Delta Air Lines
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LISBON — A Delta Air Lines flight from Barcelona to Boston made an emergency landing in Porto, Portugal, on Sunday after smoke was reported in the cabin, and at least 11 passengers received medical treatment, according to Reuters and Portuguese authorities. No serious injuries have been reported.

Flight DL251 was diverted to Porto following a reported mechanical issue and landed safely, Delta said. Data from the tracking service Flightradar24 suggested the aircraft left Barcelona at 3:15 p.m. local time (1315 GMT) and touched down at Porto's Francisco Sá Carneiro Airport at 5:45 p.m. local time (1645 GMT).

A spokesperson for Portugal's emergency and civil protection authority told Reuters by phone that eight passengers were treated on the tarmac and three others were taken to hospital for treatment. The spokesperson said the forced landing was due to smoke in the cabin. The aircraft was an Airbus A330.

Reports differed slightly on how many people needed care. AFP, citing Portugal's civil protection service, reported that 14 passengers needed medical help after the landing, according to a summary of its report by the outlet Andhravilas. Another outlet that cited AFP said several passengers were treated for smoke inhalation and a few were taken to hospital with what officials described as light symptoms. The aviation news site AirLive reported that four people were taken to hospital, while Reuters' figure was three. The differences may reflect how each outlet counted people who received treatment at the airport and those who went to hospital, and Delta has not published its own tally.

Media reports cited by AFP said the aircraft was carrying 296 passengers. The remaining passengers left the plane safely, according to accounts carried by several outlets. Portuguese emergency teams responded in force, with about 60 personnel deployed to the scene, according to the aviation news site Meyka, which also reported that additional resources were mobilized and later stood down as the situation stabilized. The Andhravilas summary said an alert level 2 was activated. Air traffic at the airport was briefly suspended during the landing and then resumed, Meyka reported.

According to The Aviation Hub, a site that tracks flight emergencies, the jet turned back to the southeast just before its Atlantic crossing after heading west from Barcelona. The crew declared an emergency by squawking 7700, the universal transponder code for a general emergency, and diverted to Porto in northern Portugal, where it landed without further incident, the site reported. AirLive said air traffic controllers directed the wide-body jet toward Porto and that it landed on the airport's Runway 35. Accounts vary on exactly where the plane was when the crew turned back, with some outlets describing it as over the Atlantic and others saying it had not yet begun the ocean crossing.

The cause of the smoke has not been announced. Delta described the diversion only as the result of a reported mechanical issue, and the Portuguese authority said the landing was due to smoke in the cabin. Meyka reported that Delta had not disclosed the source of the smoke or the identities of those hospitalized. It was not immediately clear from the coverage reviewed whether Portuguese or U.S. aviation authorities had opened an investigation. An aviation commentary published by the outlet Rolling Out noted that Delta and aviation authorities will need to identify the source of the smoke before the plane flies again.

The same commentary said smoke in a sealed cabin is one of the situations flight crews train for most intensively, and suggested that turning back before the Atlantic crossing may have been significant. That is an observation from the outlet rather than a finding by investigators, and the available reporting does not establish what the crew's decision-making was or how the situation developed in the cabin.

The disruption spread beyond the flight itself. AirLive and Meyka reported that Delta rescheduled the continuation of the trip to Boston for Monday, September 28, at 1 p.m. local time, and that connected flights DL276 and DL277 were canceled because the aircraft and crew were out of position. Passengers were being rebooked on alternative routes or provided accommodations while they waited, AirLive said. The Resident, cited by Andhravilas, reported that the remaining passengers were waiting for an alternative flight scheduled for the next afternoon. Delta has not confirmed those arrangements in the coverage reviewed, so passengers should check with the airline for the latest information.

Delta said the flight landed safely, and the Portuguese authority's account of the medical response is the main confirmed detail beyond that. None of the sources reviewed included direct quotes from Delta, the Portuguese authority or passengers, so this report relies on their published statements as relayed by Reuters and other outlets.

For now, the confirmed picture is that a Delta A330 carrying hundreds of passengers diverted to Porto with smoke in the cabin, landed safely, and that a small number of passengers needed medical attention. Further details are expected to emerge as Delta, Portuguese officials and aviation authorities release more information about what caused the smoke and how the incident unfolded.