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Smiths Industries is to supply the head‐up display system for the Sea Harrier. The company will design, develop and make the electronic head‐up display and weapon aiming computer system for the latest version of the HS Harrier which will operate from Royal Navy ships.

AS air is a compressible fluid, a decrease of pressure occurs with increase of altitude (FIG. 1.) This change gives rise to anoxia or altitude sickness (due to lack of oxygen), expansion of the gas in ear or abdomen and ‘bends’ or decompression sickness. For these reasons (and also because of the low temperature and humidity) it is necessary to protect passengers intending to fly at high altitudes by placing them in a special cabin in which a suitable pressurized atmosphere can be maintained.

THE COMPLEXITY of modern pressurisation and air conditioning systems for jet aircraft have led increasingly to the practice of selecting a single contractor to design and integrate all of the components into a compatible system tailored to the mission requirements of the aircraft.

The purpose of this paper is to evaluate the ozone risk introduced by the mixing air-supply mode, displacement air-supply mode and personalized air-supply mode, respectively, in commercial aircraft cabins.

In this study, a computational fluid dynamics (CFD) model of aircraft cabin has been built to study the distribution of ozone mass fraction and the ozone surface deposition rate on passenger’s face and clothes under the three different air-supply modes, respectively. The distribution of ozone mass fraction has been obtained by calculating the mass concentration of ozone in different location. The ozone surface deposition rate on passenger’s face and clothes has been calculated according to the mechanism of the reactions between ozone and squalene, which is the primary reactant in human sebum.

By comparing the three air-supply modes, it was considered that the mixing air-supply mode made lower ozone concentration and ozone surface deposition risk in most area, but this was because of the thin air distribution in cabin. The displacement air-supply mode made an uneven distribution of ozone concentration and increased absorbing ozone risk in the breathing zone. The personalized air-supply mode was proper for avoiding ozone harm and making a comfortable air environment. The air supply from the inlet on seat back could not increase the ozone surface deposition risk on passenger’s face.

This paper provides the qualitative and quantitative analysis for ozone risk to the passengers under the different air-supply modes. Findings can provide some suggestions for the designers to optimize the air-supply mode of air distribution system for reducing passengers’ discomfort caused by high-altitude ozone introduction, such as breathing in too much ozone.

IN the February 1956 issue of AIRCRAFT ENGINEERING the Editor put forward the suggestion that the pressure cabins of civil aircraft might with advantage be made of reinforced plastics instead of aluminium alloy. He had in mind recent difficulties encountered in pressure cabin design, especially those arising from metal fatigue, or revealed as a result of fatigue investigations. Plastic materials, maintains the editor, may well lend themselves to pressure cabin construction and provide a means of overcoming many of the current difficulties of design.

PASSENGER cabins have to encompass such a wide range of customer options and facilities tailored to the duration of journeys and the size of the aircraft as well as providing the latest in advanced materials that the precise definition of an airline's requirements can be a task of some complexity. Always of the highest importance but achieving a greater significance than ever before because of recent events, safety and survival requirements in the cabin are the subject of current and future legislation to improve conditions in the event of an accident. Noise level is also a major consideration and passengers accustomed to ‘turbo‐fan’ environments have found propeller noise to be sometimes an unpleasant experience. With modern technology, this situation has gradually improved and current turboprop aircraft such as the new Fokker 50 not only use a Dowty‐Rotol propeller with low blade loading and low tip speed to reduce noise, but also make use of a ‘floating interior’. This means that the aircraft's interior is completely self‐contained and forms a shell which is flexibly attached to the fuselage by rubber mountings. By this means, any possibility of excitation of the shell by the vibrating fuselage structure is avoided.

INTEREST in the fatigue of cabins of transport aircraft has increased considerably in the last year or so. Fatigue tests on a complete aircraft, undertaken as part of the Comet accident investigation, gave indications that the fatigue life of pressure cabins could be more critical than had generally been supposed.

Water systems in civil aircraft, stimulated by passenger comfort needs, have grown to be a comprehensive and important part of aircraft engineering. In this article, following a review of the system types, the design features arc discussed in detail and emphasis has been placed on the functional and hygiene requirements, and on the need for simplicity and weight conservation. Attempts have been made to augment air‐borne water supplies by reclamation means, but these have not been too successful. Investigations should therefore continue into the ways and means of improving the utilization of existing ‘fixed’ capacity systems. Installation safety aspects are also discussed.

THE advantages which arise from the directness and speed of aircraft, and the high record for safety held by Air Lines like Imperial Airways, contribute to the increasing popularity of air travel. With many persons, however, the chief deterrent at present is understood to be the discomfort caused by the noise experienced, and there is no doubt that there are civil aircraft in use to‐day which are excessively noisy. Consequently attention has been directed recently in this and in other countries to suppressing the considerable noise to which passengers in aircraft cabins are usually subjected. The experiments are not yet completed, and it is not possible yet to answer all the questions that may arise. It is thought, however, that the following account of the trend of present results, as judged from recent work in the light of the writer's own experience, may be helpful in indicating the principles involved.

IN 1929 a subcommittee was formed, by the Aeronautical Research Committee, to investigate the subject of aircraft noise. Various aspects of the work have received attention, and the present paper is an attempt to summarise the general conclusions in a form suitable for the aircraft industry, without reference to the results of the investigations themselves.