The first warning may not have looked like fire. Perhaps it was an acrid smell, a thread of smoke or sudden heat inside an overhead locker. On IndiGo flight 6E 6115 from Delhi to Chennai on October 11, the cabin crew moved from routine service to fire response, while the pilots changed the flight plan and turned toward Hyderabad.
IndiGo’s confirmed account is narrower, smoke was detected from a passenger’s personal electronic device, the crew brought the situation under control and the aircraft diverted safely to Rajiv Gandhi International Airport. News reports identified the device as a power bank and placed it in an overhead bin but the airline’s public statement did not formally identify the device or establish why it failed.
That distinction matters. A smoking device can be contained in minutes, determining whether it failed through damage, ageing, poor manufacture, an internal short circuit, overcharging or misuse requires examination. There is no publicly released technical finding yet tying this incident to fast charging, counterfeiting or any particular seller.
The fire that can return. Lithium-ion cells store considerable energy in a small package. If damage, overheating, overcharge or an internal fault causes heat generation to outpace heat dissipation, a cell can enter thermal runaway, a self-accelerating reaction producing intense heat, flammable gases, smoke and possible fire.
Putting out the visible flame does not necessarily end the event. US Federal Aviation Administration guidance says a Halon extinguisher can suppress flames but cannot by itself stop thermal runaway; substantial water or another non-alcoholic liquid is used to cool the cells and reduce the risk of propagation or re-ignition. It also advises against moving a hot or smoking device until it has been thoroughly cooled.
In the cabin, the response chain is therefore rapid and disciplined. It works in sequence like alert the pilots, move passengers if necessary, locate the source, protect the crew from smoke, suppress visible flames, cool the battery continuously, isolate it only when safe, and monitor it for the rest of the flight. Passengers should not open a smoking bin, pick up the device or attempt their own improvised response. They should call the crew immediately.
That helps explain why Hyderabad remained necessary even after the crew had contained the immediate danger. Thermal runaway can restart, smoke can conceal damage, and an affected overhead compartment or adjacent baggage may require inspection. A diversion is not triggered by a single universal threshold. The pilot in command weighs the device’s condition, continuing heat or fumes, success of the cabin response, aircraft systems, remaining flight time and the suitability of nearby airports. In this case, an airport official said no emergency or priority landing was needed because the fire had already been extinguished, but IndiGo still diverted under its established protocols and arranged an alternate aircraft for the onward journey.
Why batteries stay visible. Power banks are treated as spare batteries because their principal purpose is to supply electricity to another device. International guidance, therefore, requires them to remain in cabin baggage rather than checked luggage with terminals protected against short circuits, batteries up to 100 watt-hours are generally allowed, those from 100 to 160 Wh require airline approval under the broader international framework and larger batteries are normally prohibited on passenger aircraft.
The logic is not that the cabin cannot burn. It is that heat, swelling, odour or smoke can be detected and reached there, while a battery fire inside the hold may develop behind baggage and structural liners before anyone can intervene.
India has gone further on accessibility. Following a November 2025 DGCA advisory, Indian airlines tell passengers not to use or recharge power banks in flight and not to place them in overhead bins. IndiGo’s published policy requires power banks to stay within personal reach, under the seat, in the seat pocket or on the passenger, and generally limits travellers to two power banks of no more than 100 Wh.
The reported location of the device on 6E 6115, therefore, raises an enforcement question as important as the battery’s origin, if it was in an overhead compartment, how did it get there despite a rule designed specifically to preserve visibility and access? Security screening can identify prohibited items, but preventing a permitted power bank from being moved into an overhead bin also depends on clear warnings, gate practice, cabin announcements and passenger compliance.
DGCA has directed operators to review lithium-battery risks, strengthen early detection and firefighting procedures, train crews to recognise overheating, smoke and flames, and ensure that protective equipment, extinguishers and fire-containment kits are accessible and serviceable.
Power banks are not the only concern. Phones, laptops, tablets, cameras, vapes and spare batteries can all fail. US aviation data should not be assumed to describe India exactly, but it shows how the risk profile can change. UL Standards & Engagement reported that e-cigarettes led reported passenger-flight incidents in 2023, while portable chargers became the leading category in 2025, accounting for 30 percent.
The common risk factors are more useful than a device ranking, swollen or punctured cells, crushed casings, exposed terminals, overheating, water damage, ageing, incompatible chargers and questionable battery-management electronics. Warning signs include unusual warmth, bulging, hissing, popping, chemical odour, smoke or venting gas.
How to handle power bank, here are some useful instructions from Tailwind Times:
• Carry power banks only in hand baggage and remove them if the bag is gate-checked. • Keep them within reach, not in an overhead bin, on Indian flights applying the DGCA advisory. • Do not use or charge a power bank aboard the aircraft. • Protect terminals and carry each spare battery in original packaging or a separate protective pouch. • Do not fly with a swollen, damaged, unusually hot or unlabelled battery. • Check the watt-hour marking up to 100 Wh is the ordinary limit, subject to the airline’s own rules. • Tell the cabin crew immediately about heat, swelling, odour, hissing or smoke, do not wait for a flame.
India requires portable lithium cells and batteries to meet the safety standard IS 16046 under the Bureau of Indian Standards’ compulsory registration framework. That creates a regulatory filter, but it cannot protect a passenger who buys an untraceable imitation, continues using a swollen unit or carries a product whose label does not reliably state its watt-hour capacity.
The success of flight 6E 6115 was not that nothing happened. Something did happen, and the safety chain held, the crew detected and contained the event, the pilots chose a suitable airport, and the aircraft landed without reported injury.
One power bank changed one flight plan. The lesson is that lithium-battery safety begins long before smoke appears at manufacture, online sale, packing, security screening and the moment a passenger decides where to put the device.