(JEJU, SOUTH KOREA) — Passengers boarding Jin Air Flight LJ436 got an abrupt reminder to stay alert at the gate: smoke entered the cabin, prompting an evacuation of all 122 people on board at Jeju International Airport on Friday.
The incident happened around 12:25 p.m. local time as the Jeju-to-Pohang-Gyeongju flight prepared for departure. Smoke entered the aircraft during boarding, and an alarm was triggered in the cockpit and control room.
Everyone evacuated safely, and there were no reported injuries. Officials also said there was no fire, and the airport’s air fire brigade was not dispatched.
Jin Air later said its inspection found the smoke came from overheating in the aircraft’s auxiliary power unit (APU). The APU is the small tail-mounted engine that supplies power and air conditioning when the main engines are off. The airline said the overheating was caused by an internal malfunction.
After checks, Jin Air rescheduled the flight for 4:35 p.m. the same day.
Immediate traveler impact
For travelers, the immediate takeaway is practical: if you were on LJ436 or connecting onward, you likely faced a multi-hour delay. On a short domestic hop like Jeju (CJU) to Pohang-Gyeongju (KPOH), that can still disrupt afternoon plans.
Delays of this length can trigger:
- Missed hotel check-in windows
- Missed tour departures
- Missed onward rail or bus connections
What we know so far
Smoke events during boarding can be unnerving, even when they do not turn into a fire. Evacuations are ordered conservatively because smoke in a closed cabin can become dangerous quickly.
The fact that there were no injuries is important. Evacuations themselves can cause injuries (for example, during slide use), even without flames.
Jin Air’s initial assessment points to the APU. That matters because the APU is used heavily on the ground and often runs during turnarounds to keep the cabin comfortable. When something goes wrong, you can see smoke or smell fumes before pushback.
Flight details at a glance
| Detail | Information |
|---|---|
| Flight | Jin Air Flight LJ436 |
| Route | Jeju (CJU) → Pohang-Gyeongju (KPOH) |
| Airport | Jeju International Airport |
| When | Jan. 2, 2026, about 12:25 p.m. local time |
| People onboard | 122 passengers and crew |
| Reported cause | Overheating in the auxiliary power unit (APU) |
| Outcome | Evacuation, no injuries reported |
| Rescheduled departure | 4:35 p.m. local time |
What to do if your flight is evacuated or delayed like this
Even when an airline gets you moving again the same day, paperwork matters. You will be in a better position for refunds, insurance claims, or employer reimbursement if you document everything.
Action checklist:
- Save your boarding pass and any delay notices (screenshots count).
- Keep receipts for out-of-pocket costs you would not have paid otherwise (meals, transport, accommodation).
- Notify separately booked connections (rail, bus, another airline) immediately if you might miss them.
Pro tip: If you used a travel credit card, check its trip delay coverage rules right away. Many policies require a minimum delay and itemized receipts.
Miles and points: how this can affect your earning
Jin Air is a low-cost carrier (LCC), and most travelers on such carriers are earning through credit card spend rather than traditional airline miles.
How disruptions can change the math:
- If Jin Air reaccommodates you on a different flight number or day, your credit card travel protections may be more important than miles.
- If you rebook on a competitor at your own expense to protect plans, consider using flexible bank points to erase or rebook purchases.
- If you’re status-chasing with a full-service program, a last-minute switch to another airline may help—this depends on the ticket and how that carrier awards credit.
For those earning elite credit on Korean domestic flying, full-service carriers typically offer clearer status pathways than most LCCs. That can matter for lounge access, fee waivers, or upgrades later.
How this stacks up against other Korea LCC options
Jeju is one of the busiest domestic and leisure markets in the world, with many low-cost choices including Jeju Air, T’way Air, Air Busan, and Eastar Jet. Competitive pressure keeps fares low but also means tight schedules.
When an aircraft goes out of service unexpectedly, LCC fleets can have less spare capacity for quick swaps. This is common across the low-cost sector:
- Same-day recovery often depends on finding another aircraft and crew.
- When that’s not possible, the practical alternatives are rebooking on a later flight or refunding and letting you self-connect.
What travelers at Jeju should watch today
If you’re flying out of Jeju International Airport this afternoon, build extra buffer time into your plans. Aircraft swaps and gate changes can happen quickly after a maintenance event.
Practical steps to take now:
- Monitor departure screens and airline app notifications closely.
- If your flight is on Jin Air Flight LJ436, confirm whether you’re on the 4:35 p.m. departure or have been moved.
- If you cannot afford another delay, price out same-day seats on competing carriers before inventory tightens closer to departure.
Warning: After a maintenance event, gate assignments and aircraft types may change without much notice. Keep phones on and notifications enabled.
Jin Air Flight LJ436 experienced a smoke event at Jeju International Airport during boarding, leading to a safe evacuation of 122 people. The smoke was caused by an overheating auxiliary power unit (APU). No injuries occurred, and the flight was rescheduled for later that day. Passengers are encouraged to document expenses for travel insurance claims and check status for connecting domestic travel.
