Medical emergencies, whether minor or major in nature, frequently occur 33,000 feet up in the air. In the US, medical emergencies occur on around 50 commercial flights a day. 

The number of passengers travelling by air is increasing, with the International Air Transport Association (“IATA”) predicting that 7.2 billion passengers will travel by air in 2035, a near doubling of the 3.8 billion air travellers in 2016. This, combined with an aging population who are more mobile than ever before, and advances in medicine making air travel possible for those with medical conditions, is likely to lead to an increase in medical emergencies on board. 

The key difficulty when looking at medical emergencies in the air and the potential legal repercussions arising, is the huge number of variables at play: different airlines with different procedures, different staff with differing skills, different training, different passengers on board (sometimes medically trained passengers are on board, sometimes they are not), different equipment requirements, different nationalities often with language barriers, pre-existing medical histories, contraindications to treatment, and the list goes on. 

Medical emergencies in the aviation context present a challenge for carriers; practically, financially and legally. Staff must be trained, equipment must be supplied and maintained, and clear procedures must be in place. 

What is a medical emergency?

It is a simple fact of life that people become unwell; but with an increase in air travel comes an increased risk that a passenger may become unwell whilst up in the air. A passenger may be struck down with an acute illness, creating a practical problem of caring for that passenger whilst keeping them segregated from other passengers to prevent the spread of infection. Alternatively, a passenger may require medical attention as a result of a pre-existing condition flaring up or somehow being exacerbated by the stress or conditions of flying. 

The most common types of in-flight medical emergencies are syncope (temporary loss of consciousness from a sudden fall in blood pressure), gastrointestinal complaints and respiratory symptoms. Common symptoms experienced by passengers include dizziness, shortness of breath, nausea, vomiting, chest pains and headaches. These can be directly correlated with the conditions on board and the actual experience of flying. These minor medical situations can and should be anticipated by carriers. However, such situations can be (relatively) straightforward to deal with by utilising medicines on board and by crew activating basic first aid training.

The environment on board an aircraft is unusual with reduced pressure, which is of particular significance for passengers with cardiovascular or pulmonary pathology, affecting respiration. In addition, the physical space constraints can cause medical problems, an issue well ventilated in the courts through the DVT litigation.

However, a medical situation on board can rapidly descend into an emergency with fatal consequences where a passenger suffers, for example, a heart attack, seizure, stroke or asthma attack, or even goes into premature labour. Such medical emergencies are a cause of concern as the ‘passenger-patient’ will require medical treatment and possible diversion of the flight. There are practical space constraints and limited medical equipment on board. There is also the added need to manage other passengers who may witness harrowing medical scenarios. 

When illness or injury occurs on board, the crew are the first line of response and their actions can be the difference between life and death. Training of crew is vital: they suddenly have to be able to spot whether a passenger is drunk and unresponsive, or suffering a major brain haemorrhage; whether a passenger has acute appendicitis or just ate something dodgy at the holiday buffet. It is a huge responsibility and one which does not naturally fit into the role of cabin flight attendant. Situational based training with problem solving medical scenarios is therefore recommended, rather than a purely academic approach to learning procedure and the contents of a medical kit. 

When training crew members, it must be remembered that passengers will have their own medical history which may complicate any treatment required, particularly if the passenger is uncommunicative and travelling alone. This may lead to a simplistic approach necessitated by the urgency of an unknown situation and the lack of information available. 

However, crew members are not completely alone in dealing with medical emergencies on board. ‘MedAire’ was established in 1985 to provide assistance to carriers in preparing for and coping with medical emergencies. As part of this service, ‘MedLink’ was created to provide a ‘call a friend’ option to crew members, except this ‘friend’ is a qualified emergency doctor with an understanding of the environment on board and the equipment available. MedLink is the world’s first global emergency response centre for aviation providing a direct link to ground medical staff via the aircraft satellite phone, radio or the aircraft communications addressing and reporting system. These doctors on the ground can provide guidance to crew members and assist with diversion decisions. It is a 24 hours a day, 7 days a week service with doctors able to communicate in over 140 languages. It is certainly a service that saves lives and one which should be utilised by the crew where appropriate.

The law of 'accident'

In terms of liability for a medical emergency on board, the key question is whether there was an ‘accident’ under Article 17 of the Montreal Convention 1999 (“MC99”). This article does not seek to focus on this legal topic but a brief outline is required in order to highlight the potential for legal consequences if proper procedure and training is not in place.

A carrier will be liable for death or bodily injury to a passenger if the accident which caused the death or injury took place on board the aircraft, or in the course of embarking or disembarking. ‘Accident’ was defined by the US Supreme Court in the case of Air France v Saks to be: ‘an unexpected or unusual event or happening that is external to the passenger’. Therefore, in simple terms, if a passenger has a heart attack or suffers a stroke, this would, appear to be internal to the passenger and not an ‘accident’. 

However, difficulties may arise where the passenger has reacted to an external event which is unusual or unexpected in the circumstances (for example, a bump to the head following violent turbulence, resulting in a neurological complaint), or if the carrier’s own reaction to a passenger’s medical emergency is regarded as an ‘accident’ under this definition (i.e. the crew fail to follow procedure).

In the case of Olympic Airways v Husain, the carrier’s reaction to the claimant’s asthma (in failing to move him into a non-smoking seat) was considered to be unexpected and unusual and therefore an accident under MC99. The court also stated obiter that a carrier’s failure to react to a passenger developing an adverse medical condition may amount to an accident; however, this suggestion that a pure omission can amount to an accident under Article 17 has received judicial criticism.

Nevertheless, Husain highlights the importance of staff training to ensure that a medical emergency is dealt with in an expected and usual way in order to minimise future legal repercussions.

Further, clear procedures are needed to ensure medical conditions are not missed and that each situation is dealt with appropriately and in line with standard practice. The problem is that ‘standard practice’ does not exist. There is no statutory or binding guidance indicating an industry standard for reacting to medical emergencies on board; there is no ‘gold standard’ for carriers to adhere to. 

Therefore, the crew need to be trained and clear guidance needs to be in place to reduce the level of criticism that can be directed at a carrier where decisions are made in relation to a patient’s health. If a carrier is able to point to a guideline that each crew member is trained on and show that a passenger was treated in accordance with that guidance, in difficult circumstances, then it will be easier to argue that the actions taken were usual and expected. 

Given the potential liability under MC99 and the potential damage to a carrier’s reputation, medical emergency guidance, training and equipment should aim to meet the highest of standards.

Guidance and medical equipment on board 

There is limited international guidance in the area of medical emergencies and equipment on-board aircraft. 

The UK Civil Aviation Authority does not classify a medical emergency as an ‘emergency’ for the purposes of their generic guidance on handling emergencies. It will be classified as an emergency only if the pilot declares it as such, and then the usual guidance applies: aviate, navigate and communicate (see CAP 745 Aircraft Emergencies). Furthermore, the decision whether to divert a flight due to a medical emergency on board rests with the pilot. 

There is an International Civil Aviation Organisation (“ICAO”) Standard (which is mandatory) for on board medical supplies and this requires that an aircraft is equipped with ‘accessible and adequate medical supplies’ including one or more first aid kit. If the aircraft is to carry more than 100 passengers on a sector length of more than two hours, then a medical kit is required for the use of medical doctors or other qualified persons in treating inflight medical emergencies. However, the types of medical supplies to be carried within each kit are contained in nonmandatory recommended practices and guidance material; therefore, medical kits can vary hugely between carriers. 

The ICAO recommendations are supported and should be complied with despite their lack of mandatory force.

The closest there is to an industry standard is in the form of the first aid and emergency kits recommended by the Aerospace Medical Association (“AsMA”) and the International Air transport Association (“IATA”), and endorsed by the International Academy of Aviation and Space Medicine, the American Osteopathic Association, the American College of Emergency Physicians and the American Medical Association. Both kits have been approved by the chief of ICAO, subject to the Council’s approval which is expected to be forthcoming. 

AEDs on board aircraft 

Focusing on the emergency medical kit, there is no legal requirement to carry an Automatic External Defibrillator (“AED”). An AED is a device that gives a high energy electric shock to the heart and is used when someone is in cardiac arrest. AEDs can be frequently found in public places, such as shopping centres or train stations. 

Many airlines carry AEDs on board their aircraft. However, it is not mandatory because, according to ICAO guidance, only a very small number of passengers are likely to benefit from the carriage of an AED and therefore it is a decision for the carrier based on the duration of sector lengths and the number of passengers carried.

Click here to view the table.

However, it is well known that the risk of a cardiac event may increase due to the cabin environment, for example, reduced oxygen pressure in the cabin, disruption of circadian rhythms, and apprehension of the passenger. If a cardiac event occurs, any delay in starting resuscitation and using a defibrillator to deliver a shock when needed will reduce the passenger’s chance of survival. It is estimated that the number of sudden deaths from cardiac events during scheduled flights is actually greater than the number caused by aircraft accidents. Survival of cardiac arrest without the use of an AED is extremely unlikely due to the time that it takes to divert and land the aircraft to obtain the treatment needed.

Indeed the European Aviation Safety Agency recommends that AEDs should be on any aircraft which is capable of carrying more than 30 passengers and travelling more than 60 minutes away from medical assistance on the ground.

Thus, carriers should carefully consider the use of AEDs despite the lack of legal requirement, particularly considering the growing use of AEDs on airlines around the world which may make it possible to argue that an aircraft without an AED is operating unusually and unexpectedly, triggering potential liability under MC99. 

In the US, the Federal Aviation Administration (“FAA”) requires all US registered commercial aircraft weighing 7,500 pounds or more and serviced by at least one flight attendant to carry an AED and an enhanced medical kit. This kit is based on recommendations by the AsMA. Under the FAA regulations, a flight may not take off if it is missing the medical kit or an AED and flight attendants may only use equipment or medication under the direction of a licensed medical provider. They may use the first aid kit for minor situations without such supervision. 

It is clearly not practicable to provide the same equipment and level of medical care on board as one would expect to receive in a hospital. But, as far as possible, passengers should have access to appropriate medical equipment and well trained cabin crew proficient in first aid and lifesaving procedures. 

Is there a doctor on board?

In addition to the equipment on board and well trained crew, carriers may take advantage of medically trained passengers on board. 

The existence of a doctor on board may come as a huge relief for cabin crew in dealing with a complicated medical emergency; however, the very involvement of a doctor can cause difficulties. For example, a non-emergency specialist may be a qualified doctor and hold himself out as a medical professional but may not necessarily be competent to deal with a patient in cardiac arrest when compared with, for example, an Accident and Emergency consultant. This simple example highlights that it is crucial that crew, in requesting assistance from a medically qualified passenger, enquire as to the passenger’s specific medical expertise to ensure that they are aware of the limits of that passenger’s medical competency. 

Some airlines have ingeniously harnessed the expertise of medical professionals travelling on board their aircraft, for example, Lufthansa set up a ‘Doctor on board’ programme in 2009. Doctors sign up to the programme and receive air miles, a handbook on aviation medicine and in-flight medical emergencies as well as other promotional items. Austrian Airlines have also signed up to the scheme. As part of the programme, Lufthansa save the details and expertise of each professional when they sign up so that if a medical emergency occurs on board, the flight crew can approach them specifically for assistance. These doctors are covered by third-party insurance taken out by the airline for this particular purpose. Furthermore, Lufthansa offers aviation medical courses for their doctor members. This approach is a welcome development within aviation medicine and could save lives. Other carriers could adopt a similar programme by asking passengers to declare any medical expertise when booking their flight (verified with the relevant ID). 

The Good Samaritan in the UK

In the UK there is no legal obligation to intervene or give assistance by way of a ‘Good Samaritan’ act; for example, a doctor is not legally obliged to assist an individual suffering a heart attack in the street, unless such a duty is contracted for. However, there may be a moral or ethical duty to assist.

Most medical insurance providers will continue to provide cover in the event that its insured doctor assists as a Good Samaritan, including the Medical Protection Society (“MPS”) and the Medical Defence Union (“MDU”). This is important as an ‘off duty’ doctor flying home from a holiday abroad will owe a duty of care to the passenger-patient as soon as they intervene to assist cabin crew. 

A doctor assisting on board will be held to the standards of a reasonable practitioner in the normal way, although the General Medical Council has suggested the standard of care expected is the same as what a reasonable practitioner would have done in that situation. 

In contrast, in France, Germany and Japan, there is a requirement or duty to assist in an emergency unless doing so would endanger your own life. There is also a possibility that Article 2 of the European Convention on Human Rights (the right to life) might provide grounds for action if there were consequences arising from non-involvement of a doctor. Carriers should keep this in mind as some medically trained passengers may feel obliged to assist in a medical emergency on board. 

There is a distinct lack of legal authority on the relationship between a Good Samaritan, patient and a carrier. It is common sense that a medically trained individual should refuse to intervene and act as a Good Samaritan if they are outside of their competency or incapacitated (for example, they have consumed alcohol during the flight or just before). Ideally, crew should also ask for evidence of qualifications and see identity documentation.  

In practice, the MDU and the MPS have never encountered a case (in either the aviation or non-aviation context) of a healthcare professional being sued after providing emergency assistance as a Good Samaritan. 

If a medical emergency does occur on board, and a medically trained passenger is assisting, they would be advised to:

Provide assistance, within the scope of their professional competence, where the individual regards it  is their ethical or professional duty to do so;

Seek the patient's informed consent prior to any treatment (if possibile);

Not perform treatment if not equipped to do so in that situation or if not competent to do so, and instead leave it to other professionals (e.g. other medically trained passengers, crew or medical staff on the ground);

Make a detailed note of any incident; and;

Inform their insurer of  any incidents of this nature.

Medically trained passengers in the US

In the US, the Aviation Medical Assistance Act 1998 applies to carriers and individuals who are sued within the US. It states that a carrier shall not be liable for damages in any action arising out of performance of the air carrier in obtaining or attempting to obtain the assistance of a passenger in an in-flight emergency. This includes the acts or omissions of a passenger assisting (if not an employee or agent of the carrier) and if the carrier acts in good faith in believing the passenger is medically qualified. 

The individual assisting with the medical emergency, under this legislation, is not liable unless they are guilty of gross negligence or wilful misconduct. 

Therefore, US lawmakers have defined the duties of a doctor who intervenes in this context and have decided that a professional is to be held harmless by law, even where they are negligent, provided they are not grossly negligent. 


One of the key challenges is the lack of shared data on aviation medical emergencies and minor incidents. 

Airline specific studies give some indication, for example, in one year (1998-1999) a British Airways study showed that 3,386 medical cases were reported, which was approximately 1 case in every 11,000 passengers. In another study between 2003 and 2008, one airline (based in Hong Kong) had 4,068 reported cases within a 5 year period, and out of those cases 46 resulted in diversions (1.1%) and 30 in cardiac arrest or death (0.7%). However, there is a need for better data collection by individual carriers and globally with a central registry of medical emergencies which could inform future practice, assist with training of crew and ultimately enhance passenger safety. 

Carriers would do well to adopt risk management procedures and plan for all eventualities, as far as reasonably possible, given the almost infinite variables involved with air travel. In an ideal world, there would be an authoritative guide with every possible medical emergency that could develop on board but this is an impossible task and therefore general principles should be applied. 

Carriers should consider following the medical equipment guidance recommended by AsMA and IATA, as set out above, and consider the use of AEDs on all flights, irrespective of distance and passenger capacity.