GS-PAPER- III/ Environment and Ecology

Context

• Recently, high temperatures at elevated altitudes are causing disruptions in flight operations to and from Leh, which is located around 10,700 feet above sea level.

How Do Aircraft Fly? 

1. Design of Aircraft Wings: 

• Aircraft wings are designed with the top surface more curved than the bottom. 
• As the aircraft moves, air flows faster over the top of the wings than beneath them.

2. Bernoulli’s Principle: 

• This principle asserts that in a horizontal fluid flow, areas with higher fluid speed will experience lower pressure compared to areas with slower fluid speed.
• The increased airspeed over the wings creates a lower pressure above the wings relative to the pressure below them.
• This difference in pressure produces a force called lift, which aids in the aircraft’s take-off. 

High Temperatures and Impact on Aircraft’s Flight: 

1.Thinning of Air and Loss of Required Lift: 

• Higher temperatures cause to the expansion and reduction in density of air, which means there are fewer air molecules under an aircraft’s wings to produce adequate lift.
• Experts in atmospheric science indicate that aircraft experience a decrease of approximately 1% in lift for every 3°C rise in temperature.

2. Impact on Engine Performance: 

• Thinner air decreases the amount of oxygen available for combustion, which in turn reduces thrust.
• In hotter conditions, planes require longer runways and more powerful engines to achieve take-off.
• For example, a runway that is 6,500 feet long at 20°C would need to be extended to 8,200 feet at 40°C. In extremely high temperatures, take-off can even become unfeasible.

Landing Becomes More Challenging: 

• Thinner air affects landing by reducing the effectiveness of reverse thrust, which is used to slow down the aircraft. 

Situation at Leh: 

• These issues are particularly felt in airports located at higher altitudes, like Leh, where the air is already thin and runways are often shorter. 

Role of Global Warming: 

1.Global Temperature Rise: 

• Since 1880, the global average temperature has risen by at least 1.1°C. 
• In India, annual mean temperatures have increased by about 0.7°C since 1900. 

2. Impact on Air Travel: 

• Higher temperatures are already disrupting air travel. 
• A 2020 study on Greek airports found that the warming trend reduced the maximum take-off weight of the Airbus A320 by 127 kg per year, impacting lift and thrust. 
• A 2023 study “Decreased Aircraft Take- off  performance under Global Warming , predicted that rising temperatures will increase the take-off distance for a Boeing 737–800 by 6% on average by 2071-2080, requiring an additional 113-222 meters at low-altitude airports. 

3.Adaptation Measures: 

• In the short term, airports must adapt by scheduling flights during cooler times, extending runways, and reducing take-off weights. 
• Long-term solutions involve significantly reducing fossil fuel consumption to mitigate global warming.

Conclusion:

High temperatures and low air density significantly impact aircraft performance. As temperature rise, air becomes less dense, reducing the amount of oxygen available for combustion and thereby decreasing thrust. This necessitates longer runways and more powerful engines for take-off. In extreme heat, the reduced air density can make it difficult or even impossible for aircraft to achieve the required lift, leading to operational challenges and potential delays. Consequently, managing these conditions is crucial for ensuring safe and efficient flight operations.

Source – Indian Express