"Roy Smith" wrote in message ...

Our Arrow has a similar sort of system which works off a 2nd pitot. I
don't see any such 2nd pitot on this plane, so I don't know where it
gets its information from. I could see it having some interconnection
to the throttle knob so it can estimate the MP (and the POH hints at
this), but it also appears to work off airspeed. I can't imagine it
having a mechanical pickup off the ASI.

The description I have is as follows:


Basically, there's an extra microswitch on the throttle control to sense the power setting and two pressure switches plumbed into
the pitot line. When the system senses a) a power setting below about 18" MP and, b) an airspeed below 120 mph, the circuit closes
and the gear is automatically extended. The system can also work to prevent gear retraction at full throttle and less than about 90
mph.