Detection of uncommanded and uncontrollable high thrust events

Abstract

Methods and systems for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft are described. The method comprises detecting an abnormal engine response as a function of a fuel flow error, the fuel flow error indicative of a presence of excess thrust; in response to detecting the fuel flow error, detecting a UHT event based on the excess thrust and as a function of a threshold; and accommodating the UHT event when the UHT event is detected.

1 . A method for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft, the method comprising:
 detecting an abnormal engine response as a function of a fuel flow error, the fuel flow error indicative of a presence of excess thrust;   in response to detecting the fuel flow error, detecting a UHT event based on the excess thrust and as a function of a threshold; and   accommodating the UHT event when the UHT event is detected.   
     
     
         2 . The method of  claim 1 , wherein detecting the UHT event comprises:
 determining an estimated excess thrust as an actual net thrust minus a reference net thrust;   determining an estimated excess thrust impulse by integrating the estimated excess thrust over a period of time; and   comparing the estimated excess thrust impulse to the threshold.   
     
     
         3 . The method of  claim 2 , wherein the actual net thrust is calculated from a measured engine speed, and the reference net thrust is calculated from a reference engine speed as a function of a thrust lever angle position. 
     
     
         4 . The method of  claim 1 , wherein accommodating the UHT event comprises triggering a fuel shutoff valve. 
     
     
         5 . The method of  claim 1 , wherein the threshold is specific to an aircraft model. 
     
     
         6 . The method of  claim 2 , wherein the threshold comprises an upper and a lower limit, wherein the UHT event is detected when the estimated excess thrust impulse exceeds the upper limit, and the estimated excess thrust impulse is reset when the estimated excess thrust impulse falls below the lower limit for a predetermined time period. 
     
     
         7 . A system for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft, the system comprising:
 at least one processing unit; and   a non-transitory computer-readable memory having stored thereon program instructions executable by the at least one processing unit for:
 detecting an abnormal engine response as a function of a fuel flow error, the fuel flow error indicative of a presence of excess thrust; 
 in response to detecting the fuel flow error, detecting a UHT event based on the excess thrust and as a function of a threshold; and 
 accommodating the UHT event when the UHT event is detected. 
   
     
     
         8 . The system of  claim 7 , wherein detecting the UHT event comprises:
 determining an estimated excess thrust as an actual net thrust minus a reference net thrust;   determining an estimated excess thrust impulse by integrating the estimated excess thrust over a period of time; and   comparing the estimated excess thrust impulse to the second threshold.   
     
     
         9 . The system of  claim 8 , wherein the actual net thrust is calculated from a measured engine speed, and the reference net thrust is calculated from a reference engine speed as a function of a thrust lever angle position. 
     
     
         10 . The system of  claim 7 , wherein accommodating the UHT event comprises triggering a fuel shutoff valve. 
     
     
         11 . The system of  claim 7 , wherein the threshold is specific to an aircraft model. 
     
     
         12 . The system of  claim 8 , wherein the threshold comprises an upper and a lower limit, wherein the UHT event is detected when the estimated excess thrust impulse exceeds the upper limit, and the estimated excess thrust impulse is reset when the estimated excess thrust impulse falls below the lower limit for a predetermined time period. 
     
     
         13 . A non-transitory computer readable medium having stored thereon program code executable by a processor for detecting an uncommanded or uncontrollable high thrust (UHT) event in an aircraft, the program code comprising instructions configured for:
 detecting an abnormal engine response as a function of a fuel flow error, the fuel flow error indicative of a presence of excess thrust;   in response to detecting the fuel flow error, detecting a UHT event based on the excess thrust and as a function of a threshold; and   accommodating the UHT event when the UHT event is detected.   
     
     
         14 . The non-transitory computer readable medium of  claim 13 , wherein detecting the UHT event comprises:
 determining an estimated excess thrust as an actual net thrust minus a reference net thrust;   determining an estimated excess thrust impulse by integrating the estimated excess thrust over a period of time; and   comparing the estimated excess thrust impulse to the threshold.   
     
     
         15 . The non-transitory computer readable medium of  claim 14 , wherein the actual net thrust is calculated from a measured engine speed, and the reference net thrust is calculated from a reference engine speed as a function of a thrust lever angle position. 
     
     
         16 . The non-transitory computer readable medium of  claim 13 , wherein accommodating the UHT event comprises triggering a fuel shutoff valve. 
     
     
         17 . The non-transitory computer readable medium of  claim 13 , wherein the threshold is specific to an aircraft model. 
     
     
         18 . The non-transitory computer readable medium of  claim 14 , wherein the threshold comprises an upper and a lower limit, wherein the UHT event is detected when the estimated excess thrust impulse exceeds the upper limit, and the estimated excess thrust impulse is reset when the estimated excess thrust impulse falls below the lower limit for a predetermined time period.