A Boston-bound Delta A330 diverted to Portugal after smoke was reported in the cabin

Delta Air Lines flight DL251, an Airbus A330 flying from Barcelona to Boston, diverted to Porto, Portugal, on Sunday, September 27, after smoke was reported in the cabin. The aircraft landed at Francisco Sá Carneiro Airport without a fire being reported, and passengers were checked by emergency crews on the ground. No cause has been made public.

The airline has said only that the diversion followed a reported mechanical issue. Portuguese civil protection officials and Reuters gave different counts of how many passengers needed care, so each number below is attributed to the source that gave it. Nothing published so far describes a fire, and the reports agree that the aircraft landed safely.

What is confirmed about the flight

According to FOX 5 New York, the jet left Barcelona at 3:15 p.m. on the Sunday and touched down in Porto about two and a half hours later. Some reports are dated September 28 because they were published the next day, but the Portuguese coverage places the emergency on September 27.

A source in the sub-regional command of Portugal’s National Authority for Emergency and Civil Protection told the press that “foi dado um alerta no Aeroporto Sá Carneiro às 17h33 por fumo na cabine de um avião A330,” meaning an alert was raised at 17:33 for smoke in the cabin of an A330. The same source said the aircraft “aterrou em segurança,” or landed safely, and the emergency status was lifted at 19:30, according to Jornal Económico.

Landing times differ slightly by outlet. Observador put the touchdown at 17:59 local time, while other reports gave roughly 17:45 in Porto, and the 17:33 alert suggests the crew had already reported the smoke to controllers before the aircraft reached the runway. The Barcelona-to-Boston route normally crosses the Atlantic, so the jet was roughly two hours into its journey when it turned toward Portugal, MiGFlug said.

The aircraft was an A330-300 carrying 296 passengers, per the aviation site MiGFlug, which listed the registration as N824NW. That site also reported that the crew declared an emergency with the 7700 transponder code before diverting.

Two sets of casualty numbers

Reuters-based reports, including FOX 5, say first responders treated eight passengers on the tarmac and took three more to a local hospital. The Portuguese count is higher. Observador reported that 14 people received medical assistance and four were taken to Hospital de São João for smoke inhalation, all with minor injuries, and that civil protection issued a level 2 alert on a three-level scale.

The jornaleconomico report quotes the same civil protection source on 14 people assisted and four hospitalized with “inalação de fumos,” and says roughly 60 emergency personnel and 22 vehicles were on site. Observador counted 27 personnel and 14 ground units, so resource figures also vary by outlet. No source read for this article gives a single reconciled tally, and none reports a serious injury.

What Delta and the airport have said

Delta told Reuters the flight diverted “following a reported mechanical issue and landed safely,” MiGFlug reported. The airline did not describe the source of the smoke, and no statement from Delta or from Portuguese authorities has said whether the cabin filled with smoke or whether it was limited to one area of the aircraft. ANA Airports of Portugal, which operates the airport, said the flight diverted for technical reasons and that passengers left the aircraft with medical assistance available on site, according to Observador.

According to Rus Tourism News, the airport’s operations were briefly affected during the response and no fire was reported. That outlet also noted that crews treat any unexplained smoke or burning smell as potentially serious until the source is found, which is why a diversion is the standard response even when a fire is not confirmed.

Aircraft status and open questions

Flight-tracking data cited by FOX 5 showed that the aircraft’s scheduled flights on Monday, September 28, were canceled. MiGFlug reported that Delta planned to carry passengers on to Boston the following day and that two connecting flights were canceled. Observador likewise said the rescheduled Boston service was expected on September 28. ANA Airports of Portugal indicated the rescheduled Boston flight would operate the day after the diversion, which means passengers were expected to reach their destination roughly a day late, though the sources do not say where they spent the night.

MiGFlug lists galley equipment, electrical faults, air-conditioning packs and lithium batteries as common sources of cabin smoke in general, but it states that the actual cause here remained undetermined as of September 28. Delta had not identified a cause, and no investigation announcement from Portuguese aviation authorities was found in the sources reviewed. The open questions are what produced the smoke aboard N824NW and whether the airline or Portugal’s accident investigators will publish findings.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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