Method of calculating oxygen required and system for monitoring oxygen supply and/or calculating flight level after emergency cabin decompression

Abstract

A system useable in a jet aircraft having installed therein a pressurized oxygen supply which feeds oxygen into the interior of the plane when it flies at high cabin altitudes, the system indicating the changing status of the supply as oxygen is drained therefrom. The system includes a pressure transducer coupled to the supply and means associated with the transducer to determine the lapse rate at which the pressure of the supply is reduced as oxygen is drained therefrom to yield a first signal representing this pressure lapse rate, and to concurrently determine the lapse rate at which the number of liters of oxygen in the supply is reduced as oxygen is drained therefrom to yield a second signal representing the liter lapse rate. These signals are applied to a microprocessor in whose data base is entered the total oxygen inventory of the supply and the oxygen demand of the plane in which the supply is installed. When oxygen is being drained from the supply, the microprocessor calculates and reads out the prevailing supply pressure, the number of liters remaining in the supply, and the time in hours and minutes remaining before the supply is exhausted based on the current rate of oxygen consumption. The invention provides both a method for calculating the oxygen required, as well as a real time monitoring and calculating system for emergency conditions. The invention is applicable to any pressurized gas system, such as for divers, compressed gas cooking or vehicles, therapeutic oxygen, and the like.

1. A system for determining a safe flight level in an aircraft having a pressurized oxygen supply, comprising:
 a pressure transducing system sending a data signal indicative of the pressure in the oxygen supply;  
 means for providing a data signal indicative of the amount of fuel in the aircraft;  
 computecomputer data storage for  maintaining aircraft engine performance data and equal time point (ETP) data between two predetermined diversion airports;  
 a computer processor receiving said pressure and fuel data and calculating (i) fuel usage versus time as a function of the engine performance data, (ii) oxygen usage versus time as a function of altitude, and (iii) ETP versus time as a function of altitude; and  
 a screen for graphically displaying at least one of (i), (ii), and (iii) superimposed , and optionally superimposing at least two of (i), (ii), and (iii) when said at least two are graphically displayed .  
 
     
     
       2. The system of  claim 1 , further comprising means for inputting to said computer data storage the number of crew members, the number of crew members on regulated oxygen, the number of passengers, and the number of passengers on therapeutic oxygen. 
     
     
       3. The system of  claim 1 , wherein the processor calculates and the screen displays the minimum safe flight level. 
     
     
       4. The system of  claim 1 , wherein the processor calculates and the screen displays the maximum safe flight level. 
     
     
       5. The system of  claim 1 , wherein the processor calculates and the screen displays an optimum safe flight level. 
     
     
       6. The system of  claim 3 , further comprising means for inputting the calculated value to an automatic pilot. 
     
     
       7. The system of  claim 4 , further comprising means for inputting the calculated value to an automatic pilot. 
     
     
       8. The system of  claim 5 , further comprising means for inputting the calculated value to an automatic pilot. 
     
     
       9. A jet aircraft having the system of  claim 1 . 
     
     
       10. The system of  claim 1 , further comprising means for inputting to said computer processor an amount of reserve fuel. 
     
     
       11. A method for determining a safe flight level in an aircraft having a pressurized oxygen supply, comprising:
 providing a computer processor with display and interface;  
 transducing the pressure in the pressurized oxygen supply and providing a signal to the computer indicative of the pressure;  
 providing as input to the computer at least one of (a) a transduced signal indicative of the amount of fuel in the aircraft and (b) a manually input value indicative of the amount of fuel in the aircraft and optionally a reserve fuel quantity;  
 storing as data aircraft engine performance data and equal time point (ETP) data between two predetermined diversion airports;  
 transducing the altitude of the aircraft and providing a signal to the computer indicative of the altitude;  
 calculating in said computer processor (i) fuel usage versus time as a function of the engine performance data, (ii) oxygen usage versus time as a function of altitude, and (iii) ETP versus time as a function of altitude; and  
 displaying on said computer display (i), (ii), and/or  and (iii), optionally superimposed , and superimposing at least two of (i), (ii), and (iii) when said at least two are graphically displayed.  
 
     
     
       12. The method of  claim 11 , wherein the fuel level input is a transduced signal. 
     
     
       13. The method of  claim 11 , comprising displaying (i), (ii), and (iii) superimposed. 
     
     
       14. The method of  claim 13 , comprising displaying only the operating window, if any, formed by (i), (ii), and (iii). 
     
     
       15. The method of  claim 11 , further comprising storing passenger and crew regulator oxygen data. 
     
     
       16. The method of  claim 11 , wherein (i), (ii), and (iii) are all displayed in different colors. 
     
     
       17. The method of  claim 16 , the operating window is displayed in a different color.