A Ryanair flight bound for Munich returned safely to Thessaloniki on Friday after suffering a serious engine failure shortly after departure, Greek authorities said.During the incident, a fragment from the engine struck and shattered a passenger window, injuring the person seated nearby. Oxygen masks were deployed as a precaution, causing panic among passengers.Authorities said there was no crack or breach in the aircraft’s fuselage, despite initial concerns about the damage.The crew detected the problem while the aircraft was flying over North Macedonia and decided to return to Thessaloniki, as the engine malfunction could not be resolved in flight.After the pilots declared an emergency, standard emergency procedures were activated at Thessaloniki’s Macedonia Airport. Firefighters, ambulances, police and other emergency services were placed on standby. The aircraft landed safely and was later moved to a designated area of the airport.Four passengers were taken to hospital as a precaution for medical checks. Most were examined and discharged, while one remained under observation for further tests.Ryanair arranged a replacement aircraft to fly the majority of passengers to Munich and complete their journey.In a statement to Euronews, Ryainair said the following:”A Ryanair flight from Thessaloniki to Memmingen on Friday morning (10 July) returned to Thessaloniki shortly after take-off when a passenger window dislodged inflight. The aircraft landed normally and passengers returned to the terminal. One passenger requested and received medical assistance on the ground in Thessaloniki. In order to minimise any delay, a replacement aircraft was arranged to bring passengers to Memmingen which departed Thessaloniki at 9:53 local this morning.”The relevant aviation authorities have now launched an investigation into the cause of the engine failure.