In the year ending 31 March 1999 British Airways carried 36.8 million passengers and there were 3386 reported in-flight medical incidents: about 1 per 11 000 passengers. Though 70% were managed by cabin crew without the assistance of an on-board health professional, in almost 1000 incidents doctors and nurses were asked to help with the management of ill passengers. This article discusses the conditions most likely to lead to the announcement “If there is a doctor of medicine on board the aircraft, would they please make themselves known to one of the cabin crew.” #### Summary points About three quarters of in-flight medical emergencies are managed by cabin crew The range of equipment and drugs on board varies but can be extensive Doctors who volunteer to help the crew manage an incident should remember to “do no harm” and practise within the limits of their training and knowledge The information provided is based primarily on British Airways' experience of in-flight medical incidents, as captured from crew reports and supplemented by feedback from assisting health professionals, and from discussions with other airline medical departments. The information on medical kits and equipment is based on the regulatory requirements of the Joint Aviation Authorities, the kits and equipment carried on all British Airways aircraft, and discussions with other airline medical departments. The passenger with chest pain presents the same diagnostic challenge as a patient on the ground. A careful history is important, but language barriers and the cabin environment …