Reading nearly 20k higher airspeed at cruise than actual on my RV-8. Need help determining where problem may be and what to do. Thx, Bill
Had a similar problem in my RV7. A static leak will also cause the altimeter to read high compared to your GPS altitude. John Adams
They should indeed be close on the ground at the location the altimeter setting is for. That is one reason we use altimeter settings. The other big reason is so that aircraft in the same area will be flying at corresponding, not true, altitudes. In other words, everyone that shows 8,500 feet, in the same area, will be at about the same altitude.But assuming your Kollsman window has been adjusted for local pressure, they should be very close.