CAS to TAS with your flight computer

1. Set pressure altitude in the window opposite the OAT in Celsius.

2. Without moving the computer’s scales, read TAS on the outer scale opposite to CAS.

If the aircraft is flying in excess of 300 kts, a larger uncorrected compressibility error rises.
Any conversion from CAS to TAS results in TAS higher than 300 kts a a correction has to be made using the compressibility factor or using the compressibility window in your flight computer.

Standard temperature FL100, 15 - 2 x 10 = -5º C. OAT = -5º + 10º = +5º C

Set the OAT against the PA, and opposite to TAS 150 and 105 read CAS 127 and 89 kts respectively. 127 - 89 = 38 kts