[Sportschosun, Jang Jong-ho] As an aircraft flies, pilots, air traffic controllers and cabin crew exchange various numbers and words. They may sound meaningless to ordinary people, but when a problem occurs during a flight, they serve as important signals that inform cabin crew and aviation authorities of the situation.
A representative example is the so-called 'squawk code,' which is entered into an aircraft's transponder, a device that automatically transmits and receives signals. When an aircraft enters a four-digit number into its transponder, air traffic controllers can identify the aircraft and determine its flight information.
According to the Daily Mail, one of the most alarming numerical codes is '7500.' It is used when an aircraft faces an aviation security threat, such as hijacking or unlawful seizure of control. The Federal Aviation Administration (FAA) also defines 7500 as the code indicating that an aircraft has been hijacked or is being forced to divert from its destination.
When a controller sees 7500 on the radar screen, special response procedures begin because the situation is not a routine flight operation. However, since the pilot may have entered the number by mistake, air traffic authorities first confirm whether the code was selected intentionally.
'7600' is used when radio communication between an aircraft and ground-based air traffic control is lost. It alerts the ground that the pilot is unable to communicate normally with controllers.
'7700' indicates a broader range of emergencies. It is an emergency code used when an aircraft encounters an urgent problem and requires assistance from air traffic authorities. The FAA instructs pilots to set 7700 when they are facing an emergency and want to notify ground radar facilities. In air traffic control systems, the code appears as an emergency signal.
As a result, there are sometimes reports of aircraft that had set 7700 diverting or landing at an unscheduled airport. The cause can vary, including an engine or aircraft malfunction or a medical emergency involving a passenger or crew member.
Pilots also use expressions that they call out directly to air traffic controllers, not just numerical codes.
The best-known example is 'Mayday.' Mayday is an international distress signal indicating that an aircraft or vessel is facing serious and imminent danger and requires immediate assistance. The International Civil Aviation Organization (ICAO) prescribes the use of 'MAYDAY' when initiating distress communications, and it is generally repeated three times.
For example, if an engine suffers a serious failure or the aircraft's safe flight and landing are threatened, a pilot may tell a controller, "Mayday, Mayday, Mayday."
'Pan-pan' is another important urgency signal used in aviation. Unlike Mayday, it is not reserved for a distress situation requiring immediate rescue. Instead, it is used when an urgent message must be conveyed about the safety of an aircraft or its occupants.
The ICAO distinguishes 'MAYDAY' as a distress signal and 'PAN-PAN' as an urgency signal.
Expressions such as 'Code 300' or 'Angel,' which are used among cabin crew, are somewhat different.
According to Travel + Leisure, which cited aviation industry experts, some airlines or operators may use 'Code 300' or 'Angel' as internal terms for a medical emergency on board. Cabin crew use them to quickly share information when a passenger loses consciousness, becomes seriously ill or otherwise requires medical assistance.
However, unlike 7500 or 7700, these expressions are not standardized official codes across the international aviation industry.
The main reason for using such internal expressions is to share information quickly among crew members without causing unnecessary alarm among passengers.
If an announcement directly told passengers, "A serious medical emergency has occurred involving a passenger," others might become anxious or crowd into the aisle. By contrast, using an established expression among crew members allows them to communicate the situation concisely and take the necessary action. The short numbers and words exchanged by pilots and cabin crew high above the ground thus conceal another safety system that passengers may not know about.
Jang Jong-ho, Reporter bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
