An aircraft emergency occurs when an airplane faces a situation that threatens the safety of its passengers and crew. This can include mechanical failures, severe weather conditions, or medical emergencies on board. Pilots are trained to handle these situations and follow specific protocols to ensure the safety of everyone on the flight. In response to an aircraft emergency, flight crews may communicate with air traffic control to request priority landing or assistance. Passengers are often instructed on safety procedures, such as using oxygen masks or preparing for an emergency landing. The goal is to manage the situation effectively and minimize risks.