Airplane echelon comprehensive evaluation model

Abstract

The invention discloses an aircraft echelon comprehensive evaluation model, which relates to the technical field of aircraft use condition evaluation and comprises the following indexes: an index I: a service life reserve and maintenance stop rate index Q1; the index is used for evaluating the conditions that the total remaining service life of aircrafts of the same type is not lower than 40% and the maintenance stopping rate is not higher than 15% within a certain time period. The aircraft echelon control and optimization model algorithm is designed by using the achievement of the aircraft echelon control and optimization theory, and the aircraft echelon control and optimization model algorithm is designed according to the aircraft echelon control and optimization strategy in combination with the actual situation of the aircraft echelon of each unit of the flight fleet by using the aircraft echelon control and optimization tool. According to the method, an aircraft overhaul echelon scheme, an aircraft annual echelon use scheme, an aircraft month echelon use scheme and an aircraft flight day echelon use scheme can be automatically generated, a manager can conveniently control and use aircraft echelon, the problems of centralized overhaul, centralized regular inspection, centralized life reaching and the like of aircraft equipment are solved, and the use effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft scientific use evaluation, and in particular to an aircraft echelon comprehensive evaluation model. Background Art

[0002] As the flight time of the flight fleet increases, the concentration of aircraft overhauls and the crowded queues of aircraft waiting to be repaired in overhaul plants have led to a significant reduction in the aircraft integrity rate, seriously affecting the completion of the flight missions of the flight fleet. The annual flight training tasks of the flight fleet have shown an increasing trend year by year. Due to the high intensity of flight training and the small number of aircraft, it is inevitable that specific inspections such as aircraft scheduled inspections and engine replacements will be concentrated, affecting the completion of annual flight training.

[0003] At present, many mature aviation safety evaluation systems have been formed abroad; domestic research on aviation safety evaluation issues mainly adopts fuzzy comprehensive evaluation method, multi-attribute decision-making method, Bayesian network evaluation method and other evaluation methods. These studies have the phenomenon of focusing on the macro and neglecting the micro; at the same time, there are few research results on grassroots aircraft maintenance safety quality evaluation, and a widely used and effective safety quality comprehensive evaluation system and application software system has not yet been formed. The corresponding safety and quality indicators mostly remain in isolated and decentralized analysis. Therefore, it is very necessary to establish a grassroots aircraft echelon comprehensive evaluation system.

[0004] Aiming at the specific problems in the current aircraft succession plan formulation, we use the results of the aircraft succession control and optimization theory summarized and studied by the scientific research team for many years to design a model algorithm for aircraft succession control and optimization. According to the aircraft succession control and optimization strategy and combined with the actual aircraft succession of each unit in the flight fleet, we use the aircraft succession control and optimization tool to automatically generate aircraft overhaul succession plans, aircraft annual succession usage plans, aircraft monthly succession usage plans, and aircraft flight day succession usage plans, which are convenient for managers to control and use aircraft successions, and can effectively improve the aircraft succession control capabilities and prevent the occurrence of problems such as centralized scheduled inspections and centralized overhauls of aircraft.

[0005] It should be introduced in detail so that the agent can understand the technical content. If the prior art comes from patents, journals, or books, the source should be provided. The technical status of the closest similar or similar products before the invention is patented should be specifically described. The specific content may involve the structure, the relationship between the components, the process, etc. The analysis of the background technology is more important. It is usually based on patent literature retrieval, scientific and technological journals, and products that have been disclosed on the market. Avoid subjective assumptions.

[0006] Patent CN114004013A has been retrieved, which is an auxiliary decision-making method, storage medium and terminal device for annual tiered use of aircraft. The decision-making method includes: 1. Determine the distribution matrix of the remaining life of a single aircraft; 2. Determine whether the total time of annual flight training missions is not greater than the total remaining life of the fleet aircraft; 3. Determine the remaining life tiered line equation; 4. Obtain the preliminary annual planned use time of a single aircraft; 5. Calculate the remaining life ratio of the fleet at the end of the year; 6. Determine whether the remaining life ratio is less than the remaining life ratio threshold; 7. Determine the final annual planned use time of a single aircraft.

[0007] Now we have retrieved the journal article "A Comprehensive Evaluation Method for Military Aircraft Quality". This method uses the analytic hierarchy process and expert scoring method to calculate the weight of each indicator, and uses the set pair analysis method to establish a comprehensive military aircraft quality evaluation model.

[0008] The existing technology has the following problems:

[0009] Patent CN114004013A only considers the remaining life of a single aircraft, and does not consider the impact of important factors such as the use process and overhaul on the aircraft's cascade use from the perspective of the entire fleet.

[0010] The evaluation indicators used in the journal article "A Comprehensive Evaluation Method for Military Aircraft Quality" only consider three aspects: aircraft status, mission status, and maintenance management. The evaluation indicators are not comprehensive enough, and the relevant indicators are difficult to extract and calculate in actual use, thus affecting the actual evaluation results.

[0011] In view of the above problems, the present invention proposes to use the aircraft service life reserve and maintenance grounding rate index Q1, the aircraft remaining life ladder uniformity index Q2, the aircraft stunt time ratio consistency index Q3, the aircraft parking interval uniformity index Q4 and the aircraft scheduled inspection and overhaul plan execution index Q55 indicators, fully considering the impact of aircraft service life, remaining life and overhaul conditions on aircraft use efficiency, and constructing an aircraft ladder comprehensive evaluation algorithm model. By establishing an aircraft ladder comprehensive evaluation algorithm model, it is possible to effectively evaluate the ladder use of various types of aircraft, improve effective ladder control and optimize ladder control plans, and provide reliable data support for flight fleets and overhaul plants to plan overhaul tasks in advance. Summary of the invention

[0012] The present invention provides an aircraft echelon comprehensive evaluation model to solve the problems raised in the above background technology.

[0013] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0014] An aircraft echelon comprehensive evaluation model, the aircraft echelon comprehensive evaluation model includes the following indicators:

[0015] Indicator 1: Service life reserve and maintenance grounding rate indicator Q1; this indicator is used to evaluate the situation that the total remaining service life of the same type of aircraft is not less than 40% and the maintenance grounding rate is not higher than 15% within a certain period of time;

[0016] Indicator 2: Remaining life tier uniformity index Q2; this index is used to evaluate the uniformity of the remaining service life tier arrangement of an aircraft at a certain moment;

[0017] Indicator 3: Parking interval uniformity index Q4; this index is used to evaluate the extent of corrosion damage caused by ground parking of aircraft within a certain period of time;

[0018] Indicator 4: Scheduled inspection and overhaul plan execution index Q5; this indicator is used to evaluate the degree to which scheduled inspection and overhaul tasks of the flight fleet are executed according to the plan;

[0019] Indicator 5: Determination of the weight of each indicator in the evaluation system; After the indicator table of the evaluation system is given, it is also necessary to determine its importance in the aircraft cascade use control and give the corresponding weight value in order to conduct a comprehensive evaluation; the indicator system has various attributes, and the AHP method is considered to determine the weight of each indicator. The specific process includes the following steps:

[0020] A1: Construct a pairwise comparison judgment matrix:

[0021] A2: The square root method is used to determine the importance vector and relative weight;

[0022] A3: consistency check;

[0023] Indicator six: Mathematical model of evaluation index system; Based on indicators one to five, the mathematical model Q of the comprehensive evaluation index system for aircraft cascade utilization control can be established.

[0024] Preferably, the indicator 1 mainly considers the number of days T during which the remaining total life of the aircraft is not less than 40% within the specified time period. d1 , the number of days during the specified period when the aircraft maintenance grounding rate is not higher than 15% T d2 ; The number of days that both conditions are met is T d0 It can be expressed as:

[0025] T d0 =T d1 ∩T d2

[0026] Assume: The total number of days in the specified time period is T D , then the aircraft service life reserve and maintenance grounding rate index Q1 can be expressed as:

[0027]

[0028] It can be seen from the Q1 expression that the larger its value is, the better the aircraft meets the use requirements; conversely, the worse the situation is.

[0029] Preferably, in the second indicator, it is assumed that: the fleet X has a total of N aircraft of type X, and their average prescribed fatigue life is T h hours, the remaining service life of each aircraft is t1, t2, …, t N , let △ = T h / N represents the ideal interval of the remaining service life of each aircraft, and the aircraft remaining service life gradient uniformity index Q2 can be expressed as:

[0030]

[0031] From the expression of Q2, it can be seen that the larger its value is, the more evenly the remaining life intervals of each aircraft are close to the ideal interval, that is, the better the echelon condition is. When the remaining life intervals of each aircraft are equal to the ideal interval Δ, that is, Q2 = 100%, it is considered that the echelon condition is the best at this time; conversely, the worse the aircraft's echelon condition is, when the remaining life of each aircraft is exactly the same, that is, Q2 = 0, it is considered that the aircraft's echelon condition is the worst or there is no echelon.

[0032] Preferably, in the third indicator, the larger the Q4 value, the more uniform the aircraft parking interval (or the frequency of aircraft use), which means that the corrosion damage is smaller in the same time period; conversely, the smaller the Q4 value, the greater the corrosion damage. Suppose: there are N aircraft of type X in fleet X, and the number of times the i-th aircraft is parked for more than one week in a certain time period is k i The number of days of parking each time is d1, d2, …, d ki , refer to the method of establishing Q3 index; then the parking interval uniformity of the i-th aircraft is q i It can be expressed as:

[0033]

[0034] Among them, E di and S di They represent the mean and standard deviation of the number of days the i-th aircraft is parked during the period; the mean of the parking uniformity of each aircraft is taken as the parking interval uniformity of the entire fleet, so the mathematical expression of indicator Q4 is:

[0035]

[0036] Preferably, in the fourth indicator, the larger the Q5 value, the more reasonable the arrangement of the aircraft echelon use by the equipment support department; otherwise, it means that the arrangement of the aircraft echelon use is not reasonable enough, resulting in the failure to execute the scheduled inspection, overhaul and other tasks as planned; suppose: in a certain period of time, the X fleet has a total of M tasks such as aircraft scheduled inspection and overhaul, among which there are m items that are not executed as planned without special circumstances, then the aircraft scheduled inspection and overhaul plan execution index Q5 can be expressed as

[0037]

[0038] Preferably, the construction of a pairwise comparison judgment matrix is:

[0039] In order to quantify the results of the pairwise comparison judgment of the importance of each indicator, it is necessary to use the scale definition given in Table 1. According to the meaning given by each scale, firstly construct the pairwise comparison judgment matrix of the importance of the five indicators of the comprehensive evaluation index system;

[0040] By comparing and judging the five indicators, namely, the aircraft service life reserve and maintenance grounding rate index Q1, the aircraft remaining life ladder uniformity index Q2, the aircraft stunt time ratio consistency index Q3, the aircraft parking interval uniformity index Q4, and the aircraft scheduled inspection and overhaul plan execution index Q5, a pairwise comparison judgment matrix A is constructed.

[0041] Preferably, the square root method determines the importance vector and relative weight:

[0042] The importance vector W is commonly used in the AHP method i And the relative weight of each indicator W i 0 There are four main methods: summation method, square root method, characteristic root method and least squares method. The square root method is used here, and the mathematical formulas are as follows:

[0043]

[0044] After calculation, the importance vector of the five indicators of the aircraft cascade use control comprehensive evaluation index system is

[0045] W=(1,2.6052,1.6438,0.6084,0.3839) T

[0046] Its relative weight is

[0047] W 0 =(0.16,0.42,0.26,0.10,0.06).

[0048] Preferably, the consistency check:

[0049] Since the evaluation index system has 5 evaluation indicators, that is, n = 5, and after calculating λ max =5.068, therefore, its consistency index The corresponding average random consistency index RI = 1.12, so the consistency ratio can be obtained

[0050]

[0051] That is, it passes the consistency test.

[0052] Preferably, in the sixth indicator, the mathematical expression is:

[0053]

[0054] Where Q represents the final score of aircraft cascade use control; Q i represents the score of the i-th indicator i=1,2,…,n; w i Represents the relative weight of the i-th indicator, and the weight vector is w = W 0 ; n represents the number of indicators in the comprehensive indicator system. In this indicator system, n=5.

[0055] Due to the adoption of the above technical solution, the present invention has the following technical advances compared with the prior art:

[0056] The present invention provides an aircraft echelon comprehensive evaluation model. The achievements of aircraft echelon control and optimization theory are used to design a model algorithm for aircraft echelon control and optimization. According to the aircraft echelon control and optimization strategy and in combination with the actual conditions of aircraft echelons of various units in a flight fleet, an aircraft echelon control and optimization tool is used to automatically generate an aircraft overhaul echelon plan, an aircraft annual echelon use plan, an aircraft monthly echelon use plan, and an aircraft flight daily echelon use plan, which is convenient for managers to control and use aircraft echelons, solves the problems of centralized overhaul, centralized scheduled inspection, and centralized life expectancy of aircraft equipment, and has a good actual use effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION

[0058] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0059] like Figure 1 As shown, an aircraft echelon comprehensive evaluation model includes the following indicators:

[0060] Indicator 1: Service life reserve and maintenance grounding rate indicator Q1; this indicator is used to evaluate the situation that the total remaining service life of the same type of aircraft is not less than 40% and the maintenance grounding rate is not higher than 15% within a certain period of time;

[0061] Indicator 2: Remaining life tier uniformity index Q2; this index is used to evaluate the uniformity of the remaining service life tier arrangement of an aircraft at a certain moment;

[0062] Indicator 3: Parking interval uniformity index Q4; this index is used to evaluate the extent of corrosion damage caused by ground parking of aircraft within a certain period of time;

[0063] Indicator 4: Scheduled inspection and overhaul plan execution index Q5; this indicator is used to evaluate the degree to which scheduled inspection and overhaul tasks of the flight fleet are executed according to the plan;

[0064] Indicator 5: Determination of the weight of each indicator in the evaluation system; After the indicator table of the evaluation system is given, it is also necessary to determine its importance in the aircraft cascade use control and give the corresponding weight value in order to conduct a comprehensive evaluation; the indicator system has various attributes, and the AHP method is considered to determine the weight of each indicator. The specific process includes the following steps:

[0065] A1: Construct a pairwise comparison judgment matrix:

[0066] A2: The square root method is used to determine the importance vector and relative weight;

[0067] A3: consistency check;

[0068] Indicator six: Mathematical model of evaluation index system; Based on indicators one to five, the mathematical model Q of the comprehensive evaluation index system for aircraft cascade utilization control can be established.

[0069] Among them, indicator 1 mainly considers the number of days T during the specified period when the remaining total life of the aircraft is not less than 40%. d1 , the number of days during the specified period when the aircraft maintenance grounding rate is not higher than 15% T d2 ; The number of days that both conditions are met is T d0 It can be expressed as:

[0070] T d0 =T d1 ∩T d2

[0071] Assume: The total number of days in the specified time period is T D , then the aircraft service life reserve and maintenance grounding rate index Q1 can be expressed as:

[0072]

[0073] It can be seen from the Q1 expression that the larger its value is, the better the aircraft meets the use requirements; conversely, the worse the situation is.

[0074] Among them, in indicator 2, suppose: there are N aircraft of X type in fleet X, and their average prescribed fatigue life is T h hours, the remaining service life of each aircraft is t1, t2, …, t N , let △ = T h / N represents the ideal interval of the remaining service life of each aircraft, and the aircraft remaining service life gradient uniformity index Q2 can be expressed as:

[0075]

[0076] From the expression of Q2, it can be seen that the larger its value is, the more evenly the remaining life intervals of each aircraft are close to the ideal interval, that is, the better the echelon condition is. When the remaining life intervals of each aircraft are equal to the ideal interval Δ, that is, Q2 = 100%, it is considered that the echelon condition is the best at this time; conversely, the worse the aircraft's echelon condition is, when the remaining life of each aircraft is exactly the same, that is, Q2 = 0, it is considered that the aircraft's echelon condition is the worst or there is no echelon.

[0077] Among them, in the third indicator, the larger the Q4 value, the more uniform the aircraft parking interval (or the frequency of aircraft use), which means that the corrosion damage is smaller in the same time period; conversely, the smaller the Q4 value, the greater the corrosion damage. Suppose: there are N aircraft of type X in fleet X, and the number of times the i-th aircraft is parked for more than one week in a certain period of time is k. i The number of days of parking each time is d1, d2, …, d ki , refer to the method of establishing Q3 index; then the parking interval uniformity of the i-th aircraft is q i It can be expressed as:

[0078]

[0079] Among them, E di and S di They represent the mean and standard deviation of the number of days the i-th aircraft is parked during the period; the mean of the parking uniformity of each aircraft is taken as the parking interval uniformity of the entire fleet, so the mathematical expression of indicator Q4 is:

[0080]

[0081] Among them, in the fourth indicator, the larger the Q5 value, the more reasonable the arrangement of the aircraft echelon use by the equipment support department; on the contrary, it means that the arrangement of the aircraft echelon use is not reasonable enough, which leads to the failure to execute the scheduled inspection and overhaul tasks as planned; suppose: in a certain period of time, the X fleet has a total of M tasks such as aircraft scheduled inspection and overhaul, among which there are m items that are not executed as planned without special circumstances, then the aircraft scheduled inspection and overhaul plan execution index Q5 can be expressed as

[0082]

[0083] Among them, construct a pairwise comparison judgment matrix:

[0084] In order to quantify the results of the pairwise comparison judgment of the importance of each indicator, it is necessary to use the scale definition given in Table 1. According to the meaning given by each scale, firstly construct the pairwise comparison judgment matrix of the importance of the five indicators of the comprehensive evaluation index system;

[0085] Table 1 Judgment matrix scale definition

[0086] Scale meaning 1 The two elements are equally important 3 Compared with the two factors, the former is slightly more important than the latter. 5 Compared with the two factors, the former is obviously more important than the latter. 7 Compared with the two factors, the former is more important than the latter. 9 Compared with the two factors, the former is extremely more important than the latter. 2,4,6,8 The middle value of the above adjacent judgments reciprocal The importance of the latter compared to the former

[0087] By comparing and judging the five indicators, namely, the aircraft service life reserve and maintenance grounding rate index Q1, the aircraft remaining life ladder uniformity index Q2, the aircraft stunt time ratio consistency index Q3, the aircraft parking interval uniformity index Q4, and the aircraft scheduled inspection and overhaul plan execution index Q5, a pairwise comparison judgment matrix A is constructed.

[0088] Table 2 Pairwise comparison judgment matrix of the importance of five indicators

[0089] A <![CDATA[Q1]]> <![CDATA[Q2]]> <![CDATA[Q3]]> <![CDATA[Q4]]> <![CDATA[Q5]]> <![CDATA[Q1]]> 1 1 / 3 1 / 2 2 3 <![CDATA[Q2]]> 3 1 2 4 5 <![CDATA[Q3]]> 2 1 / 2 1 3 4 <![CDATA[Q4]]> 1 / 2 1 / 4 1 / 3 1 2 <![CDATA[Q5]]> 1 / 3 1 / 5 1 / 4 1 / 2 1

[0090] Among them, the square root method determines the importance vector and relative weight:

[0091] The importance vector W is commonly used in the AHP method i And the relative weight of each indicator W i 0 There are four main methods: summation method, square root method, characteristic root method and least squares method. The square root method is used here, and the mathematical formulas are as follows:

[0092]

[0093] After calculation, the importance vector of the five indicators of the aircraft cascade use control comprehensive evaluation index system is

[0094] W=(1,2.6052,1.6438,0.6084,0.3839) T

[0095] Its relative weight is

[0096] W 0 =(0.16,0.42,0.26,0.10,0.06).

[0097] Among them, consistency check:

[0098] Since the evaluation index system has 5 evaluation indicators, that is, n = 5, and after calculating λ max =5.068, therefore, its consistency index The corresponding average random consistency index RI = 1.12, so the consistency ratio can be obtained

[0099]

[0100] That is, it passes the consistency test.

[0101] Among them, in indicator six, the mathematical expression is:

[0102]

[0103] Where Q represents the final score of aircraft cascade use control; Q i represents the score of the i-th indicator i=1,2,…,n; w i Represents the relative weight of the i-th indicator, and the weight vector is w = W 0 ; n represents the number of indicators in the comprehensive indicator system. In this indicator system, n=5.

[0104] Working principle of the present invention: The aircraft echelon comprehensive evaluation model has a total of 5 indicators, namely, aircraft service life reserve and maintenance grounding rate indicator Q1, aircraft remaining life echelon uniformity indicator Q2, aircraft stunt time ratio consistency indicator Q3, aircraft parking interval uniformity indicator Q4 and aircraft scheduled inspection and overhaul plan execution indicator Q5. By comparing and judging these 5 indicators, the overall situation of aircraft use in the flight fleet can be comprehensively and comprehensively evaluated from the perspective of the fleet.

[0105] After the indicators of the evaluation system are given, it is also necessary to determine their importance in the aircraft cascade use control and give corresponding weight values ​​for comprehensive evaluation. The present invention determines the weight of each indicator using the AHP method, specifically including (1) constructing a judgment matrix for pairwise comparison; (2) using the square root method to determine the importance vector and relative weight; (3) consistency test method.

[0106] On the basis of theoretical research and practical comparison, the influence of aircraft service life, remaining life and overhaul on aircraft performance is fully considered. The five indicators in the above key point 1 are combined with the weights of each indicator in the evaluation system to establish a more comprehensive and reasonable mathematical model of the evaluation index system, and a comprehensive evaluation algorithm model for aircraft echelons is proposed. This model can effectively evaluate the echelon usage of various types of aircraft, improve effective echelon control and optimize echelon control schemes, and provide reliable data support for flight fleets and overhaul plants to plan overhaul tasks in advance.

[0107] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An aircraft echelon comprehensive evaluation model, characterized by: The aircraft echelon comprehensive evaluation model includes the following indicators: Indicator 1: Service life reserve and maintenance grounding rate indicator Q1; this indicator is used to evaluate the situation that the total remaining service life of the same type of aircraft is not less than 40% and the maintenance grounding rate is not higher than 15% within a certain period of time; Indicator 2: Remaining life tier uniformity index Q2; this index is used to evaluate the uniformity of the remaining service life tier arrangement of an aircraft at a certain moment; Indicator 3: Parking interval uniformity index Q4; this index is used to evaluate the extent of corrosion damage caused by ground parking of aircraft within a certain period of time; Indicator 4: Scheduled inspection and overhaul plan execution index Q5; this indicator is used to evaluate the degree to which scheduled inspection and overhaul tasks of the flight fleet are executed according to the plan; Indicator 5: Determination of the weight of each indicator in the evaluation system; After the indicator table of the evaluation system is given, it is also necessary to determine its importance in the aircraft cascade use control and give the corresponding weight value in order to conduct a comprehensive evaluation; the indicator system has various attributes, and the AHP method is considered to determine the weight of each indicator. The specific process includes the following steps: A1: Construct a pairwise comparison judgment matrix: A2: The square root method determines the importance vector and relative weight; A3: consistency check; Indicator six: Mathematical model of evaluation index system; Based on indicators one to five, the mathematical model Q of the comprehensive evaluation index system for aircraft cascade utilization control can be established.

2. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: The first indicator mainly considers the number of days T during the specified period when the remaining total life of the aircraft is not less than 40%. d1 , the number of days during the specified period when the aircraft maintenance grounding rate is not higher than 15% T d2 ; The number of days that both conditions are met is T d0 It can be expressed as: T d0 =T d1 ∩T d2 Assume: The total number of days in the specified time period is T D , then the aircraft service life reserve and maintenance grounding rate index Q1 can be expressed as: From the Q1 expression, we can see that the larger its value is, the better the aircraft meets the use requirements; On the contrary, the situation will be worse.

3. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized in that: In the second indicator, it is assumed that: Fleet X has a total of N aircraft of type X, and their average specified fatigue life is T h hours, the remaining service life of each aircraft is t1, t2, …, t N , let △ = T h / N represents the ideal interval of the remaining service life of each aircraft, and the aircraft remaining service life gradient uniformity index Q2 can be expressed as: From the expression of Q2, it can be seen that the larger its value is, the more evenly the remaining life intervals of each aircraft are close to the ideal interval, that is, the better the echelon condition is. When the remaining life intervals of each aircraft are equal to the ideal interval Δ, that is, Q2 = 100%, it is considered that the echelon condition is the best at this time; conversely, the worse the aircraft's echelon condition is, when the remaining life of each aircraft is exactly the same, that is, Q2 = 0, it is considered that the aircraft's echelon condition is the worst or there is no echelon.

4. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized in that: In the third indicator, the larger the Q4 value, the more uniform the aircraft parking interval (or the frequency of aircraft use), which means that the corrosion damage is smaller in the same time period; conversely, the smaller the Q4 value, the greater the corrosion damage. Suppose: there are N aircraft of type X in fleet X, and the number of times the i-th aircraft is parked for more than one week in a certain time period is k. i The number of days of parking each time is d1, d2, …, d ki , refer to the method of establishing Q3 index; then the parking interval uniformity of the i-th aircraft is q i It can be expressed as: Among them, E di and S di They represent the mean and standard deviation of the number of days the i-th aircraft is parked during the period; the mean of the parking uniformity of each aircraft is taken as the parking interval uniformity of the entire fleet, so the mathematical expression of indicator Q4 is:

5. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: In the fourth indicator, the larger the Q5 value, the more reasonable the arrangement of aircraft echelon use by the equipment support department; on the contrary, it means that the arrangement of aircraft echelon use is not reasonable enough, which leads to the failure to perform scheduled inspections, overhauls and other tasks as planned; Assume that: in a certain period of time, the X fleet has a total of M tasks such as aircraft inspection and overhaul, among which there are m tasks that are not executed as planned without special circumstances. Then the aircraft inspection and overhaul plan execution index Q5 can be expressed as 6. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: The construction of pairwise comparison judgment matrix: In order to quantify the results of the pairwise comparison judgment of the importance of each indicator, it is necessary to use the scale definition given in Table 1. According to the meaning given by each scale, firstly construct the pairwise comparison judgment matrix of the importance of the five indicators of the comprehensive evaluation index system; By comparing and judging the five indicators, namely, the aircraft service life reserve and maintenance grounding rate index Q1, the aircraft remaining life ladder uniformity index Q2, the aircraft stunt time ratio consistency index Q3, the aircraft parking interval uniformity index Q4, and the aircraft scheduled inspection and overhaul plan execution index Q5, a pairwise comparison judgment matrix A is constructed.

7. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: The square root method determines the importance vector and relative weight: The importance vector W is commonly used in the AHP method i And the relative weight of each indicator W i 0 There are four main methods: summation method, square root method, characteristic root method and least squares method. The square root method is used here, and the mathematical formulas are as follows: After calculation, the importance vector of the five indicators of the aircraft cascade use control comprehensive evaluation index system is W＝(1,2.6052,1.6438,0.6084,0.3839) T Its relative weight is W 0 ＝(0.16,0.42,0.26,0.10,0.06)。 8. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: The consistency check: Since the evaluation index system has 5 evaluation indicators, that is, n = 5, and after calculating λ max =5.068, therefore, its consistency index The corresponding average consistency index RI = 1.12, so the consistency ratio can be obtained That is, it passes the consistency test.

9. The aircraft echelon comprehensive evaluation model according to claim 1 is characterized by: In the sixth indicator, the mathematical expression is: Where Q represents the final score of aircraft cascade use control; Q i represents the score of the i-th indicator i=1,2,…,n; w i Represents the relative weight of the i-th indicator, and the weight vector is w = W 0 ; n represents the number of indicators in the comprehensive indicator system. In this indicator system, n=5.

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