The mnemonic A-B-C-D-E—Airspeed, Best landing site, Checklist, Declare, Execute—works here, as it would in an actual emergency landing situation.

In the context of in-flight medical emergencies, flight crews use the ABCD acronym to stabilize a passenger before a potential emergency landing. A stands for Airway: ensuring the passenger’s throat is clear and they can breathe. B stands for Breathing: checking for respiratory rate and providing supplemental oxygen if needed. C stands for Circulation: checking for a pulse and managing any severe bleeding or signs of shock. D stands for Defibrillation or Disability: using the on-board AED (Automated External Defibrillator) if the heart has stopped, or assessing the passenger’s neurological "disability" (level of consciousness). In 2026, cabin crews are highly trained in this sequence. If a passenger fails to stabilize after the ABCD check, the Captain will consult with ground-based medical professionals (such as MedAire) to decide if an "Emergency Diversion" is necessary. This protocol ensures that life-saving measures are prioritized while the logistics of landing the plane are handled.