Inverted Airspeed calculator
-

Test: PA = 10,000, OAT = -20°C, IAS = 140
Result: 157
Actual: 158 -
Okay maybe I don’t get how this works. Today I was flying at 6500ft with +20C so I aligned the 6.5 position below the +20 marker (on the left side) and the value I was reading on the bottom part was way more than what the GTN750 was telling me. So I aligned it below the -20 marker and there it was perfectly accurate.
-
What was your indicated speed, and what did the GNS report for your TAS? Also, it shouldn't make that much of a difference, but the altitude you enter it not necessarily the altitude displayed on your altimeter. You need to set your altimeter to 29.92" to obtain your pressure altitude, and then enter that on the TAS calculator.
-
Okay maybe I don’t get how this works. Today I was flying at 6500ft with +20C so I aligned the 6.5 position below the +20 marker (on the left side) and the value I was reading on the bottom part was way more than what the GTN750 was telling me. So I aligned it below the -20 marker and there it was perfectly accurate.