Hot Weather Operations
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Ambient temperature, be it hot or cold, has an effect on aircraft operations irrespective of the airport elevation. Whilst the combination of heat and high altitude, as discussed in the SKYbrary article Hot and High Operations, has a particularly detrimental impact on aviation, heat alone can also have substantial repercussions when considering safe and efficient aircraft operations. Extreme heat, common to many areas in Africa and the Middle East, is becoming increasingly more common, albeit for relatively short periods of time, in other areas of the world inclusive of Europe, Australia and North America.
Virtually all commercial pattern aircraft have a published environmental envelope. This envelope includes the maximum static temperature, by pressure altitude, at which operations are permissible. In June 2017, an outside air temperature of 120° Fahrenheit (49°C), in Phoenix Arizona, forced the cancellation of a number of Bombardier CRJ flights due to exceedance of the maximum operating temperature for that aircraft type.
Density Altitude is Pressure Altitude corrected for a non-standard temperature. The baseline for the International Standard Atmosphere (ISA) assumes sea level atmospheric pressure and temperature to be 1013.2 millibars and +15°C respectively. Under these conditions, Density Altitude and Pressure Altitude are essentially the same. Maintaining the pressure but increasing the temperature will increase the Density Altitude. The Density altitude increases by approximately 120 feet per degree above the ISA Standard temperature for the pressure altitude. A sea level aerodrome with a temperature of 45°C would have in a Density altitude of 3600 feet (120 x (45-15)). As aircraft performance is directly related to Density Altitude, temperatures above ISA can result in a substantial performance penalty.
Impact on Personnel
- Hot and High Operations
- Density Altitude
- Factors Affecting Aircraft Performance During Takeoff and Climb - from Aircraft Performance for ATCOs Toolkit.