Fault management system for gas turbine engines
View Patent ↗Disclosed herein is a “real time” Time Limited Dispatch (TLD) fault management system and method for evaluating the operational suitability of an engine's electronic control system. The TLD system disclosed herein uses a software algorithm to compute or predict the probability of mission success for a given upcoming mission length (e.g., two hours) and the time remaining to repair control system faults before dispatch is disallowed or the flight suspended, regardless of the probability of success.
1. A fault management method for a dual channel electronic engine control system, the method comprising the steps of:
a) providing an electronic engine control system having a first channel and a second channel, wherein each of the first and second channels have a plurality of components associated therewith each having a predicted failure rate, the components in the second channel being substantially identical to the components in the first channel;
b) designating, for each of the plurality of components in the first channel, which of the plurality of components in the second channel are single thread components required to cover a failure of that particular first channel component;
c) detecting whether any one of the plurality of components in the first channel have failed;
d) estimating a total failure rate based on the failure rates for all of the single thread components required to cover any failed components; and
e) predicting the time remaining to fix the electronic control system faults based on the total failure rate.
2. A fault management method as recited in claim 1 , wherein the step of estimating a total failure rate based on the failure rates for all of the single thread components includes summing the failure rates for all of the single thread components and failure rates for common prime reliable components.
3. A fault management method as recited in claim 1 , wherein the step of predicting the time remaining to fix the electronic control system faults based on the total failure rate includes the step of assigning a desired probability for maintaining normal engine control.
4. A fault management method as recited in claim 1 , further comprising the steps of:
a) establishing an estimated mission length;
b) comparing the estimated mission length to the predicted time remaining to fix the system faults; and
g) providing an go/no-go signal based on the comparison of the time remaining to fix the electronic control system faults to estimated mission length.
5. A fault management method as recited in claim 1 , further comprising the steps of:
a) detecting whether any of single thread components in the second channel have failed; and
b) providing a no-go signal if a single thread component in the second channel has failed.
6. A fault management method as recited in claim 1 , further comprising the steps of:
a) estimating a probability of mission success based on the total failure rate;
b) assigning a minimum probability of success for the mission; and
c) providing a no-go signal if the estimated probability of mission success does not exceed the assigned minimum probability of success.
7. A fault management method as recited in claim 1 , wherein prior to the step of predicting based on the total failure rate the time remaining to fix the electronic control system faults, the method further comprises the steps of:
a) designating for each of the plurality of components in the second channel which of the plurality of components in the first channel are single thread components required to cover a failure of that particular second channel component and maintain normal engine control;
b) detecting which of the plurality of components in the second channel have failed; and
c) estimating the total failure rate based on the failure rates for all of the single thread components in the first and second channels which are required to cover the failed first and second channel components.
8. A fault management method as recited in claim 1 , wherein the steps of detecting which of the plurality of components in the first channel have failed; estimating a total failure rate based on the failure rates for all of the single thread components in the second channel which are required to cover the failed first channel component; and predicting based on the total failure rate the time remaining to fix the electronic control system faults are preformed iteratively.
9. A fault management model for a dual channel electronic engine control system, the model comprising:
a) an electronic engine control system having a first channel and a second channel, wherein the first and second channels have a plurality of components associated therewith each having an assigned failure rate, the components in the second channel being substantially identical to the components in the first channel;
b) means for designating for each of the plurality of components in the first channel which of the plurality of components in the second channel are single thread components required to cover a failure of that particular first channel component;
c) means for detecting whether any of the plurality of components in the first channel have failed;
d) means for estimating a total failure rate based on the failure rates for all of the single thread components required to cover any failed components; and
e) means for predicting the time remaining to fix the electronic control system faults based on the total failure rate.
10. A fault management model as recited in claim 1 , wherein the means for estimating a total failure rate based on the failure rates for all of the single thread components includes means for summing the failure rates for all of the single thread components and failure rates for common prime reliable components.
11. A fault management model as recited in claim 1 , wherein the means for predicting based on the total failure rate the time remaining to fix the electronic control system faults includes means for assigning a desired probability for maintaining normal engine control.
12. A fault management model as recited in claim 1 , further comprising:
a) means for establishing an estimated mission length;
b) means for comparing the estimated mission length to the predicted time remaining to fix the system faults; and
c) means for providing a go/no-go signal based on the comparison of the time remaining to fix the electronic control system faults to estimated mission length.
13. A fault management model as recited in claim 1 , further comprising:
a) means for detecting whether any of the single thread components in the second channel have failed; and
b) means for providing a no-go signal if a single thread component in the second channel has failed.
14. A fault management model as recited in claim 1 , further comprising:
a) means for estimating a probability of mission success based on the total failure rate;
b) means for assigning a minimum probability of success for the mission; and
c) means for providing a no-go signal if the estimated probability of mission success does not exceed the assigned minimum probability of success.
15. A fault management model as recited in claim 1 , further comprising:
a) means for designating for each of the plurality of components in the second channel which of the plurality of components in the first channel are single thread components required to cover a failure of that particular second channel component;
b) means for detecting whether any of the plurality of components in the second channel have failed; and
e) means for estimating the total failure rate based on the failure rates for all of the single thread components in the first and second channels which are required to cover the failed first and second channel components.
16. A fault management method for electronic engine control systems, the method comprising the steps of:
a) providing an electronic engine control system having a first plurality of components for normal engine control and second plurality of components which are substantially redundant to the first plurality of components, each of the first and second plurality of components having an assigned failure rate;
b) designating for each of the first plurality of components which of the second plurality of components are single thread components required to cover a failure of that particular first component;
c) iteratively detecting whether any of the first plurality of components have failed;
d) iteratively estimating a total failure rate based on the failure rates for all of the single thread components required to cover the failed first plurality of components; and
e) iteratively predicting the time remaining to fix the electronic control system failure based on the total failure rate.
17. A fault management method as recited in claim 1 , wherein the step of iteratively estimating a total failure rate based on the failure rates for all of the single thread components includes summing the failure rates for all of the single thread components and failure rates for common prime reliable components.
18. A fault management method as recited in claim 1 , wherein the step of iteratively predicting the time remaining to fix the electronic control system failures based on the total failure rate includes the step of assigning a desired probability for maintaining normal engine control.
19. A fault management method as recited in claim 1 , further comprising the steps of:
a) establishing an estimated mission length;
b) comparing the estimated mission length to the iteratively predicted time remaining to fix the system failures; and
c) providing an go/no-go signal based on the comparison of the time remaining to fix the electronic control system failures to estimated mission length.
20. A fault management method as recited in claim 1 , further comprising the steps of:
a) detecting whether any of the single thread components in the second plurality of components have failed; and
b) providing a no-go signal if any single thread component in the second plurality of components has failed.
21. A fault management method as recited in claim 1 , further comprising the steps of:
a) estimating a probability of mission success based on the total failure rate;
b) assigning a minimum probability of success for the mission; and
c) providing a no-go signal if the estimated probability of mission success does not exceed the assigned minimum probability of success.
22. A fault management method as recited in claim 1 , wherein prior to the step of predicting based on the total failure rate the time remaining to fix the electronic control system failures, the method further comprises the steps of:
a) designating for each of the second plurality of components which of the first plurality of components are single thread components that are required to cover a failure of that particular component;
b) detecting whether any of the second plurality of components have failed; and
c) estimating the total failure rate based on the failure rates for all of the single thread components required to cover the failed first and second plurality of components.