic question; Ken in

off-topic question; Ken in pic 3, what is the black cylinder plumbed in with the 90° twist valve?



Sorry, I don't know what that cylinder is for.  Not my airplane. Maybe emergency gear extension???


rpastusek's picture



Thats my airplane-under construction. It’s a hi-flow fuel filter; one of two I removed before first flight—based on advice from Ed Smith, an expert in these matters. His specific words: “Never put an obstruction such as a filter in the inlet to a pump; after the pump is OK, but not before.”


Lancairmikees's picture

The EFIS is only a display of

The EFIS is only a display of relative position. The AOA is a separate unit connected to a dedicated micro switch that closes at 20 degrees and greater deflection