24-05-2025
Delhi-Srinagar flight incident: What's the difference between PAN PAN and Mayday aviation emergency signals?
After the recent Indigo Delhi-Srinagar flight encountered a hailstorm mid-air, the Directorate General of Civil Aviation (DGCA) stated that the crew followed all emergency procedures before declaring a 'PAN PAN' to Srinagar Air Traffic Control (ATC), and requested for RADAR vectors. The aircraft landed safely, with no injuries reported, and Auto Thrust functioning normally.
This incident prompted a closer look at the two key aviation distress signals used by pilots to convey urgency or emergency situations: PAN PAN and Mayday. What do they mean, and how are they different? Experts weigh in.
Colonel Rajgopalan, the founder of Aviation Training India, explained that Mayday is used for life-threatening emergencies, while PAN PAN indicates an urgent but 'non-life-threatening' situation. 'Mayday is reserved for the most serious emergencies where life or the safety of the aircraft is in immediate danger,' he said. 'PAN PAN is a step below Mayday and is used when something is urgent, but does not pose a direct risk to life. Both signals help pilots communicate clearly with air traffic control,' he said.
Rajagopalan also said, 'If a pilot cannot communicate with air traffic control, they can make a distress call on the VHF Guard frequency, 121.5 MHz.'
When would a pilot use Mayday?
Dhairyashil Vandekar, an aviation expert and analyst, said Mayday is used in scenarios involving 'grave and imminent danger,' such as severe aircraft malfunction (like engine failure), onboard fires, cardiac arrest, or hijacking. 'Mayday comes from the French m'aidez, which means 'help me',' he said. 'It signals that the aircraft needs immediate assistance and takes priority over all other radio communications.'
What does PAN PAN signal mean?
PAN PAN, on the other hand, is used to convey urgent situations that also require prompt attention but are not as life-threatening.
'Such situations may be created by engine failure, but without any risk of crashing or non-critical medical situations like a minor injury, illness, weather-related issues etc. PAN PAN originates from the French word 'panne' meaning 'breakdown',' said Vandekar.
How is an aviation distress call transmitted?
In emergency inflight situations, Vandekar asserted that the pilot usually transmits a message to ATC beginning with mayday or PAN PAN repeated thrice, followed by a declaration of emergency, the reason for it, and requesting priority handling and assistance. 'ATC is also informed of the aircraft call sign, type of emergency, aircraft location, and intention of the pilot, like wanting to divert or emergency services required etc,' said Vandekar.
Why correct usage matters
Experts stressed the importance of using the correct signal to avoid miscommunication and ensure the right response.
'Confusing PAN PAN with Mayday can lead to unnecessary panic, delayed response, or misallocation of resources,' said Vandekar. 'International regulations, including those by the International Civil Aviation Organization (ICAO), emphasise precise use of these terms to maintain safety and coordination during emergencies,' he said.
'By strictly adhering to international standards and guidelines in such situations, aircraft pilots ensure effective and flawless communication, which helps the ATC to swiftly and correctly deal with the situation to ensure the safety of passengers, crew, and aircraft,' said Vandekar.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to.
Jayashree Narayanan writes on fitness, health, food, culture and everything lifestyle. She is an alumnus of AJKMCRC, Jamia Millia Islamia and Kamala Nehru College, University of Delhi ... Read More
