Hot and High

Hot and high refers to operational conditions where high ambient temperatures and high airport elevation combine to reduce air density, significantly degrading aircraft performance. Lower air density means less lift from wings, less thrust from engines, and less effectiveness from propellers.

Effects of hot and high conditions include:

• Longer takeoff rolls and reduced climb rates
• Higher true airspeeds for the same indicated airspeed
• Reduced engine power output (especially for naturally aspirated piston engines)
• Higher landing speeds and longer landing distances

The combined effect is quantified as density altitude — the altitude at which the current air density would be found in a standard atmosphere. An airport at 5,000 feet elevation on a 40°C day may have a density altitude exceeding 9,000 feet.

Airports notorious for hot and high challenges include Addis Ababa (HAAB, 7,625 ft), Mexico City (MMMX, 7,316 ft), Bogotá (SKBO, 8,361 ft), Denver (KDEN, 5,431 ft), and many airports in the Middle East where surface temperatures routinely exceed 45°C.