The report describes evaluation of two prototype phase dilution rebreathing masks as compared to an open port rebreathing mask design. Human subjects wearing the prototype masks and engaged in three minute periods of rest and exercise were exposed to altitudes of 14,000, 18,000, 25,000, 30,000 and 34,000 feet in an altitude chamber. Each subject was instrumented to obtain a variety of physiological parameters including end expiratory gas composition, blood oxygen saturation (ear oximetry), ECG, and respiratory rate (impedance pneumograph). Oxygen flow and system pressure as provided by an automatic constant-flow regulator were also determined. The automatic constant-flow regulator when used in conjunction with either of the prototype phase dilution rebreather test masks and proper orifices maintained the subjects' indicated blood oxygen saturations equal to or in excess of their ground level (1,273 feet) baselines. With the same oxygen flow rates the prototype porous and dilution valve masks provided higher tracheal oxygen partial pressures than the open port masks at all altitudes tested during rest and exercise. The prototype phase dilution rebreather masks appear to be more efficient since at the same flow rates a greater amount of oxygen was derived from the supply and less oxygen lost to the ambient environment as compared to the open port type mask. (Author).

Human error is cited as a major cause in over 70% of accidents, andit is widely agreed that a better understanding of humancapabilities and limitations - both physical and psychological -would help reduce human error and improve flight safety. This book was first published when the UK Civil AviationAuthority introduced an examination in human performance andlimitations for all private and professional pilot licences. Nowthe Joint Aviation Authorities of Europe have published a newsyllabus as part of their Joint Aviation Requirements for FlightCrew Licensing. The book has been completely revised and rewritten to takeaccount of the new syllabus. The coverage of basic aviationpsychology has been greatly expanded, and the section on aviationphysiology now includes topics on the high altitude environment andon health maintenance. Throughout, the text avoids excessive jargonand technical language. "There is no doubt that this book provides an excellent basicunderstanding of the human body, its limitations, the psychologicalprocesses and how they interact with the aviation environment. I amcurrently studying for my ATPL Ground Exams and I found this bookto be an invaluable aid. It is equally useful for those studyingfor the PPL and for all pilots who would like to be reminded oftheir physiological and psychological limitations." –General Aviation, June 2002