The issue

A passenger on-board an aircraft travelling from Hong Kong to London begins to exhibit worrying symptoms a short time into the flight: fever, sweating, frequent coughing, head and body aches, diarrhoea and nausea. Within a brief period several other passengers begin to exhibit the same symptoms. Cabin crew are strained and passengers are beginning to get worried.

What are an air carrier's responsibilities during a global health emergency; and to what liability could it be exposed?

The outbreak of the Ebola virus in West Africa in 2014 served to place the fear of pandemic at the top of recent world headlines. Among the foremost concerns surrounding the outbreak was the possible spread of the virus through air travel.

However, Ebola is just one of many global public health issues demanding attention from the aviation industry; the continued monitoring of Middle East respiratory syndrome (MERS) and flu virus strains such as H1N1, vigilance to prevent the spread of diseases such as tuberculosis and hepatitis, and threatened use of biological terror agents, among other concerns, combine to make air travel and public health a pressing concern for the broader air transport industry.

Air carriers, specifically, are placed at the centre of these public health issues as a potential vector for the spread of communicable disease. International and national regulatory rules and protocols have been put in place for air carriers, along with strict internal air carrier policies; however, the possibility exists for air carrier liability in this area.

Current regulations

The World Health Organization leads the international effort in determining the level of risk posed by disease; and providing information and issuing regulations to manage spread of disease. National public health authorities implement those regulations and lead national response efforts. International and national aviation authorities work with health authorities to develop guidelines for the aviation industry. Airports and air carriers coordinate with all of the above to meet their obligations as a first line of defence against the spread of communicable disease posing a threat to global health.

World Health Organization (WHO)

In 2005, the WHO issued the second edition of the International Health Regulations (IHR) to regulate and coordinate the global management and control of the international spread of disease; the IHR went into effect in 2007 and establishes comprehensive rules to meet this goal. Among these rules is recognition of the importance points of entry, such as airports, play in controlling the spread of communicable disease. Part IV, Article 20 requires States to designate and certify airports according to strict guidelines based on prevention, detection, response and control of communicable disease. Further, Annex 5 allows for specific emergency measures to be put in place to control vector-borne diseases on aircraft.

International Civil Aviation Organization (ICAO)

Article 14 of the 1944 Convention on International Civil Aviation (the Chicago Convention) requires States "to take effective measures to prevent the spread by means of air navigation of cholera, typhus (epidemic), smallpox, yellow fever, plague, and such other communicable disease as the Contracting States shall from time to time designate".

ICAO works closely with WHO and other international health and aviation bodies to address the spread of communicable disease in aviation. The IHR provide the framework by which ICAO has developed Standards and Recommended Practices (SARPs) and supporting guidelines to ensure there is coordinated management and response across their specialised disciplines.

The aviation sector's primary role is to reduce the likelihood of individuals who have contracted a communicable disease from travelling outside the area of an outbreak. Generally speaking, this will include traveller screening procedures and medical assessments performed at airports.

However, air carriers also play a large role and there are ICAO SARPs and guidelines specific to areas of air carrier preparedness, including communications, response to in-flight illness, and aircraft cleaning.

International Air Transport Association (IATA)

IATA coordinates with WHO and ICAO to ensure that efforts and guidelines aimed at managing the spread of communicable disease and minimizing the effects on any affected countries and the air transport industry generally are adopted. IATA provides information to air carriers on best practices and their responsibilities, including development of an Emergency Response Plan and Action Checklist in line with WHO's recommendations for use by air carriers in the event of a public health risk.

National legislation

The United States, United Kingdom and most other nations have in place national public health legislation in line with the IHR and the recommendations of national public health authorities, including the Center for Disease Control in the US and Department of Health in the UK. The UK has proposed legislation, the Health Protection (Ships and Aircraft) Regulations, which would specifically address the spread of communicable disease on aircraft.

Air carrier procedures

Under the IHR and ICAO guidelines, there are general areas of preparedness which air carriers are recommended to have in place, and which are required in more detail by national legislation.


Air carriers should have a central contact for policy and operations, along with a designated position with the responsibility for implementing plans and capable of responding rapidly.

When the aircraft is at the airport: pre- and post-flight

Airports have primary responsibility for screening and managing passengers. However, air carriers should have general procedures for their ground-based passenger agents who may encounter a suspected instance of communicable disease. Further, air carriers should coordinate and cooperate with airports and local public health authorities.

In-flight illness

Perhaps the most vital area, and the one which may most directly lead to potential liability, is the occurrence of in-flight illness. Air carriers should put in place a system by which cabin crew are able to identify suspected cases of communicable disease and procedures for communicating with air traffic control in the event a communicable disease is suspected to be on board the aircraft.

Most importantly in terms of measures to prevent the further spread of communicable disease, air carriers should have a system for managing travellers suspected of having a communicable disease; this includes obtaining advice from and communicating with medical ground support, physical relocation and possible isolation of the traveller on the aircraft, proper medical supplies, clean up of areas occupied by the traveller, proper protective equipment, disposal of contaminated items, and personal hygiene measures.

Aircraft maintenance

Air carriers should have in place procedures for maintenance crew in respect of the aircraft ventilation systems. Adequate precautions should be established for the removal and disposal of air filters, frequent and proper filter replacement, and personal protective equipment and hygiene measures. There should also be procedures in place for the proper venting of waste tanks and removal of bird debris in the event of a bird strike.

Aircraft cleaning

The air carrier crew responsible for cleaning an aircraft following the suspected transport of a traveller with a communicable disease should be subject to robust response and protective procedures. The air carrier should establish these procedures in line with international and national public health authorities, including use of proper personal protective gear, personal hygiene measures, identification of all surfaces to be cleaned, use of proper cleaning products, and disposal of any potentially contaminated items.

Cargo and baggage handling

Air carriers should have policies and procedures in place to ensure cargo and baggage handlers practice proper personal hygiene as well as make available any other measures that may be deemed necessary (i.e. personal protective gear). Air carriers should also cooperate with public health authorities in respect of cargo and baggage inspection.


In the event of a communicable disease emergency, air carriers may be forced to operate with significantly reduced staff. If this is the case, air carriers should have protocols in place to prevent disruption to their services.

Potential air carrier liability

There is a very low risk of transmitting a communicable disease on board an aircraft. Cabin air quality is carefully controlled; since 1963, all commercial aircraft have employed the "bleed air" system in which compressed air is drawn through the engines and into the cabin. This recirculated air passes through HEPA (high-efficiency particulate air) filters which trap bacteria and viruses, and which are also employed in hospital operating rooms and intensive care units. Further, modern advances are being adopted, such as in the recently-introduced Boeing 787 Dreamliner in which fresh cabin air is pumped via air scoops on the side of the fuselage which then passes through HEPA filters and an additional gaseous filtration system.

However, there have been incidents of aircraft acting as a vector for the spread of communicable disease. In 1979, an aircraft was delayed on the ground for three hours; within 72 hours, 72 per cent of the passengers had become ill with influenza. The aircraft ventilation system was inoperative during the delay and was identified as the cause of the high contamination rate. In 2002, 20 people on an international flight were infected by a single severe acute respiratory syndrome (SARS) patient, some as far as seven rows from the infected passenger. There have also been several incidents of tuberculosis being spread aboard an aircraft.

Communicable disease may be transmitted between passengers as the result of direct contact or contact with parts of the aircraft which came into contact with an infected passenger. Highly contagious airborne diseases, such as influenza, are more likely to spread where an aircraft's ventilation system is not operating or is malfunctioning.

These instances can give rise to potential and in some cases actual liability exposure for air carriers.

Potential liability

There are a number of risk factors that could result in potential liability for air carriers. These could include, but are not limited to, a carrier's suspecting that a passenger is ill at check-in but taking no steps to medically assess the passenger's ability to fly, a passenger falling ill in-flight but cabin crew failing to isolate or otherwise take responsive measures, an aircraft crew failing to communicate with ground medical staff during an in-flight illness, an air carrier failing to notify and inform other passengers following a flight with a passenger subsequently determined to have flown while infected with a communicable disease, a carrier failing adequately to clean an aircraft, and, perhaps most importantly, passengers falling ill as a result of inoperable or defective aircraft equipment or systems.

However, there are two significant obstacles a passenger must overcome in order to establish liability, in that the passenger must show: (1) that the communicable disease was contracted during the carriage by air; and (2) that the transmission of the communicable disease constituted an "accident" within the meaning of Article 17 of the Montreal Convention.

The first hurdle requires a passenger to establish firmly that he contracted the disease during the period encompassed by the contract of carriage; that is, onboard the aircraft or during embarkation or disembarkation. This is a difficult evidentiary burden as contraction of a disease is not a readily obvious event; an air carrier could argue that the passenger contracted the disease at his hotel, during transport to or from the airport, at the airport or at any one of numerous places the passenger will have been before and after his carriage by air.

The second hurdle requires a more extensive examination.

Montreal Convention

Contracts of carriage by air, and any claims relating to them, are governed exclusively by the Montreal Convention 1999. Article 17 of the Convention provides that an air carrier "is liable for damage sustained in case of death or bodily injury of a passenger upon condition only that the accident which caused the death or injury took place on board the aircraft or in the course of any of the operations of embarking or disembarking". Therefore, there must be an "accident" before there can be liability, although the word "accident" is not defined by the Convention.

In Air France v Saks, the United States Supreme Court defined "accident" for the purposes of the Warsaw Convention as an "unexpected or unusual event or happening that is external to the passenger". Injuries which are the passenger's own "internal reaction to the usual, normal and expected operation of the aircraft" are not caused by an "accident" and therefore do not give rise to liability. The finding in Air France v Saks has been adopted or applied in most relevant jurisdictions, and applies equally in the context of the Montreal Convention.

In light of the above, if a communicable disease is spread on board an aircraft as the result of an unexpected or unusual event external to a passenger, an air carrier may find itself liable to passengers for the contraction of that disease. This may occur in several ways. The risk factors listed in the previous section could potentially be found by a court to constitute accidents if they occur in contravention of applicable regulations or air carrier systems.

Failure to operate necessary equipment or malfunctions or defects in aircraft equipment or systems may amount to an accident. This could include not turning on the air ventilation system while the aircraft is grounded during a delay, malfunctions or defects in the aircraft air ventilation or waste disposal systems, insufficient medical supplies or treatment, or inadequate communication with ground medical staff and air traffic control while on board during an in-flight illness.

In the US case of Dias v Transbrasil Air, it was asserted that a passenger contracted pneumonia (from which she subsequently died) as a result of the poor quality of the aircraft cabin air during a flight from Brazil to New York City. The court held that the "presence of air of such poor quality that it causes a passenger to develop a fatal respiratory disease" is an accident under the Convention.

Regulatory liability

Failure properly to follow the protocols put in place by the international and national aviation and public health authorities may present issues of potential regulatory liability.

In the United States, there are penalties for certain violations of public health regulations, including failure to notify authorities of any death or seriously ill person on board an aircraft.

The proposed Health Protection (Ships and Aircraft) Regulations, which seek to amend the Public Health (Control of Disease) Act 1984 in the UK, would contain provisions making it a criminal offence to provide false or misleading information or otherwise obstruct public health officials acting under the regulations. There is no clear definition of what specific actions would lead to an offence under these proposed regulations, but clearly an air carrier would have to cooperate fully with public health officials.

Future issues and potential future regulation

It is very likely that current regulations will evolve in response to changing public health threats, and air carriers will have to respond in turn. As worldwide air travel continues to expand, in terms of both total passenger numbers and the geographic locations served, the global threat of the spread of communicable disease by air transport increases. Air carriers must adopt procedures aligned with international and national regulations to respond to this threat, and be aware of the potential liabilities they may face.

Air Carrier Liability For The Spread Of Communicable Disease

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