Leh flights cancelled due to high heat: How extreme temperatures impact flying

A dozen flights have been cancelled in Leh since Saturday (July 27) owing to bristling heat. The hot temperatures have made it difficult for airlines to operate flights in the cold desert.

At least 12 flights have been cancelled by IndiGo and SpiceJet since last weekend scheduled around noon as temperatures in Leh jumped to 36 degrees Celsius.

On Monday (July 29), Indigo took to X, saying “high ground temperatures and runway restrictions” have led to the cancellation of all flights.

“This is probably the first time that airline flights have been cancelled because of high temperatures. Last year, the temperature was not so high as to affect flights,” an official from Leh airport told Times of India.

How do hot temperatures affect flight operations? Let’s understand.

Hot weather disrupts Leh flights

Leh, which is at an altitude of 11,000 ft, is known for its extreme cold. In winter, the temperatures could fall as low as -20 degrees Celsius.

Leh’s Kushok Bakula Rimpochee Airport is situated at 10,682 ft above mean sea level.

The air density is lower at high altitudes, with the rise in temperature further plunging the density.

This means that the flight engine needs to produce a greater thrust and lift to operate. However, this could increase the aircraft’s operational capabilities, making it unsafe to fly.

How extreme heat impacts flights

Climate change is making flying tough. Extreme heat not only impacts the human body but also makes flight operations more difficult.

It might be surprising but hot temperatures cause more flight delays than winter weather.

David Ryan, an assistant professor of safety science at Embry-Riddle Aeronautical University’s Prescott campus, told USA TODAY that hot air is less dense than cold air, meaning planes have less lift when temperatures soar due to fewer air molecules.

This makes it tougher for them to take off and stay afloat.

“Airplanes perform better aerodynamically at cool temperatures, when the air is denser,” Patrick Smith, a pilot, was quoted as saying by NBC News.

Extreme temperatures decrease the thrust of aircraft engines, with the plane sometimes needing longer runways for liftoff and achieve altitude.

As the atmosphere becomes hot, air expands, becoming less dense. This affects planes’ ability to be airborne, meaning they will need more runway space and less cargo to get in the air, as per a National Geographic article.

Ryan told USA TODAY, “The hotter it is, the longer the takeoff length, and the heavier it is, the longer the takeoff length.”

When temperatures surge unexpectedly, planes may burn off fuel on the runway to shed weight, as per the NBC News report.

As Bloomberg noted, airlines would often delay flights or unload passengers and luggage to reduce weight when mercury soars. This can trigger schedule disruptions, with flyers sometimes trapped for hours inside the sweltering aircraft.

According to Robert Thomas, an assistant professor in the aeronautical science department at Embry‑Riddle’s Daytona Beach campus, there is no fixed temperature to know when it is too hot to fly. Pilots have to consider a slew of factors, such as temperature, elevation and winds to ascertain if the aircraft can perform or not, reported USA TODAY.

The extreme heat problem affects airports with short runways more as flights do not get enough space to gain momentum to take off.

The hot temperatures also pose mechanical challenges. “Engines also are subject to internal temperature limits beyond which operation isn’t permitted, and when it’s really hot outside these limits are easier to exceed. I expect it to happen more frequently as climate change causes more extreme weather events, including extreme heat waves,” Smith told NBC News.

High heat also affects airline workers. As per the National Geographic report, tarmac emits a huge amount of heat, which on the hottest days could be compared to that generated by automobiles. This can make the job of airline staff, including flight attendants, “miserable and dangerous”.

Climate change and air travel

Jet travel causes an estimated 3.5 per cent of climate change by humans. However, it is itself being impacted by climate change.

Several reports of extreme turbulence have come to light in recent years.

Paul D Williams, a professor of atmospheric science at the University of Reading who studies turbulence and climate change, told National Geographic that turbulence incidents have become common due to climate change.

Climate change is making some flights longer. Intense storms affecting planes have also been reported. Flooded runways are another stark example of climate change.

As earth becomes warmer, these incidents are only likely to increase.

With inputs from agencies