FlightAltCheck is an app created to help pilots understand and calculate cold temperature altitude corrections for barometric altimeters.
Most aviation authorities’ procedures and regulations require or recommend pilots to apply corrections to minimum instrument approach altitudes during periods of very cold weather conditions, or cold weather conditions in combination with terrain.
The standard reference for these corrections is the International Civil Aviation Organization (ICAO) document PANS OPS Doc 8168.
A correctly calibrated pressure altimeter indicates true altitude above mean sea level (MSL) only when operating within the International Standard Atmosphere (ISA) parameters of pressure and temperature.
The non-standard pressure conditions are corrected by applying the correct local area altimeter setting (QNH), but temperature differences from ISA are not usually considered.
The conditions that may endanger aviation safety occur when temperatures are colder than ISA, as true altitudes could be lower than indicated altitudes causing the risk of inadequate obstacle clearance.
FlightAltCheck can be used to determine altitude corrections using the three different formulas recommended by ICAO in PANS OPS Doc 8168.
The full version of FlightAltCheck allows saving an unlimited number of procedures.