“Mayday mayday mayday Thomson 253H, engine failure, continuing northwesterly, inbound towards Wallasey”Flight crew of Thomson 253H
This radio message was sent from Thomson253H on 29.04.2007. The aircraft had 233 persons on board. You might imagine the situation this aircraft was in and the level of distress they were facing. Luckily, not all radio messages indicate an absolute emergency.
What levels of distress exist?
Pan-pan is an urgency call indicating a problem on board but there is no immediate danger to anyone’s life or the aircraft itself. With Pan-pan ATC and also rescue providers on ground are informed and can mentally prepare for a worsening scenario. ATC will support the flight crew with all information they need and other traffic calls will be downgraded in priority.
Whenever an aircraft crew sends a message like this, all attention needs to be on them as a mayday call indicates a life-threatening emergency. To clearly distinguish between other calls or noises (mishearing), the word mayday is repeated three times (as in the first example above). As an alternative to the word mayday, the crew may also use the term “declaring an emergency”.
Escalation / De-escalation
However the situation develops, the status of an aircraft might change. Whenever the situation is under control, both mayday and Pan-pan can be ended by the flight crew that declared the situation. If Pan-pan was declared and the situation gets worse, the status can be set to mayday afterwards, see example of SR111, where the status from Pan-pan was escalated to an emergency some minutes later:
01.14.18 – „Swissair one eleven heavy is declaring Pan Pan-pan. We have uh smoke in the cockpit, uh request (deviate), immediate return uh to a convenient place, I guess uh Boston.“
01.24.45 – „Swissair one eleven heavy is declaring emergency“
01.24.46 – [Second voice overlap] (Roger) „we are between uh twelve and five thousand feet we are declaring emergency now at ah time ah zero one two four.“
You might have read about accidents or incidents, where no emergency call was sent and air traffic control was not aware about the problems. You might wonder why the crew did not inform air traffic control and ask for support. One possible explanation is the guideline of
Aviate – Navigate –Communicate
The priorities for the flight crew are clearly standardized. First; keep your aircraft flying, followed by navigating your aircraft. Only then, communication will be established. This is to avoid errors during an emergency, as humans tend to focus on details and set wrong priorities. It seems so simple, but it’s easy to forget when you get busy in the cockpit.
What did happen to Thomson 253H?
After declaring the emergency, the flight crew managed to safely land the aircraft. No passenger or crew was injured.
Interesting links to this topic:
- amazon.com (Cover Photo)