LISBON — A transatlantic Delta Air Lines flight suffered a prolonged mid-air detour on Monday evening after a mechanical issue forced the aircraft to abandon its flight path over the North Atlantic, initially targeting Iceland before making a dramatic turn south to land in Portugal.
Delta Air Lines Flight DL155, operated by a Boeing 767-300ER (registration N180DN), departed Dublin Airport on Monday, August 3, at 5:10 PM local time—roughly two hours behind its scheduled departure.
Unexpected Detour Across the Atlantic
After climbing to its cruising altitude of 34,000 feet, the aircraft began its standard route westward across the ocean. However, short of reaching full oceanic crossing, the flight crew identified a technical issue onboard.
Initial flight tracking data showed the aircraft executing a right turn towards Keflavík International Airport (KEF) in Iceland, the standard emergency diversion point for North Atlantic routes. Shortly thereafter, crew and airline operations made the unexpected decision to bypass Iceland entirely and redirect the aircraft hundreds of miles south toward Lisbon, Portugal (LIS).
According to operational updates, technical specifications associated with the aircraft’s specific mechanical failure mandated a diversion to an airport with a warmer ground climate, ruling out the cooler conditions at Keflavík.
Flight Timeline (DL155 - Aug 3, 2026)
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17:10 IST | Departure from Dublin (DUB) [2 hours delayed]
~18:30 IST | Reached 34,000 ft cruising altitude over Atlantic
~19:15 IST | Technical issue reported; initial turn toward Iceland (KEF)
~19:45 IST | Flight plan revised south toward Lisbon, Portugal (LIS)
~23:25 WEST | Safe landing at Lisbon Airport (LIS) after >6 hours in air
The twin-engine widebody landed safely at Lisbon Airport more than six hours after departing Dublin. Passengers were disembarked, and the remainder of the flight was officially canceled for the evening.
Aging Widebody Fleet in the Spotlight
The aircraft involved, registered as N180DN, was delivered to Delta in 1992, making the airframe 34 years old. It stands as one of the oldest active passenger aircraft operating in Delta’s global fleet.
| Aircraft Details | Specification |
| Model | Boeing 767-300ER |
| Registration | N180DN |
| Age | 34 years (Delivered April 1992) |
| Fleet Status | Among Delta’s oldest active widebody jets |
Delta has been actively working to phase out its aging Boeing 767-300ER fleet, which averages around 28 years of age, replacing them with modern, fuel-efficient Airbus A330-900neo and A350-900 aircraft. However, several older 767s remain in active transatlantic service.
Passenger Status and Next Steps
Following the cancellation in Lisbon, stranded passengers were provided hotel accommodations and rebooking assistance. The flight is now expected to resume its journey from Lisbon on Wednesday, August 5, 2026, at 10:45 AM local time, pending maintenance clearance or an aircraft swap.
