Elevator Trim Indicator Bulb???
 

When I was under the pedestal, I noticed the elev. trim indicator had a fitting at the bottom for a flange-base bulb to illuminate it with the panel. Me, being OCD about all bulbs working, have spent an hour or more trying to figure what type bulb goes there. A 387 bulb is the right shape, but its flange base is only 5mm, whereas this bulb would be closer to 10mm at the base.

Parts catalog makes no mention of this bulb, only an "edge light assembly" which I assume includes this bulb. See photos from parts manual for reference.

There was no bulb in the socket, so if anyone can shed some light on this mystery bulb, it would be greatly appreciated!

My airplane is in annual right now. I'll ask my mechanic to look at the bulb and let me know what it is.

Rick

I determined it uses a 327, the same as many other bulbs in the panel. If its a push-to-test socket, its probably a 327.

It's not a push-to-test socket. It has a cap that holds a bulb which illuminates the trim position indicator when the panel lights are turned on.

I realize that my friend. But its the same bulb as the lights that are push-to-test.

These are available in LED as well
 

I switched all small bulbs to their equivalent LED.

Now the gear up/down lights cool to touch and never burn out.

Same with backlight bits

I THINK they were called T1-3/4 midget-flange 28 volt from dialight (digikey/amazon etc).

About $7 each

Good to know! Thank you!