The International Cessna^® 170 Association

I just ordered a battery switch replacement part for my 170A. The first part Aircraft Spruce sent me was bagged wrong (part # on the part didn't match the part # on the bag). They were great and sent me the correctly numbered part. Because I've already recieved a wrong part I was very careful in looking at the just recieved part ... here's the question.

Isn't the switch supposed to be "Off" in the centered position? My battery switch is the left switch on the piano keyboard, and the part from the IPC is AN3027-2. Some of the other switches to the right of it (in the IPC) are "-22" for their part number. The switch Aircraft Spruce sent me is a two position switch with no centered position. If the "off" position is not in the center, won't the piano switch be either "up" or "down" position when it's off? Instead of centered like the rest of the keyboard switches?

Anyone have any experience here?

Yes the switch is suppposed to be "off" in the center position. Interesting, the '52 B has the same panel layout and piano key switches as the "A", yet the part numbers appear to be different. The master switch for the '52 is AN3027-1, not -2.

On the '52 all of the piano key switches including the master are actually the same; AN3027-1 three position (Up-on, Down-on, Center-off), however their movement is limited by switch limit clips that are kind of "J" shaped. When the piano key is pushed down it "cams" against the switch throwing it up. The clips prevent this from happening when lifting the paino key "Up".

The only time (on the '52 anyway) that the factory used both positions of a single switch was if the aircraft had the Stewart Warner heater installed. In that case, Up was for "Fan" which primed the heater and Down was for turning the heater "On". Off was neutral.

It would be a fairly simple exercise to make use of the three position switches if you wanted to, say split the Taxi light/landing light function or Nav light/strobe function.

My ragwing was fitted with a leading edge landing/taxi light assembly, in leiu of the standard fold-down landing light. One of the piano-key switches is rigged for up-landing light/center-off/down-taxi light.
BTW, my 1948 IPC calls out two different Cutler-Hammer switches, p/n 8800K-7 & 8800K-5. Looks like the master is the -5 and the other four are the -7. Also calls out "clip-switch limit", p/n 0411889, quantity four.

Eric

I'm gonna have to get me the 170 & 170A IPCs. I *thought* the piano key switches were the same, yet it appears there are three different sets of p/ns for the switches dending on the model... strange.

Doug,
Thanks, I guess I'll have to order the AN 3027-1 ... this time I hope to get it right. 'preciate the help