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When Air India Flight AI171 plunged moments after takeoff from Ahmedabad on June 12, killing nearly all on board and dozens on the ground, it marked not just a national tragedy, but a catastrophic failure in understanding — or respecting — physical reality. As a physicist, I cannot explain this event through emotion or outrage alone. I must explain it through motion, energy, and systems that either align with natural laws or fail catastrophically when they don’t.

The Boeing 787 Dreamliner is not just a flying machine; it is a physical equation in motion. It operates in a space where Newton’s laws, Bernoulli’s principle, and thermodynamic limits converge — all while relying on electronics, software, and human judgment to keep it within safe margins. When a plane crashes 30 seconds after liftoff, as Flight AI171 did, physics hasn’t malfunctioned. It has operated precisely. What failed was everything else.

Let’s start with lift. An aircraft rises because air pressure over the curved top of the wing is lower than the pressure below, generating upward force — a result of Bernoulli’s principle. But this only works within a narrow band of speed, angle, and air density. Failure to achieve sufficient speed or a misconfigured wing flap can steeply reduce lift. Combine this with inadequate thrust — Newton’s Second Law in its most unforgiving form — and you have the perfect setup for loss of altitude.
The preliminary reports and flight data — if consistent with early visual evidence — suggest that AI171 never entered stable climb. This is critical: the first 60 seconds of flight are the most sensitive, especially in a wide-body aircraft like the Dreamliner, which carries a takeoff weight of around 230,000 kilograms. That weight requires not only thrust but precision — every second matters, every sensor reading is vital.

Physics does not permit negotiation. If thrust is lower than expected — due to engine error, misreading of fuel-air mixture, or even a software miscue — the result is insufficient acceleration. If flaps are retracted too early or deployed incorrectly, they can induce a stall. If the angle of attack becomes too steep too soon, airflow detaches from the wings, and lift vanishes. All of this, I should stress, can happen in the span of five to ten seconds. The consequences are irreversible.

Here’s a more brutal truth: by the time the aircraft descended back toward the city, carrying over 125,000 litres of jet fuel, the kinetic energy of its fall exceeded 1.2 billion joules — enough to obliterate buildings and ignite a firestorm. The 33 civilian deaths on the ground were not incidental. They were inevitable, given the energy and mass of the falling aircraft. Conservation of momentum is not just a principle in a textbook; it is why the impact zone became a crater.

Some have called this a “technical failure.” I disagree. A technical failure becomes a fatal failure only when it is unmanaged. And in this case, management must include system redundancy, real-time alerts, pilot override authority, and infrastructural preparedness to prevent population centres from becoming crash zones. The crash site — near a medical college and densely populated — underscores a deeper policy failure: we continue to expand air routes and civil aviation without considering urban flight safety corridors. That’s not just poor planning. It’s a fundamental disregard for physics in urban design.

The lone survivor — seated near an emergency exit — is not a statistical miracle. His survival likely correlates with position, structural shielding, and time-to-evacuation. The aircraft’s fuselage ruptured along predictable shear lines. In physics, we know that energy does not distribute equally — it concentrates along weakest zones. Those in mid-cabin took the brunt of impact force; those near structural escape lines had a narrow window for survival. This is tragic, but it is not random. It is mechanics.Where does this leave us?

India aspires to be a global aviation hub, aircraft builder, drone manufacturer, and spacefaring power. But physics does not respect ambition; it respects accuracy, redundancy, and limits. The Directorate General of Civil Aviation (DGCA) is now investigating. But as a physicist, I urge them to go beyond checklists and into systems physics: Is data from engines and wing sensors being monitored in real time? Are pilot override thresholds based on energy gradients, or outdated software heuristics? 

Are maintenance checks being carried out with entropy in mind — that is, understanding that all systems degrade, and some degrade faster under Indian operating conditions?

The Dreamliner is a triumph of engineering. But no engineering is immune to entropy — the second law of thermodynamics applies to all aircraft fleets. Unless we design systems that expect failure, detect it early, and allow humans or machines to respond within seconds, we are building catastrophes in slow motion.
This crash should be the final warning. Let us not simplify this as “one bad day.” It was a complex failure, yes — but one that physics could have predicted, if systems were calibrated to listen. Black boxes may eventually tell us what failed. But as a scientist, I already know what didn’t: the laws of motion, energy, and force. Those laws worked. The rest did not.

And until we align our institutions, infrastructure, and decision-making to those laws — not just in aviation, but in every system that governs human life — we will continue to mistake the predictable for the unexpected.

Nishant Sahdev is a theoretical physicist at the University of North Carolina at Chapel Hill, United States. He posts on X @NishantSahdev. Views are personal