A passenger suffered a severe thumb burn after a portable power bank overheated and emitted heavy smoke aboard HK Express flight UO676 traveling from Hong Kong to South Korea on October 25, 2026. The incident forced the flight crew to initiate emergency fire protocols just minutes before landing at Jeju International Airport. Understanding exactly why this happened and knowing the strict lithium-ion battery rules will prevent you from accidentally triggering a similar mid-air emergency.
What Caused the Smoke on HK Express Flight UO676?
A lithium-ion power bank stored inside a bag underneath a passenger’s seat overheated and caught fire during the descent into Jeju. A Chinese woman in her fifties attempted to manually pull the smoking device out of her bag, which resulted in a painful burn to her left thumb.
The Federal Aviation Administration (FAA) warns that portable batteries can easily enter a dangerous state called thermal runaway. This chemical reaction causes the battery cell to rapidly heat up, swell, and release toxic smoke without any prior warning. Passengers who try to touch or pick up a smoking device frequently suffer severe contact burns from the melting plastic casing.

How the Cabin Crew Handled the In-Flight Battery Emergency
The HK Express flight attendants immediately deployed specialized firefighting equipment to stop the battery from fully igniting inside the packed Airbus A321neo. The crew used heavy safety gloves to grab the smoking device, placed it inside a heat-resistant fire containment bag, and completely submerged it in water.
This specific water-submersion tactic successfully stopped the chemical reaction and prevented the smoke from spreading through the cabin, which was carrying 236 passengers and seven crew members. The aircraft landed normally at Jeju International Airport, where local firefighters boarded the plane to administer first aid. The injured passenger ultimately declined an ambulance ride and traveled to a local hospital independently.
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HK Express Power Bank Rules for Carry-On Baggage
HK Express enforces strict limitations on how many batteries you can bring and exactly where you must store them during the flight. The budget airline, a subsidiary of Cathay Pacific Airways, explicitly forbids passengers from plugging a power bank into their mobile phone or tablet while the aircraft is in the air.
If you plan to fly with this airline, you must memorize these specific battery limitations to avoid confiscation at the security checkpoint.
| Power Bank Policy | HK Express Airline Rule | Safety Reason |
| Maximum Quantity | 2 power banks per passenger | Limits total combustible material in the cabin. |
| In-Flight Charging | Strictly prohibited | Active charging creates excess heat that stresses the battery cells. |
| Storage Location | Under the seat or seatback pocket | Ensures fast crew access if smoke suddenly appears. |
| Overhead Bins | Strictly prohibited | Hidden fires can spread rapidly before anyone detects the smoke. |
Why Airlines Ban Power Banks in Overhead Compartments
Airlines prohibit passengers from placing power banks inside luggage stored in overhead bins because a hidden fire can spread rapidly before anyone notices the smoke. When a battery sits directly under the seat in front of you, you will immediately smell the burning plastic or see the smoke the second a malfunction occurs.
If a battery ignites inside a tightly packed overhead bin, the fire can easily ignite surrounding clothing, plastics, and the aircraft ceiling structure. By keeping the device within arm’s reach, flight attendants can isolate the threat and drop it into a containment bag before a dangerous open flame develops.
Steps to Safely Travel With Lithium-Ion Batteries
Protecting yourself from an in-flight battery fire requires you to inspect your electronics before you even pack your suitcase. The Civil Aviation Department (CAD) in Hong Kong mandates that all spare batteries must travel exclusively in the passenger cabin, never in the unpressurized cargo hold.
Follow these exact safety fixes to ensure your power bank does not trigger a flight diversion:
- Inspect for physical damage: Look closely at the plastic casing of your power bank. If the casing is bulging, cracked, or discolored, throw it away immediately and do not bring it to the airport.
- Tape the terminal ports: Place a small piece of electrical tape over the USB ports to prevent loose metal keys or coins in your bag from causing a short circuit.
- Turn the device off: Ensure the power button is switched completely to the off position before placing it inside your personal backpack.
- Never touch a smoking device: If your device becomes incredibly hot or starts emitting smoke, do not touch it. Press the flight attendant call button immediately and move far away from the seat.
