It can be a disconcerting thought to realize how high temperatures can, and do, compromise the optimum performance of an aircraft. When high altitudes are coupled with very hot temperatures, conditions can become problematic. This is, particularly, true for low-performance airplanes which can experience problems maintaining a rate of climb that would be required to clear surrounding terrain.
Here, we will cover some vital aspects of the impact of heat on flying and what novice pilots, especially, should be aware of.
Heat Has the Power to Ground Planes
As mentioned, high altitude locations and high temperatures do not mix well and can damage a plane’s internal components, contributing to engine failure. Additionally, when fuel becomes over-heated, a mew set of problems arise. During extremely hot weather, the following realities should be taken very seriously:
*** The fuel-air mixture becomes reduced; and the horsepower out-put of the engines decreases.
*** The propeller develops reduced thrust since the blades (as airfoils) become less efficient in thinner air.
*** The wings develop reduced lift capability due to the thinner air exerting less force on the airfoils.
*** Increased take-off distance is required, climb performance is minimized, and in some instances, climb performance may not be possible, at all. Needless to say, when climb performance is compromised, aircraft taking off may not be able to clear surrounding hills or towers.
And the Top Temperature A Plane Can Fly In Is….
When air becomes too thin to provide adequate take off, canceled flights are the frustrating end-result. Case in point: during the summer of 2013, a heat wave engulfed Phoenix, Arizona; and temperatures reached 119 degrees Fahrenheit causing eighteen US Airways flights to be canceled. Interestingly, those planes were certified to take off in temperatures up to 118 degrees – one degree of heat left planes on the ground! With that being said, more massive planes for Boeing and Airbus can handle temperatures up to 126 degrees and 127 degrees, respectively. Recently, during June 2017, 40 flights that were due to take off from Phoenix – most of them American Airlines — were canceled due to heat extremes.
According to 30-year-veteran pilot, Patrick Smith, who authored the book, Cockpit Confidential, extreme heat will result in fewer air particles moving across the wings; and it is these reduced air particles that would, likely, be unable to meet the demands of contributing to the plane’s lift. Lift not only allows planes to take off, but permits planes to stay in the air, as well. Smith goes on to mention that a plane’s brakes and machinery can overheat in extreme temperatures, with results that would be, predictably, catastrophic.
Interestingly, at Dubai International Airport and other Persian Gulf airports, many flights arrive late at night or early in the morning to take advantage of cooler temps. In this part of the world, airlines also use larger planes that are not as affected by high heat. After it’s all said and done, it is not only a plane’s internal components that must be taken into consideration with blistering heat but, also, a plane’s ability to experience lift which is dictated by some fascinating aerodynamics.