Mystery Light Switches in Panel

PropFan

I cannot find a log book entry for installation of these variable light switches, which are clearly aftermarket for my 180C. Can someone please identify make and model? (By the way, what is a "Rad Light"? The second switch just seems to dim the panel lights.

jruhnke

Radio light dimmer?

bnolen

Same configuration in my Cherokee 140, though not aftermarket in the 74 model. The right wheel (rad light) dims the panel lighting. I don't think it has definite click like the left wheel when turned off, or way down.

PropFan

Jruhnke: Duh. That should have occurred to me.

Bnolen: my switches operate the same way, and you've confirmed my suspicion that these were OEM in later models.

78TARROW

If they're not OE on your aircraft, there should be an STC with a supplement that shows what they do specifically.

They are an OE option in my Arrow, with one located on either side of the switch cluster. The Panel Lights dimmer is on the right and has a definite click for 'OFF' and when 'ON' it automatically dims the gear and annunciator lights, sort of a nighttime setting. The Radio Lights dimmer is on the left and has a definite click for 'OFF' and when 'ON' it also powers the navigation lights and after market strobe on the tail fin. The wingtip strobes have a separate switch.

PropFan

Thanks, 78TArrow. The mystery deepens a little. I have pored over my log books several times, and I have an official set of 337s from the FAA, and there is no mention of installation of these switches. My mechanic confirmed yesterday that the Whelen control units for the rotating beacon and the nav/strobe lights (located in the aft fuselage behind the battery) are after-market installations as well, for which there is no log book entry or Form 337. I can't find anything in the Parts manual that indicates these are OEM for a 1965 180C, and I've never seen an "original" 180C panel with these switches. That's why I was hoping someone might be able to name the manufacturer, so I could look for some STC documentation.

So, it seems the "Panel Lights" label on the left is just a generic descriptor, and the "Nav Light" and "Rad Light" labels on the right describe the functionality of the left and right switches, respectively??

JoeB

PropFan wrote:

So, it seems the "Panel Lights" label on the left is just a generic descriptor, and the "Nav Light" and "Rad Light" labels on the right describe the functionality of the left and right switches, respectively??

In the 1980's-era Cherokees the "Panel Lights" switch turns on and adjusts brightness of the instrument lights. For the most part these are post lights which live behind the plastic overlay. The "Nav Light/Rad Light" switch does two things: It turns the Navigation Lights out on the wingtip/tail on/off, and it adjusts the brightness of any lights in your radio stack. Modern electronics, with all its glowing displays, doesn't have much need for a light in the radio stack. But older radios which turned a physical card to show you which freq you'd selected needed a light for nighttime use.

Your installation looks exactly like what one would find in an 80's-era Cherokee, down to the switch labels. (I can't really speak for earlier or later as all the Cherokees I've flown have been that vintage.) I'd hazard a guess that if you pulled the switches out you'd find Piper part numbers on them. Somewhere in the past someone decided to "modernize" your aircraft.

PropFan

That's helpful, Joe. Thanks.

78TARROW

One you get the info sorted, I'd recommend getting an I&A to help generate a 337 and make logbook entries. I'd then send the 337 off to the FAA. Truth be told, there's no way an acft should 'pass' an annual if the configuration doesn't match the records. Happens all the time though.

PropFan

Good suggestion. The W&B probably needs to be re-done, too, because of the aftermarket strobe nav/strobe controls installed in the fuselage. That will be a challenge. Maybe I should just get the plane re-weighed while I'm at it.