What is the minimum ambient temperature approved for takeoff?

The minimum ambient temperature approved for takeoff is -40°C. This is primarily determined by the aircraft's performance capabilities and the manufacturer's specifications, which take into account factors such as engine functionality, fuel flow, and overall aircraft performance during low-temperature operations. Operating an aircraft at temperatures lower than this approved limit can lead to complications in engine performance, particularly issues with fuel viscosity and potential icing on critical components. Thus, -40°C is the threshold set to ensure that the aircraft can operate safely and effectively without risking operational hazards associated with extreme cold conditions.