Originally Posted by Twin Wasp

So you're saying if you're going to MDW and Chicago Approach says the "MDW atimeter is missing, the ORD altimeter is 29.92, descend and maintain 5000" you'd go ahead and later shoot the approach to MDW even though there is no mention of using the ORD altimeter on the MDW plate? Back in my 135 days we had a wavier to use airport's WX ob at a close by airport but we had to go through the NWS to find the variation in altimeter settings over distance and apply a correction. In effect doing what NACA/TERPS does when they publish the ball note for using another airport's altimeter.