TruAirspeed vs xWind

TruAirspeed is a True Airspeed Calculator for the iPhone and iPad. It's a bit different from other true airspeed calculators, in which the pressure altitude is an input. This requires resetting the altimeter to the standard sea level pressure of 29.92"Hg to read the pressure altitude. With TruAirspeed, you input the indicated altitude and the Kollsman window's pressure setting — the app then calculates the pressure altitude, density altitude, true airspeed and mach number for you. The calculations involved take full account of compressibility effects, but not shock waves, so it's limited to subsonic, non-transonic flight only. You have a choice of units for inputs and results, and you may choose either a calculator-style keypad (top row: 7-8-9) or a telephone-style keypad (top row: 1-2-3). You may also set a correction factor for your bird's airspeed indicator/pitot-static system, if you know it (mine is 0.95).

xWind is an easy to use tool to assist pilots in evaluating wind conditions with respect to head, cross and tailwind limitations. Once setup, the xWind app provides all information in one single screen, requiring minimal user interaction during high workload phases of flight, displaying: - Current wind direction and speed - Runway course - Cross and head or tailwind components - Currently applied wind limits - 'Forbidden' wind angles based on the current wind speed - Maximum wind speed table based on current wind limits ​ Reference wind, runway course, as well as wind limits, can all be adjusted on the main screen by either dragging the wind arrow, course rose or wind limit lines. A settings button at the bottom presents a popup screen where both the units for wind speed (Kts or Mps) and the default values for wind limits can be specified. In addition to the general setting for wind speed units, the user can select the alternative units for only the current wind, wind components and maximum winds table by double tapping the wind display at the top of the main screen. When operating from a Kts country into Mps territory, this option allows to set the current wind and see the maximum allowed winds in Mps, based on limits that are still set in Kts. Or vice versa.... xWinds supports iOS darkmode.