Delta DL251 to Boston Turned Back Over the Atlantic With Smoke in the Cabin, and Four Passengers Went to Hospital in Porto

Delta Air Lines flight DL251 from Barcelona to Boston made an emergency landing in Porto, Portugal, on Sunday, September 27, 2026, after smoke was reported in the cabin. Portugal’s civil protection authority said 14 people were treated after the landing and four passengers were taken to hospital with minor injuries from smoke inhalation.

The jet was an Airbus A330-300 carrying 296 passengers, according to the civil protection authority. At the time of writing, neither Delta nor the Portuguese authorities had said what caused the smoke.

What happened on DL251

The A330 left Barcelona-El Prat at about 3:15 p.m. local time, based on Flightradar24 data cited by Reuters. Flight tracking reported by AIRLIVE shows it cruising west at 32,000 feet over the Atlantic when the crew declared an emergency, roughly two hours into the flight, and turned back toward Portugal.

AIRLIVE and the Portuguese aviation site NewsAvia both identify the aircraft as N824NW. The FAA registry lists that jet as an A330-302 built in 2015, registered to Delta and fitted with GE CF6-80E1 engines.

According to NewsAvia, the crew told Porto’s tower that some passengers felt unwell and were being given oxygen. The newspaper SOL reported that some passengers used oxygen masks during the flight.

The civil protection authority’s Porto command said the alert was raised at 5:33 p.m. Portugal’s airport operator, ANA, said the jet landed safely at Francisco Sá Carneiro Airport at 5:57 p.m., and that passengers got off and received medical care on the spot.

A level 2 alert, on a scale of one to three, brought 67 firefighters and 22 vehicles to the airport, Jornal de Notícias reported, as relayed by Renascença. Airport movements stopped for a few minutes, leaving several aircraft waiting to land.

Two different injury counts

The published figures do not all match. A civil protection spokesperson told Reuters that eight passengers were treated on the apron and three were taken to hospital.

The authority’s Porto command gave the Lusa news agency a higher count: 14 people assisted and four taken to Hospital de São João for smoke inhalation, all classed as minor injuries. The authority gave the same figures to AFP and to Renascença. NewsAvia, citing Lusa, reported that none of the four was admitted, and the alert was stood down at about 7:30 p.m.

Delta told Reuters that the flight diverted after a reported mechanical issue and landed safely. ANA described the diversion as being for technical reasons and said the flight to Boston was expected to operate the next day. NewsAvia reported that passengers and crew were taken to a hotel in Porto overnight.

Why smoke turns a transatlantic jet around

FAA guidance tells crews to start planning an emergency landing at the first sign of fire, not once they know how bad it is. Its advisory circular on in-flight fires says tests have shown a fire that spreads into an aircraft’s overhead area can become uncontrollable in as few as 8 to 10 minutes.

The same guidance says a crew may have as few as 15 to 20 minutes to get the aircraft on the ground if a hidden fire is left to progress. In a fire, it tells pilots to plan for an immediate descent and a landing at the nearest suitable airport.

For a jet heading west over the Atlantic, the nearest suitable airport may be the one behind it. The FAA notes that most cabin events are brought under control without an emergency landing, but it is explicit that a delay of a couple of minutes can decide the outcome if the fire is hidden.

Turning back toward Portugal put DL251 within reach of a major airport, where firefighters and ambulances were waiting when it landed. The cost is a jet, a crew and 296 passengers left in Porto overnight, with the onward flight to Boston rescheduled for the next day.

The second Delta A330 out of Barcelona to turn back in three days

DL251 came two days after another Delta A330 out of Barcelona had to return. On September 25, flight DL195 to Atlanta went back to El Prat after its left engine produced bangs and flames shortly after takeoff.

They were different aircraft: DL195 was flown by N813NW and DL251 by N824NW. They also involved different problems, an engine on one and cabin smoke on the other.

It is not the first A330 smoke diversion over the Atlantic this year. In July, a SWISS A330 diverted to Bangor after smoke filled its business class cabin over the Atlantic.