Aircraft Decompression with Installed Cockpit Security Door

Abstract

A zero-dimensional model of cockpit and cabin decompression with cockpit security door is presented. The hinged panels in the security door were modeled to account for the pressure-equalization dynamics in the case of cockpit decompression. A comprehensive isentropic and isothermal theoretical analysis is presented with many closed-form and asymptotic solutions. New analytical estimates for the total decompression time and the pressure half-time were derived. The simulations for typical corporate and large-transport-category airplanes with different cabin geometries, discharge coefficients, rupture cross-sectional areas, pressure altitudes, and cabin altitudes have been obtained. The case in which the cockpit depressurizes first and its effect on the cabin decompression and on the security door integrity has been extensively studied. The recently required cockpit doors may be hazardous for flight crew in the case cockpit depressurizes first and other venting and blowout panels malfunction or are too slow to respond. The resulting pressure differential between the cockpit and the cabin can create instantaneous forces in excess of 80 kN on the cockpit security door. In addition, this puts the crew in danger due to explosive decompression on the time scale of 100 ms and increases the possibility of the security door being blown out of the frame.

Achieving global range in future subsonic and supersonic airplanes

“…High-temperature resistant lightweight structural materials for subsonic and particularly for the supersonic cruisers are needed.  Stronger and lighter structures for 6,000-ft pressure-cabin standard (Daidzic & Simones, 2010). This requires the maximum pressure differentials in excess of 10 psi while allowing for altitudes of 50,000 ft, and higher, for aircraft in cruise and up to aerodynamic and/or propulsion ceilings, while avoiding the coffin-corner.…”

“…East and West) faster than any modern high-subsonic airplane would achieve with a single fuel-stop. British-French Concorde, unfortunately no longer in operational service, cruise-climbed (about 50 fpm) at M=2.0 and altitudes between FL500 and FL600, thus staying just below the Armstrong limit (Daidzic & Simones, 2010). The Breguet's integral range equation was known for a long time.…”

An algebraic model of high-altitude aircraft decompression and emergency descent

“…This model was designed mostly for low-speed GA aircraft and does not incorporate wave drag. An exhaustive review of references addressing aircraft decompressions is given in Daidzic and Simones (2010). Also various analytical and numerical polytropic expansion models were used to simulate decompressions in small and large airplanes.…”

Global Optimized Isothermal and Nonlinear Models of Earth’s Standard Atmosphere

“…Two important heights/altitudes exist in Earth's atmosphere relevant to the aviation and aerospace industries. One is the Armstrong (physiological) limit (named after Harry George Armstrong) which is located at about 19.2 km (63,000 ft) and designates the height at which the total atmospheric pressure drops to less than 63 hPa (0.91 psi) at which the unprotected (unpressurized) human bodily fluids would start evaporating/boiling considering the normal average human body temperature of about 37 0 C (Daidzic & Simones, 2010). About 70% of human body is water and many different bodily fluids have essential life-preservation functions.…”

“…About 70% of human body is water and many different bodily fluids have essential life-preservation functions. In reality, the blood is circulating under somewhat higher (gage) pressure and it would take some time and even lower atmospheric pressures to start ebulism and anoxia (Daidzic & Simones, 2010). This is the main reason pressurized suits must be worn above 50,000 feet (aeromedical "onset of space") unless the aircraft is built to stricter space standards.…”