Blue Light

[Duane Baker]

What is this blue light, it has never come on and the previous owner does not what it is for. 93 201

[mike_elliott]

Ill bet it is an annunciator that the HSI is receiving GPS source vs LOC source but could be wrong. 

[smwash02]

Mine is labeled "A/P SEL". I'm new to the plane haven't quite figured out when it comes on.

[Emmet]

Outer Marker ...?

[M20S Driver]

16 minutes ago, mike_elliott said:

Ill bet it is an annunciator that the HSI is receiving GPS source vs LOC source but could be wrong. 

That is exactly what it is on my plane.  There is tiny light bulb inside that I had to replace a couple of years ago.

[RogueOne]

WalMart Special alert.

[PT20J]

You might try looking through the 337s and logbooks to see what equipment has been removed to get a clue. My ‘94 J has a light (it’s amber on mine) in the same location labeled GPS ACTIVE. I think it was part of the original factory KLN 90 installation which was removed and replaced with a GNS 430W at the same time the Aspen PFD was added by the previous owner. Since the Aspen annunciates the nav source, any requirement for a separate indicator is eliminated  

Skip

[laytonl]

Mine lights up when the HSI is taking directions from the GPS signal from the GNS530W.  The light goes out when I switch to LOC. Lee

[kerry]

10 hours ago, RogueOne said:

WalMart Special alert.

Kmart is more accurate  

[carusoam]

I think I may know this one... 

It is an early 90s special...

Blue light... HSI is being fed guidance from the GPS...

No light... HSI is being fed by the other resource connected to it... or the light burned out.

Find the BK 20 pole, single throw, switch that operates it... GPS/VOR somewhere over on the right side of the panel near the other similar switch  Free/Slaved... also for the BK HSI...

The magic of the little blue light wore off about the time Garmin was building three receivers in one box and a color screen to tell what type of approach was being used...

 

PPI failure... the blue light needed a bulb... it was hard to find.  Jimmy @AAA arranged to have one installed at my local MSC after I got home...

The blue light is on all the time... expect if you haven’t seen the blue light in a while... it may have a dead bulb...

If you are a child of the magenta line... see what happens when you turn the blue light off... 

The plane still flys... but may follow a scalloped pattern between VOR stations...  

Expect that the light is next to the HSI for a reason... you fly for hours using the GPS... then switch over to another radio to set up for the ILS...  somewhere in there is a huge cognitive error waiting to occur...

So if you are waiting for the ILS to come active, and the blue light is on... that should ring a bell... sort of a back-up to your approach set-up procedures...

PP thoughts only, not a CFI...

Best regards,

-a-