Transport aircraft crew and decompression hazards: study of a positive pressure schedule

The protection of the transport aircraft crew against cabin decompression hazards at high altitude (Z less than 45,000 ft) (13,700 m) is achieved by positive pressure breathing (PPB). Currently, many PPB schedules are used. Our research was performed to propose a PPB schedule, using the hypothesis of a decompression at high altitude, including a stay at the flight level and an emergency descent at the rate of 15,000 ft.min-1. The measures were arterial oxygen saturation, heart rate, speech capabilities, and psychomotor performance. The tests were conducted up to 45,000 ft. They show that the best protection at 45,000 ft is afforded when the PPB is included between 2 and 2.5 kPa (15 to 18.75 mm Hg).