M20K Unknown Dash Light

[andrew]

I was looking at an M20K today and saw a blue indicator bulb between the AI and HSI. This isn't the first Mooney I've seen this bulb on so I was wondering if it might have been stock and what its purpose may have been. In this plane it was not connected to anything. Any ideas?

[Dave Marten]

Interesting. My guess based on color and location next to the HSI is a remote outer marker (blue) light. If it is wired hit the test switch on the marker beacon receiver panel and see if you get a light. Not a stock light on the 231 K models.

Or ask the owner.

[Marauder]

Low vacuum light? Does it ever light? Could be burned out. I have one like this but not in this exact location on my F.

[rgpilot]

I have one that indicates gps active.

[Bob]

Should show in the logs.  Have you checked yet?  Not on my K.

[xftrplt]

Seems obvious.

A sale at "K"mart.

[carusoam]

The light is to define the source that is feeding the HSI.

This is to minimize the surprise that would come from navigating to an ILS by GPS and forgetting to switch the source over from one NAV radio to the other.

This was used when the GPS was a different box than the NAV/COM.

And it's true, the old systems can be picked up at the blue light special price....but not until the KSN770 actually goes on sale.

Thanks for the review of modern aviation history...

Best regards,

-a-

[fantom]

 Correct...and it was original equipment in the early to mid 90's.

The light is to define the source that is feeding the HSI.

This is to minimize the surprise that would come from navigating to an ILS by GPS and forgetting to switch the source over from one NAV radio to the other.

This was used when the GPS was a different box than the NAV/COM.

 

[flyboy0681]

This is to minimize the surprise that would come from navigating to an ILS by GPS and forgetting to switch the source over from one NAV radio to the other.

 

Wish I had this light, I still have a problem remembering to switch over from GPS to VLOC.

[carusoam]

That's an important check list item for IFR safety...

Best regards,

-a-

[flyboy0681]

That's an important check list item for IFR safety...

Best regards,

-a-

 

The GPS automatically switches over from GPS to VLOC on an ILS, but when things get harried on a VOR approach I sometimes don't catch it until the intermediate fix. But I'm working on it.

[jlunseth]

Yeah, the problem is not switching from GPS to VLOC, which the 430/530 does automatically if the approach is activated and you have switched the localizer to be the primary nav frequency, it is that the unit is then left in VLOC.  So you land, park the plane, go flying days later and assume that the box is on GPS like it always is, until you can't get the GPS to work with the HSI properly and figure it out.

 

But I don't think that bulb can tell if the signal coming from the 430 is a GPS or VLOC signal, it is from the switching days and knows only if you have switched to NAV 1 as the source (say a VOR receiver) or NAV 2 (say your GPS).

[aviatoreb]

Does it light up if you have a good idea?

[Marauder]

Does it light up if you have a good idea?

 

 

Hardly. It lights up to remind you that you need to deposit more money in your bank account to cover your aviation addiction.

[andrew]

Interesting.  I suspect it was probably a LORAN light then.  This plane had a TI-9200 IFR en route LORAN installed by the factory, it seems likely the light was for that unit.

 

No, it no longer lights up.  The wiring to it is cut and tied off behind.  The light was probably just left in the panel to fill the hole.

[carusoam]

Same reason... Source between two different nav radios.

Best regards,

-a-

[Mooneymite]

Hardly. It lights up to remind you that you need to deposit more money in your bank account to cover your aviation addiction.

 

Nah....that light is always a red one.