Research&Report
How Rain, Snow and Hail Affect Aircraft Jet Engines
The modern aviation industry continues to evolve to ensure aircraft can fly safely in all weather conditions. Jet engines, considered the heart of aviation, are complex engineering products that work by ingesting tons of air per second. These engines inevitably encounter various types of precipitation such as rain, snow, and hail, which can affect motor performance in various ways. This article examines the effects of precipitation on jet engines, safety measures taken in engine design, and practical applications in airline operations.
Basic Operating Principles of Jet Engines
Jet engines are machines that produce thrust by ejecting high-pressure, hot gases backward, created by burning fuel in the combustion chamber. The engine first draws in and compresses air, then mixes this compressed air with fuel and burns it, and finally expels the combustion gases at high speed. During this process, the engine processes thousands of kilograms of air per second and reaches temperatures exceeding 1,500°C in the combustion chamber.
Effects of Rain on Jet Engines
Rain Ingestion Under Normal Conditions
Jet engines are manufactured with consideration for encountering heavy rainfall during the design phase. In light to moderate rain conditions, engines can largely maintain their normal performance. When water droplets enter the engine, they rapidly evaporate due to high temperatures and are processed by the system.
However, rain affects engine performance in several ways. The presence of water vapor can reduce combustion efficiency by altering the fuel-air ratio in the combustion chamber. Additionally, the cooling effect of rain can cause a slight decrease in power output by lowering the gas temperature inside the engine.
Extreme Rain and Hazardous Situations
During severe storms, heavy rain ingestion can lead to serious problems. Excessive amounts of water absorbed by the engine can significantly impede the combustion process. The most critical situation is “flameout,” which means the complete cessation of combustion. This occurs when heat inside the engine is rapidly absorbed by water, extinguishing the flame source.
Historical records show incidents where the combination of heavy rain and hail led to engine flameouts. In such situations, pilots may attempt to restart the engines but may be forced to shut them down again due to overheating risks. This situation can create critical scenarios requiring emergency landing.
Effects of Snow and Ice
Snow Ingestion and Problems
Snow crystals pose a different threat than raindrops. As snow particles enter the engine, they melt due to the heat inside the engine and turn into liquid water. This process can lay the groundwork for ice formation in some parts of the engine. Icing can occur particularly in the engine intake area and on compressor blades.
Icing affects engine performance in several ways. First, ice accumulation reduces engine efficiency by obstructing airflow. Second, the breaking off of large ice chunks and their entry deeper into the engine can cause flameout by disrupting the combustion process.
Anti-Icing Systems
Modern jet engines are equipped with various systems to prevent icing. Anti-icing systems prevent ice formation by heating critical engine components. Typically, hot air taken from the compressor is circulated around the engine casing to heat surfaces at risk of icing.
At airports on snowy days, crews can melt accumulated ice by running engines intermittently. This procedure is critically important especially in conditions of freezing rain, freezing fog, or heavy snow.
Hail and High-Risk Situations
Structural Effects of Hail
Hail is one of the most dangerous types of precipitation for jet engines. Since hailstones are hard and dense ice masses, they can cause significant mechanical damage to engines. Large hailstones can deform compressor blades, damage turbine blades, and create cracks in the engine casing.
Hail ingestion can cause sudden drops in engine performance. Damage to compressor blades reduces airflow and compression ratio, decreasing engine power. Additionally, damaged blades create vibration problems that can lead to complete engine failure.
Windscreen Damage and Other Hazards
Hail affects not only engines but also other critical aircraft components. Cockpit windscreen shattering is one of the common consequences of hail exposure. Obstruction of pilot visibility seriously jeopardizes flight safety. Additionally, wings, radar systems, and other external surfaces can also be damaged by hail.
Certification and Testing Processes
Engine Approval Tests
Jet engines undergo very comprehensive testing processes before entering service. Among these tests, rain, snow, and hail ingestion simulations occupy an important place. The Federal Aviation Administration (FAA) and other regulatory bodies establish strict standards to ensure engines can operate safely in certain weather conditions.
In ice ingestion tests, large ice chunks are introduced into the engine to evaluate the effect of icing on performance. These tests verify that anti-icing systems work as expected. Additionally, ingestion of other foreign materials such as volcanic ash is also tested.
NASA and Research Efforts
NASA Glenn Research Center plays a pioneering role in testing jet engines in ice crystal environments. In recent years, significant research has been conducted on the Ice Crystal Icing (ICI) phenomenon that occurs near large convective systems at high altitudes. This phenomenon has caused more than 150 engine power loss and damage incidents over the past twenty years.
Scientists, engineers, aviation regulators, and airlines are collaborating internationally to better understand the relevant meteorological processes, solve critical engineering questions, and develop new certification standards. These efforts aim to make future engine designs safer and more durable.
Operational Measures and Procedures
Pilot Training and Awareness
Pilots receive comprehensive training on encountering adverse weather conditions. Skills such as avoiding storm systems, radar interpretation, and detecting engine performance abnormalities are critical components of pilot training. Emergency procedures cover scenarios such as engine restart in case of flameout.
Weather Monitoring and Route Planning
Modern aircraft are equipped with advanced weather radars and real-time meteorological data systems. Pilots and flight planners use these tools to avoid severe storms and systems containing hail. Air traffic control enhances safety by providing aircraft with alternative routes that bypass hazardous weather conditions.
Maintenance and Inspection
After flying in rainy conditions, engines are carefully inspected. Damage to compressor blades, oil leaks, and signs of abnormal vibration are checked. Regular maintenance programs ensure that anti-icing systems are working properly and engine components are in good condition.
Future Technologies and Developments
Advanced Materials
Engine manufacturers are developing composite materials and advanced alloys that are more impact-resistant. These materials provide greater resistance to hail damage while also offering the advantage of lightness. Ceramic-coated turbine blades better withstand extreme temperatures and reduce icing risk.
Smart Sensors and Monitoring Systems
Artificial intelligence and machine learning technologies are revolutionizing engine health monitoring systems. Real-time sensors detect even the smallest deviations in engine performance, enabling early detection of potential problems. Predictive maintenance systems allow intervention before failures occur.
Improved Anti-Icing Systems
Next-generation jet engines are being designed with more efficient and reliable anti-icing systems. Electrothermal anti-icing systems offer more precise control compared to traditional hot air systems. Hydrophilic and hydrophobic coatings minimize water and ice formation by preventing accumulation on engine surfaces.
Rain, snow, and hail pose significant operational challenges for jet engines. While engines can generally operate safely in light precipitation conditions, excessive precipitation intensity can lead to critical situations such as power loss and even flameout. Hail poses a special threat due to the risk of mechanical damage and can affect multiple aircraft systems.
The modern aviation industry minimizes these risks through comprehensive testing processes, advanced engine designs, and effective operational procedures. Anti-icing systems, durable materials, and advanced weather monitoring tools enhance flight safety. Pilot training and awareness form the foundation for avoiding hazardous situations and dealing with emergencies.
In the future, smarter monitoring systems, advanced materials, and innovative anti-icing technologies will further increase the resilience of jet engines against adverse weather conditions. Continuous research and development efforts maintain aviation safety at the highest level and enable passengers to travel safely in all weather conditions.
References
- Aerospaceweb.org. (2024). “Effect of Rain & Snow on Jet Engines.” Retrieved from: https://aerospaceweb.org/question/propulsion/q0293.shtml
- Simple Flying. (2024, August 19). “How Does Precipitation Affect Jet Engines?” Retrieved from: https://simpleflying.com/how-does-precipitation-affect-jet-engines/
- Aviation Stack Exchange. (2024). “How does a jet engine handle suddenly entering a lot of rain?” Retrieved from: https://aviation.stackexchange.com
- Mondortiz. (2024, January 31). “How Jet Engines Handle Rain And Hail While Flying.” Retrieved from: https://mondortiz.com/how-jet-engines-handle-rain-and-hail-while-flying/
- Jet Parts 360. (2024). “How does a jet engine work in the rain?” Retrieved from: https://www.jetparts360.com/blog/how-does-a-jet-engine-work-in-the-rain/
- NASA Technical Reports Server. (2013, August 14). “Effect of heavy rain on aviation engines.” NTRS.
- Planenerd. (2025, March 16). “How Are Jet Engines Tested?” Retrieved from: https://planenerd.com/how-are-jet-engines-tested/
- NASA. (2023, August 24). “NASA Glenn Tests Aircraft Engines in an Ice Crystal Environment.” Retrieved from: https://www.nasa.gov/aeronautics/
- PMC (PubMed Central). (2024). “Detecting Clouds Associated with Jet Engine Ice Crystal Icing.” Retrieved from: https://pmc.ncbi.nlm.nih.gov/articles/PMC7526622/
- GE Aerospace. (2024). “Test Services – Icing.” Retrieved from: https://www.geaerospace.com/commercial/services/test-services
- Federal Aviation Administration (FAA). (2024). “14 CFR Part 33 – Airworthiness Standards: Aircraft Engines.” Retrieved from: https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-33
- Simple Flying. (2020, July 30). “How Aircraft Engines Are Tested Before Production.” Retrieved from: https://simpleflying.com/how-aircraft-engines-are-tested-before-production/
- TU Graz – Aeroengine Safety. (2024). “5.1.1 Rain [Aeroengine Safety].” Retrieved from: https://aeroenginesafety.tugraz.at/
- NASA Technical Reports. (2015). “Ice Crystal Icing Engine Test Model Development and Sensitivity Analysis.” NTRS 20150022398.
