The Dubai Airshow 2025 is underway, and India’s Light Combat Aircraft (LCA) Tejas has once again attracted significant attention. A recent video circulating on social media shows water dripping from the belly section of the Tejas, prompting speculation about a possible leak. Some online commentators suggested an “oil leak,” raising questions about aircraft performance and reliability.
However, the truth is far simpler and firmly grounded in standard aviation engineering practices.
This article explains what the video actually shows, why water discharge is normal, and how modern aircraft including Tejas manage environmental control systems.
Is LCA Tejas Leaking Oil? No, It’s Condensed Water
The fluid seen in the viral video is not oil, but condensed water. Nearly every aircraft, military or civilian discharges water during and after operation. This is a routine effect of the Environmental Control System (ECS).
In fact, the absence of such condensation in certain conditions can indicate a malfunction.
Water dripping from an aircraft on the ground is, therefore, an indicator of a functioning cooling and pressurization system, not a defect.
This concept is similar to how air conditioners in homes release water as a result of cooling warm, humid air.
Understanding the Engineering: What Is Bleed Air and Why Does Condensation Occur?
Modern jet aircraft use a process called bleed air extraction, in which a small, controlled amount of highly pressurized, high-temperature air is drawn from the engine’s compressor stage. This air is used for multiple critical functions:
- Cabin and cockpit pressurization
- Air-conditioning and temperature regulation
- Anti-icing and de-icing functions
- Pressurizing pneumatic and hydraulic systems
Why the Raw Bleed Air Is Not Used Directly
The extracted bleed air is too hot and at too high a pressure to be used in its original state.
Therefore, the aircraft’s ECS performs the following steps:
- Pressure reduction
- Cooling through heat exchangers
- Moisture removal through a condenser
When bleed air cools, water vapour condenses, just as it does in household AC units. This condensed water is then collected and expelled overboard through dedicated drainage outlets, typically located under the fuselage.
This is exactly what was seen in the Tejas video.
Why Do Almost All Aircraft Drip Water?
This phenomenon is not unique to Tejas.
Aircraft such as the Rafale, Eurofighter Typhoon, F-16, F-18, and even large commercial jets exhibit the same water discharge patterns.
Additionally:
- In colder climates, moisture expelled from the drainage outlet can freeze, sometimes forming thin ice around the duct.
- During regular operations, ground crews expect minor water discharge as part of the ECS cycle.
Thus, water dripping from an aircraft is part of normal ECS operation, not a failure.
How 5th-Generation Fighters Handle Heat Management Differently
While 4th-generation fighters rely on bleed-air-driven ECS, next-generation aircraft use closed-loop thermal management systems.
Closed-loop cooling in AMCA and F-35
The upcoming AMCA (Advanced Medium Combat Aircraft) and the F-35 Lightning II use:
- Closed-loop coolant circulation
- Centrifugal water separators
- Advanced heat exchangers
- Integrated fuel-based thermal management
These systems ensure that no free moisture is released externally. They are more efficient and are designed to support the high thermal loads generated by modern avionics and stealth features.
Why Social Media Misinterpretations Occur
Aircraft systems are highly complex, and without knowledge of aviation engineering, some phenomena can be easily misunderstood. A video of water discharge can appear alarming to the untrained eye, even though it is routine.
The combination of limited technical awareness and rapid content sharing often leads to misinterpretations. This is why many harmless aircraft behaviours like condensation trails, ECS drains, or engine spooling sounds become viral topics online.
LCA Tejas Is Functioning Exactly as Designed
The water seen dripping from the underbelly of the LCA Tejas at the Dubai Airshow 2025 is a standard by-product of its Environmental Control System, not an oil leak or mechanical failure.
Understanding the science behind such occurrences is essential for accurate interpretation of aviation footage and for appreciating the sophistication of modern aircraft systems.
As Tejas continues to represent India at major international airshows, it stands as a testament to the country’s growing aerospace engineering capabilities.