Density Altitude and ISA Deviation Calculator

WARNING: The app is intended only as an in-flight aid and should not be used as a primary information source. If the app contains a barometric altimeter, it will not function in a pressurized aircraft and should not be used in a pressurized aircraft. Density Altitude and ISA Deviation Calculator is a Connect IQ Aviation app for pilots who want a fast, practical way to assess atmospheric conditions directly on their Garmin watch. The app calculates density altitude, pressure altitude, and ISA deviation from pilot-entered values such as field elevation, outside air temperature, and QNH. Temperature is displayed in the unit configured on the watch. The QNH unit can be selected in the app settings - hPa/mbar, inHg, or mmHg - because Connect IQ does not give apps access to the watch's own pressure unit setting. On startup, the calculator can initialize field elevation from the watch altimeter, estimate QNH from the built-in barometer, and read outside air temperature from the connected weather service. These values provide a convenient starting point and can be adjusted manually before flight. It is designed for quick use before flight, during planning, or as a cross-check at the airfield - for general aviation pilots, flight instructors, and aviation enthusiasts. Key features: - Density altitude, pressure altitude, and ISA deviation - Selectable QNH unit: Auto, hPa/mbar, inHg, or mmHg - Elevation, QNH, and OAT prefilled from altimeter, barometer, and weather service - Simple pilot-focused input workflow - Button and touchscreen operation ===================================== User Guide Density Altitude and ISA Deviation Calculator calculates Density Altitude (DA) and Pressure Altitude (PA) from QNH, outside air temperature, and field elevation. It is for reference only - always use POH/AFM and current METAR/ATIS for flight planning. Initialization on startup On startup, field elevation is read from the watch altimeter, QNH is estimated from the barometer, and OAT is loaded from the connected weather service. These values do not update continuously - adjust them manually to current METAR/ATIS before use. Display The large center value shows Density Altitude. The active input field shows its current step size next to its name, for example QNH +-1. The color indicates ISA deviation: warm color = above ISA, cool color = below ISA, white = ISA standard. The two dots at the bottom of the screen indicate the current page. Button controls Press SELECT to switch between QNH, OAT, and ELEV. Use UP and DOWN to change the active value. Long press UP (MENU) to open the settings. Press BACK to exit. Touch controls Tap - or + to decrease or increase the active value. Tap and hold - or + for larger steps. Tap an input field to switch to the next one; tap and hold an input field to toggle between fine and coarse steps. Settings Long press UP (the standard menu gesture), swipe left, or tap the dots at the bottom of the screen to open the settings menu. Under QNH Unit you can select Auto, hPa/mbar, inHg, or mmHg. Coarse Steps switches between fine and coarse step sizes. Auto derives the unit from the elevation unit configured on the watch (meters = hPa, feet = inHg). Please note that the pressure unit set under the watch's aviation settings is not available to Connect IQ apps, so it has to be selected here separately. Both settings are saved and remain active after restarting the app. Swipe right or press BACK to return. Step sizes (fine / coarse) QNH: 1 hPa, 0.01 inHg, or 1 mmHg / 5 hPa, 0.05 inHg, or 5 mmHg OAT: 1 deg / 5 deg ELEV: 10 ft / 100 ft

Fix: DOWN button no longer opens the settings On watches with physical buttons, pressing DOWN opened the settings screen instead of decreasing the active value. The settings were reachable by swiping left, and on Connect IQ the DOWN button produces the same "next page" event as a left swipe - so the button was swallowed by the settings screen. The settings now open with the standard menu gesture: a long press on UP (MENU). Swiping left and tapping the dots at the bottom of the screen still work as before. UP and DOWN again do nothing but change the selected value. Also new: - The active input field now shows its current step size next to its name (for example QNH +-0.01) - Tap and hold an input field to toggle between fine and coarse steps - The fine/coarse setting is also available in the settings menu (Coarse Steps) and is now saved across restarts