A British Airways flight approaching London’s Heathrow Airport declared a “mayday” emergency earlier this month after experiencing technical issues during its descent, aviation authorities have confirmed.

The incident involved an Airbus A320 travelling from Düsseldorf, Germany, to Heathrow on July 6. Despite the emergency declaration, the aircraft landed safely without further complications.

According to France’s Air Safety Investigation Authority (BEA), the emergency was triggered after the aircraft experienced two stall warnings while approaching the airport.

The BEA said the first warning followed a failure in one of the aircraft’s data systems. In response, the flight crew switched the aircraft to an alternative operating mode known as “alternate law,” which reduces some of the aircraft’s automated flight protection functions.

A second stall warning was later activated when the aircraft was flying at an altitude of about 3,000 feet, prompting the crew to upgrade an earlier urgency call to a mayday, the internationally recognised distress signal indicating a serious emergency requiring immediate assistance.

The United Kingdom’s Air Accidents Investigation Branch (AAIB) confirmed that it has opened an investigation into what it described as a serious aviation incident.

“The AAIB is investigating a serious incident involving a commercial aircraft which occurred on 6 July on approach to Heathrow Airport,” the agency said in a statement.

The AAIB added that the case would be handled as a correspondence investigation, meaning investigators would rely on operational records and submitted evidence rather than carrying out on-site field investigations.

British Airways also acknowledged the incident, stating that it is cooperating fully with the AAIB but is unable to comment further while the investigation is ongoing.

Commenting on the incident, aviation safety investigator David Gleave said emergency calls are not uncommon in aviation and can be issued for various reasons, including medical emergencies involving passengers.

However, he noted that declaring a mayday because of a significant technical problem affecting the aircraft itself is far less common, with the decision resting on the captain’s assessment of the situation.