What is this Gauge?

[Rob]

I'm still on the hunt for the right 500A/B. Inside the gear well there is a pressure gauge. Just wondering what this gauge is measuring and what pressure it should be reading on the ground?

[donv]

It's been a long time since I've flown a 500, but I'm going to guess that is the nitrogen pressure for the emergency gear extension. At least that is what it would be in a Turbo Commander, and deep back in my memory I seem to recall the 500 having the same basic gear system.

[JimC]

Yes, it's nitrogen for the gear extension.

It's supposed to read 275-350 psi, aka the green arc. That one looks about right to me.

That's a clean looking gear well.

[Adam Frisch]

Yes, nitrogen.

Most have been modified with a Schrader valve, just like a tire valve, but some still have the older fitting where you have to connect the hose, pressures it and then with a tool turn the hex bolt to let Nitrogen in.

[Rob]

Thanks for the feedback. One of the aircraft I was looking at (not the one in the picture) read nearly zero on the gauge and I didn't think this was correct. I'm still looking!

[donv]

I wouldn't run away from an airplane because the nitrogen pressure was zero, especially if the airplane has been sitting a long time. But it might be an indication... I've had mine leak, and it was the valve where you connect the hose.