A method for evaluating the availability of an aeroengine

Abstract

The application belongs to the technical field of aero-engines, and particularly relates to an aero-engine availability evaluation method. BM and an average standby time T SM ; step S2: average maintenance time T M and average delay time T DM ; step S3: taking the quotient of the sum of the average maintenance interval time T BM and the average standby time T SM and the sum of the average maintenance interval time T BM , the average standby time T SM , the average maintenance interval time T BM and the average standby time T SM as the availability A of the aero-engine, the application can evaluate the engine availability by using design parameters and field reliability evaluation parameters of similar batch production models, and the evaluation method is more accurate.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to an aero-engine availability assessment method. Background Technology

[0002] The existing technical solutions for assessing the availability of aero-engines only consider the following availability calculation formula:

[0003]

[0004] Among them: A a For availability, T Oi For working hours, T CMi For restorative repair time, T PMi For preventative maintenance time;

[0005] The algorithm does not consider assurance delays, such as the spare parts availability rate for each maintenance level in Level 3 maintenance. The estimated MTBF based on batch production models and the proportion of on-site / in-situ repairs are not considered in the corrective repair time estimation. These factors contribute to the poor accuracy of the calculation method. Summary of the Invention

[0006] To address the aforementioned problems, this application provides a method for assessing the availability of an aircraft engine, comprising:

[0007] Step S1: Obtain the mean time between maintenance (MTBG) of the aircraft engine. BM and average standby time T SM ;

[0008] Step S2: Obtain the mean time to repair (MTBL) M and average delay time T DM ;

[0009] Step S3: Calculate the mean maintenance interval T BM With average standby time T SM The sum of the mean maintenance interval T BM Average standby time T SM Mean time between repairs (T) BM and average standby time T SM The availability of the engine is represented by the quotient of the engine.

[0010] Preferably, the mean time to repair (MTBL) is T. M Including mean time to repair (M) CT and mean preventive maintenance time M PT .

[0011] Preferably, the mean repair time M CT The methods for determining this include:

[0012] Step S1: Obtain the annual early engine replacement rate (UERR), annual early replacement and return-to-factory rate (URR), and failure rate (FR) for similar aircraft engine models.

[0013] Step S2: Calculate the proportion of in-situ repair and maintenance frequency α of the aircraft engine when it is installed in the aircraft. The calculation formula is α=(FR-UERR) / FR;

[0014] Step S3: Calculate the mean repair time M CT Its calculation formula includes:

[0015] M CT = (1-α)×(T) cz +MTTR)+α×MTTR;

[0016] Where MTTR is the mean repair time for in-situ repair, T cz For engine detachment, reassembly, and recovery time.

[0017] Preferably, the mean time to repair (MTBL) is T. M The calculation formula is as follows:

[0018]

[0019] In the formula:

[0020] N C The total number of corrective repairs performed on the engine within a specified time period;

[0021] M PT Mean time for preventive maintenance;

[0022] N P This refers to the total number of preventative maintenance procedures performed on the engine within a specified timeframe.

[0023] Preferably, the mean time between repairs (MTBL) is T. BM The calculation formulas include:

[0024] Calculate the total number of engine repairs N within the specified time. M Total number of engine repairs N M This includes the number of corrective maintenance operations and the number of preventative maintenance operations.

[0025] Number of corrective maintenance operations = Engine overhaul interval / Mean Time Between Failures (MTBF); Number of preventive maintenance operations = Engine overhaul interval / Scheduled inspection cycle.

[0026] The engine mean maintenance interval T is calculated based on the following formula. BM ,

[0027]

[0028] In the formula, T O The engine's operating time within a specified period.

[0029] Preferably, the average standby time T is calculated. SM The methods include:

[0030] Calculate the daily standby time as T w T w =24-T D T D This refers to the engine's average daily operating time.

[0031] The ratio k of engine operating time to standby time is calculated using the formula: k = T D / T w ;

[0032] Calculate the average standby time T SM The calculation formula is:

[0033] Preferably, the average guaranteed delay time T DM This includes delays T caused by spare parts allocation and acquisition factors at the troop level. MLD The calculation formula is:

[0034] T MLD =(1-s)(p1t1+(1-p1)p2t2+(1-p2)(p3t3+(1-p3)t4);

[0035] In the formula: m is the probability that the engine can be repaired without the need for spare parts; p1 is the basic-level spare parts satisfaction rate; T1 is the average time to obtain spare parts at the basic level; P2 is the intermediate-level spare parts satisfaction rate; T2 is the average time to obtain spare parts at the intermediate level; P3 is the base-level spare parts satisfaction rate; T3 is the average time to obtain spare parts at the base level; T4 is the average time to configure spare parts at the base.

[0036] The advantages of this application include: the introduction of average warranty delay time and consideration of spare parts supply satisfaction rate make the calculation and evaluation more accurate.

[0037] This application proposes a method for estimating average failure repair time based on annual early replacement rate (UERR), annual early replacement return rate (URR), and failure rate (FR), which makes the evaluation method more accurate.

[0038] This application can use design parameters and field reliability assessment parameters of similar mass-produced models to assess engine availability, and the assessment method is more accurate. Attached Figure Description

[0039] Figure 1This is a flowchart of a preferred embodiment of the aircraft engine availability assessment method of this application. Detailed Implementation

[0040] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0041] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0042] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0043] As shown in the figure, to address the above problems, this application provides a method for assessing the availability of an aircraft engine, including:

[0044] Step S1: Obtain the mean time between maintenance (MTBG) of the aircraft engine. BM and average standby time T SM ;

[0045] Step S2: Obtain the mean time to repair (MTBL) M and average delay time T DM ;

[0046] Step S3: Calculate the mean maintenance interval T BM With average standby time T SM The sum of the mean maintenance interval T BM Average standby time T SM Mean time between repairs (T) BM and average standby time T SM The availability of the engine is represented by the quotient of the engine.

[0047] Availability A is the ratio of operational time to scheduled time. Considering the correlation between availability and reliability and maintainability indicators, it guides the design and analysis of the engine development process. Its calculation formula is as follows:

[0048] Preferably, the mean time to repair (MTBL) is T. M Including mean time to repair (M) CT and mean preventive maintenance time M PT .

[0049] Preferably, the mean repair time M CT The methods for determining this include:

[0050] Step S1: Obtain the annual early engine replacement rate (UERR), annual early replacement and return-to-factory rate (URR), and failure rate (FR) for similar aircraft engines;

[0051] Specifically, a) Annual Early Engine Replacement Rate (UERR): The number of times an engine is disengaged prematurely due to engine failure per thousand flight hours, i.e., Annual Early Engine Replacement Rate = Number of Early Engine Replacements in the Year / (Flight Hours in the Year / 1000).

[0052] b) Annual Early Replacement Rate (URR): The number of times an engine failure causes an early replacement or return to the factory per thousand flight hours. The annual early replacement rate is calculated as: Number of early replacements in the current year / (Flight hours in the current year / 1000).

[0053] c) Failure Rate (FR): The number of engine failures per thousand flight hours / (flight hours in the current year / 1000).

[0054] The equipment under development is evaluated by comparing data from similar models.

[0055] Step S2: Considering that most basic-level repair maintenance units can be repaired in situ when the engine is installed in the aircraft, the maintenance frequency of the engine does not need to be removed (i.e., it can be repaired in situ) is calculated. This is the proportion of in-situ repair maintenance frequency α of the aircraft engine when it is installed in the aircraft. The calculation formula is α=(FR-UERR) / FR.

[0056] Step S3: Considering maintenance activities during the service life, assuming each off-site corrective maintenance requires one engine removal and reassembly, the engine removal and reassembly recovery time T is calculated. cz Mean Time To Repair (MTTR) for in-situ repairs, frequency of in-situ repairs (α), and calculation of mean repair time (M). CT Calculate the mean repair time M CT Its calculation formula includes:

[0057] M CT = (1-α)×(T) cz +MTTR)+α×MTTR;

[0058] Where MTTR is the mean repair time for in-situ repair, T cz For engine detachment, reassembly, and recovery time.

[0059] Preferably, the mean time to repair (MTBL) is T. M The calculation formula is as follows:

[0060]

[0061] In the formula:

[0062] N C The total number of corrective repairs performed on the engine within a specified time period;

[0063] M PT Mean time for preventive maintenance;

[0064] N P This refers to the total number of preventative maintenance procedures performed on the engine within a specified timeframe.

[0065] Preferably, the mean time between repairs (MTBL) is T. BM The calculation formulas include:

[0066] Calculate the total number of engine repairs N within the specified time. M Total number of engine repairs N M This includes the number of corrective maintenance operations and the number of preventative maintenance operations.

[0067] Number of corrective maintenance operations = Engine overhaul interval / Mean Time Between Failures (MTBF); Number of preventive maintenance operations = Engine overhaul interval / Scheduled inspection cycle.

[0068] The engine mean maintenance interval T is calculated based on the following formula. BM ,

[0069]

[0070] In the formula, T O The engine's operating time within a specified period.

[0071] Preferably, the engine mean standby time is the standby time corresponding to the engine mean maintenance interval under specified operating conditions. The engine mean standby time is calculated based on the daily number of aircraft sorties and average flight hours, the conversion relationship between engine operating time and flight hours, to determine the ratio of daily engine operating time to standby time. The engine mean standby time is then calculated based on this ratio, resulting in the mean standby time T. SM The methods include:

[0072] Calculate the daily standby time as T w T w =24-T D T D This refers to the engine's average daily operating time.

[0073] The ratio k of engine operating time to standby time is calculated using the formula: k = T D / T w ;

[0074] Calculate the average standby time T SM The calculation formula is:

[0075] Preferably, the average guaranteed delay time T DM This includes delays T caused by spare parts allocation and acquisition factors at the troop level. MLD The calculation formula is:

[0076] T MLD =(1-s)(p1t1+(1-p1)p2t2+(1-p2)(p3t3+(1-p3)t4);

[0077] In the formula: m is the probability that the engine can be repaired without the need for spare parts; p1 is the basic-level spare parts satisfaction rate; T1 is the average time to obtain spare parts at the basic level; P2 is the intermediate-level spare parts satisfaction rate; T2 is the average time to obtain spare parts at the intermediate level; P3 is the base-level spare parts satisfaction rate; T3 is the average time to obtain spare parts at the base level; T4 is the average time to configure spare parts at the base.

[0078] The advantages of this application include: the introduction of average warranty delay time and consideration of spare parts supply satisfaction rate make the calculation and evaluation more accurate.

[0079] This application proposes a method for estimating average failure repair time based on annual early replacement rate (UERR), annual early replacement return rate (URR), and failure rate (FR), which makes the evaluation method more accurate.

[0080] This application can use design parameters and field reliability assessment parameters of similar mass-produced models to assess engine availability, and the assessment method is more accurate.

[0081] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for assessing the availability of an aircraft engine, characterized in that, include: Step S1: Obtain the mean time between maintenance (MTBG) of the aircraft engine. BM and average standby time T SM ; Step S2: Obtain the mean time to repair (MTBL) M and average delay time T DM ; Step S3: Calculate the mean maintenance interval T BM With average standby time T SM The sum of the mean maintenance interval T BM Average standby time T SM Mean time to repair (T) M and average delay time T DM The availability of the engine is represented by the quotient of the engine. Mean time to repair (T) M Including mean time to repair (M) CT and mean preventive maintenance time M PT ; Mean time to repair (M) CT The methods for determining this include: Step S1: Obtain the annual early engine replacement rate (UERR), annual early replacement and return-to-factory rate (URR), and failure rate (FR) for similar aircraft engine models. Step S2: Calculate the percentage of in-situ repair and maintenance frequency for aircraft engines repaired while they are still mounted on the aircraft. Its calculation formula is ; Step S3: Calculate the mean repair time M CT Its calculation formula includes: ； in, The mean repair time for in-situ repairs. For engine detachment, reassembly, and recovery time; Mean time to repair (T) M The calculation formula is as follows: ； In the formula: N C The total number of corrective repairs performed on the engine within a specified time period; M PT Mean time for preventive maintenance; N P The total number of preventative maintenance procedures performed on the engine within a specified time period; Average delay time T DM This includes delays caused by spare parts allocation and acquisition factors at the troop level. The calculation formula is: ； In the formula: s is the probability that the engine can be repaired without the need for spare parts; p1 is the basic-level spare parts satisfaction rate; T1 is the average time to obtain spare parts at the basic level; P2 is the intermediate-level spare parts satisfaction rate; T2 is the average time to obtain spare parts at the intermediate level; P3 is the base-level spare parts satisfaction rate; T3 is the average time to obtain spare parts at the base level; T4 is the average time to configure spare parts at the base.

2. The aero-engine availability assessment method as described in claim 1, characterized in that, Mean time between repairs (MTB) BM The calculation formulas include: Calculate the total number of engine repairs N within the specified time. M Total number of engine repairs N M This includes the number of corrective maintenance operations and the number of preventative maintenance operations. Number of corrective maintenance operations = Engine overhaul interval / Mean time between failures (MTBF); Number of preventive maintenance operations = Engine overhaul interval / Scheduled inspection cycle. The engine mean maintenance interval T is calculated based on the following formula. BM , ； In the formula, T O The engine's operating time within a specified period.

3. The aero-engine availability assessment method as described in claim 1, characterized in that, Calculate the average standby time T SM The methods include: Calculate the daily standby time as ,in , This refers to the engine's average daily operating time. The ratio k of engine operating time to standby time is calculated using the following formula: ; Calculate the average standby time T SM The calculation formula is: .

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