On Tuesday, May 5, 2015 at 9:26:23 AM UTC-4, Papa3 wrote:
I see a couple of old threads suggesting that Winter ASIs need to go back to Germany for repair and recalibration. One of the ASIs in our Grob 103 is reading 8-10kts low vs two known good units. Anyone had any luck with a shop in the US? Otherwise, it's off the the Fatherland with this one...

Yeah, I know, five years too late. I'll respond here, in the event that some future friend has this problem, too.

Keystone Instruments in Lockhaven, PA will fix any Winter airspeed indicators without having to ship them over the ocean to the Fatherland.

I'm not sure if it's not much cheaper than buying a new instrument, though.