Oxygen System Leak Behind 8 Hour Lufthansa Flight To Nowhere

Last week Lufthansa passengers expecting to fly from Frankfurt to Rio De Janeiro ended up taking an eight and a half hour flight back to Frankfurt. The Boeing 747 opted to return to Frankfurt when a leak in the emergency oxygen system was detected.

Lufthansa, Boeing 747, Oxygen Leak
A Lufthansa Boeing 747 had to return to Frankfurt on the 27th of December. Photo: Oliver Roesler via Lufthansa

Over the months, we’ve seen several long ‘flights to nowhere‘. These occur when the pilot can’t proceed to the destination but also doesn’t need to land immediately. One of these saw a KLM Boeing 747 fly for 11-hours. The reason behind the return to origin was given as a volcano in Mexico, combined with a number of racehorses onboard.


On the 27th of December, LH 500 became one such flight. The flight was operated by a Boeing 747-400 registered as D-ABTL. According to Planespotters, this is an 18-year-old aircraft, delivered to Lufthansa in 2002.

The flight was due to depart from Frankfurt at 21:55, however, it didn’t get airborne until an hour later at 22:55. The aircraft had 373 passengers on board. Following its departure, the aircraft climbed as normal until it reached 35,000 feet. However, while cruising past the Canary Islands around four and a half hours into the trip, the pilots detected a problem with the aircraft.

Lufthansa, Boeing 747, Oxygen Leak
The aircraft turned around while passing the Canary Islands. Image: FlightRadar24.com

Emergency oxygen system leak

The Boeing 747’s emergency oxygen system was leaking. If the cabin pressure is lost at high altitudes, this system provides oxygen while the aircraft descends to a safe altitude where humans can breathe unaided. Lufthansa confirmed to Simple Flying that this system had been functioning on departure from Frankfurt.

As a result, the aircraft descended to 14,000 feet. The airline mentioned that at this altitude, the emergency oxygen system would not be required in the event of depressurisation. Having completed its descent to 14,000 feet, the aircraft proceeded to fly back towards its origin, Frankfurt. According to data from FlightRadar24.com, the aircraft touched back down at the German aviation capital at 07:23 local time.

Following the return to Frankfurt, the aircraft had remained on the ground until today. It took to the skies again at 14:36 today, as LH446 to Denver.

Lufthansa’s response

In response to a request for comment from Simple Flying, a Lufthansa spokesperson said:

“During the flight to Rio de Janeiro (LH500,  Fri 27 Dec 2019, FRA-GIG, B747-400, D-ABTL, 373 passengers) the cockpit crew noticed a leakage in the Emergency Oxygen System for the passengers. This leakage only appeared during the flight, as it was already checked and approved okay before take-off at 22:56 (LT). This system is used only in the rare case when the cabin pressurization system has a failure.”

Lufthansa, Boeing 747, Oxygen Leak
Lufthansa placed the passengers on a replacement aircraft. Photo: Oliver Roesler via Lufthansa

They added: “Although the pressurization of the cabin was normal during the entire flight, the crew decided as a precautionary measure and according to the procedures, to descend to a lower flight level 140 (14,000 feet = 4,267 meters) on which the Emergency Oxygen System would not be needed anymore. On that lower altitude the crew returned the aircraft back to Frankfurt, where it landed safely and normally at 07:34 (LT, 28 Dec). The passengers flew to Rio with a replacement aircraft, departing the same morning. The safety of this flight for passengers and crew was not in danger at any time.”

Were you onboard LH500? What do you make of the incident? Let us know your thoughts in the comments!