Susan Michaelis

University of Stirling · Faculty of Health Sciences

Thermally degraded engine oil and hydraulic fluid fumes contaminating aircraft cabin air conditioning systems have been well documented since the 1950s. Whilst organophosphates have been the main subject of interest, oil and hydraulic fumes in the air supply also contain ultrafine particles, numerous volatile organic hydrocarbons and thermally degr...

Introduction: While there is strong interest in aircraft air quality in respect to COVID-19 and emissions into the environment, the concerns regarding oils and hydraulic fluids leaking into the aircraft air supply and cabin have yet to receive the same level of attention. This is despite considerable knowledge about this design problem first recogn...

Background Airline crew members report adverse health effects during and after inhalation exposure to engine oil fumes sourced to the air supply system onboard commercial and military aircraft. Most investigations into the causal factors of their reported symptoms focus on specific chemical contaminants in the fumes. The adverse health effects repo...

PurposeCase series on respiratory features of Aerotoxic Syndrome (AS). The term AS has been coined to describe the spectrum of clinical manifestations after aircraft fume events. Among these manifestations, neurological and respiratory symptoms are the most frequently reported complaints.Methods Three cases of AS with relevant respiratory features...

KEYWORDS crew health, organophosphate, regulations, cabin air, memorandum of understanding ABBREVIATIONS CAA Civil Aviation Authority OP Organophosphate MOU Memorandum of understanding ABSTRACT The paper explores a number of obstacles to and key approaches on the recognition and management of occupational health problems, relevant interactions and...

KEYWORDS occupational exposure limit, expose standards, hypoxic environment, bleed air ABBREVIATIONS TCP Tricresyl phosphate OEL Occupational exposure limit TLV Threshold limit value ABSTRACT The use of occupational exposure limits and threshold limit values in the aircraft environment is examined in relation to aircraft air supplies contaminated b...

Explores use and problems with exposure standards in aviation linked to cabin air quality and bleed air the value and validity of current occupational exposure limits and expose standards, and hypoxic environments.

The paper explores a number of obstacles to and key approaches on the recognition and management of occupational health problems, relevant inter-actions and possible multi-causality in the context of aircraft crew health and safety. The dominant approach has all too often been – ‘don’t look, don’t find, where is the problem?’ Control and removal of...

Introduction Since the 1950s pressurised aircraft cabin air has been drawn unfiltered from turbine jet engines as ‘bleed air’. Therefore emissions from engine oil seals leads to contamination of the breathable cabin air. The synthetic oils include a wide range of hazardous substances including the organophosphates, and a complex pyrolysed mixture....

On board aircraft, the common use of engine compressor, pressurised air to seal the oil bearing chamber and as a source for the cabin bleed-air supply provides a mechanism for low-level oil leakage in routine engine operations. This is of great concern and was discussed previously in this newsletter in a feature entitled ‘Oil bearing seals and airc...

We present strong evidence for the presence of aerosols of Nano-particles (also termed Ultrafine Particles (UFPs) in aerosol science) in the breathing air of pressurized aircraft using engine bleed air architecture. The physical and chemical nature of engine oils and the high temperatures attained in aircraft jet engines (up to 1,700°C in the oil c...

There are certification and airworthiness requirements relevant to the provision of clean breathing air in the crew and passenger compartments. There have been continuing reports and studies over the years regarding oil fumes in aircraft, including impaired crew performance. Oil fumes are viewed in varying ways ranging from rare seal bearing failur...

In-flight incidents called “Fume Events” are associated with a range of symptoms among those exposed, mostly among susceptible airline crew members. Despite currently ongoing ambient monitoring studies, there are no systematic investigations using clinical or human biomonitoring data to evaluate the direct impact of possible harmful substances on h...

From the 1950’s, aircraft were redesigned to provide pressurized cabin air directly from the compressor stage of the engine, known as bleed air. This allowed for the fuel consuming turbo compressors used prior to that date to be dispensed with. However, it also led to the exposure of aircrew and passengers to fugitive emissions from aircraft engine...

Background: Concerns related to adverse health effects experienced by aircrew exposed to aircraft contaminated air have been ongoing for over 6 decades. Unfiltered breathing air is supplied to the cabin via the engine compressor. The likelihood that oil leaking over the engine oil seals may enter the cabin air supply has prompted continuing debate...

Introduction Fumes produced by pyrolysed engine oils have been recognised to contaminate aircraft air supplies since 1953.1,2 The design and use of aircraft air supplies taken from the engine, provides a mechanism for lower level exposure in normal flight. The oils containing a range of hazardous substances including organophosphates, have been ass...

On board aircraft, the common use of engine compressor, pressurised air to seal the oil bearing chamber and as a source for the cabin bleed air supply provides a mechanism for low-level oil leakage in routine engine operations. Although this problem was identified in the 1950s with the advent of synthetic jet engine oils, the problem remains ongoin...

A broad overview of the subject is presented, covering all salient aspects including the technical history, a discussion of the compounds involved in the contamination, the frequency of occurrence, a survey of attempts to measure the contamination, safety considerations, health considerations, and possible technical solutions to the problem of cont...

This thesis examines the six-decade use of unfiltered aircraft bleed air, taken from jet engines to supply breathing air in the flight decks and passenger cabins of commercial and military transport aircraft. During this time, numerous flight safety issues and adverse effects from exposure to contaminated bleed air have been reported. The research...

Aircraft cabin air being supplied from the engines or APU is known to occasionally be contaminated with hydraulic fluids, engine oils, and pyrolysis products of these which need to be removed to ensure that the crew and passengers are not exposed to any contaminants. One way of achieving this is to filter these contaminants out of the outside air b...

Aircraft air supply contamination from leaking oil and hydraulic fluids has along history in commercial aviation. There is awide range of aviation legislation covering the required processes to be followed when this type of defect occurs, including reporting, maintenance procedures, airworthiness requirements, crew fitness for flight and emergency...

The issue of aircraft air contamination due to oils and hydraulic fluids leaking into the aircraft air supply is aknown problem in the aviation industry. There are arange of regulations that are in place to ensure all cases of fume contamination are reported and therefore investigated. However, there is strong evidence that the reporting system to...

The cabin of an airplane is aspecialised working environment and should be considered as such. The oils and hydraulics used in airplane engines are toxic, and specific ingredients of such materials are irritating, sensitising and neurotoxic. If oil or hydraulic fluids leak out of engines, this contamination may be in the form of unchanged oil/fluid...

A survey of health symptoms was undertaken in pilots who were members of the British Airline Pilots Association flying the Boeing 737, Boeing 757 and Airbus A320. Six hundred questionnaires were sent out to members, and 106 pilots responded. Survey respondents were predominantly male (104/106) and many had extensive flying experience. With regard t...

The concerns that were brought to the Australian Federation of Air Pilots regarding air quality problems revealed a number of operational and OHS issues. This prompted the design and conduct of a survey of symptoms in members who fly BAe 146 aircraft in Australia. A total of 19 pilots and two flight attendants responded. Survey respondents showed h...