Civil helicopter main minimum equipment list determination method

Abstract

The invention provides a method for determining a main minimum equipment list of a civil helicopter, and the method improves the analysis process of a main minimum equipment list determination technology based on a safety analysis technology, and reorganizes an MMEL logic decision analysis process, a restoration deadline qualitative and quantitative determination method, and a PMMEL verification principle and verification process. According to the method, an MMEL list is obtained through comprehensive evaluation of information such as a use scene of a project, a unit operation condition, influence of failure on the unit and work of ground crew, influence of failure on other system equipment, post-failure disposal, a verification condition of the project, an actual operation condition, regulation conformity and the like; the method breaks through the defects that the previous helicopter model master minimum equipment list / minimum flying list item is not strictly determined and is not fully tested and verified.

Description

Technical Field

[0001] The present application belongs to the technical field of safety design analysis, and in particular, relates to a method for determining a master minimum equipment list of a civil helicopter. Background Art

[0002] The MMEL should be prepared based on the MMEL applicable to the aircraft type. Therefore, civil helicopters need to compile a MMEL to confirm that the aircraft has sufficient capabilities to maintain the required safety level when it is dispatched with inoperative items and when secondary failures occur during flight. The MMEL contains the conditions, limitations and procedures for aircraft operation when these equipment are inoperative.

[0003] At present, the technical analysis process for determining the MMEL takes the safety impact of equipment failure and the safety impact caused by secondary failure as the basis for whether to include PMMEL items. However, it does not consider factors such as whether the failure can be discovered by the flight crew, route ground staff or alarms, as well as the potential impact on operation and maintenance.

[0004] In addition, the definition of secondary failures, the qualitative and quantitative determination methods of the repair period, the PMMEL verification principles and the verification process are not clear enough, resulting in the lack of rigor in the determination of the minimum equipment list / minimum release list items in actual work, making it difficult to obtain the approval of the authority. Therefore, it is urgent to improve the original analysis process and break through the previous defects. Summary of the invention

[0005] Purpose of the invention: In the above engineering context, this application improves the technical analysis process for determining the master minimum equipment list based on safety analysis technology, and reorganizes the MMEL logical decision analysis process, the repair period limitation and quantitative determination method, and the PMMEL verification principles and verification process.

[0006] The present application provides a method for determining a master minimum equipment list of a civil helicopter, the method comprising the following steps:

[0007] If a PMMEL candidate item fails, it can be discovered by the flight crew, route ground staff or alarm;

[0008] If the fault impact is not "NSE", analyze the fault impact;

[0009] If the impact of the fault exceeds "MIN", the impact of the fault can be mitigated to "MIN" or below through restrictions, operating procedures (O) and / or maintenance procedures (M), establish restrictions, operating procedures (O) and / or maintenance procedures (M) to mitigate the impact of the fault, and analyze the impact of the secondary fault;

[0010] If the fault impact does not exceed "MIN", analyze the impact of subsequent faults;

[0011] If the impact of secondary failures cannot maintain the safety level, the impact of secondary failures can be mitigated to "MIN" or below through restrictions, operating procedures (O) and / or maintenance procedures (M). Establish restrictions, operating procedures (O) and / or maintenance procedures (M) to mitigate the impact of secondary failures, and conduct potential operation and maintenance impact analysis;

[0012] If the secondary failure effect cannot maintain the safety level, the secondary failure effect cannot be mitigated to "MIN" and below by limitation, operating procedures (O) and / or maintenance procedures (M);

[0013] Conduct qualitative or quantitative safety analysis based on the SSA report; if the airworthiness safety requirements are met, conduct potential operation and maintenance impact analysis;

[0014] If the impact of the secondary failure can maintain a safety level, conduct potential operation and maintenance impact analysis.

[0015] Preferably, if a PMMEL candidate item fails, before it can be discovered by the flight crew, route ground staff or alarm, it also includes:

[0016] Identify PMMEL candidate projects.

[0017] Preferably, the method further comprises:

[0018] If the fault impact is "NSE", perform potential operation and maintenance impact analysis.

[0019] Preferably, the potential operation and maintenance impact analysis process includes:

[0020] The potential operational and maintenance impacts are acceptable;

[0021] List the appropriate PMMEL candidate items into the PMMEL items to obtain the civil helicopter master minimum equipment list.

[0022] Preferably, the potential operation and maintenance impact analysis process further includes:

[0023] The potential operation and maintenance impacts are unacceptable and can be reduced through restrictions, operating procedures (O) and / or maintenance procedures (M);

[0024] Establish limitations, operating procedures (O) and / or maintenance procedures (M) to reduce potential operational and maintenance impacts;

[0025] List the appropriate PMMEL candidate items into the PMMEL items to obtain the civil helicopter master minimum equipment list.

[0026] Preferably, the operation and maintenance impact refers to the workload of the flight crew and the complexity of maintenance.

[0027] Preferably, the qualitative or quantitative safety analysis is carried out according to the SSA report, including:

[0028] According to the SSA report, safety verification methods are selected for different levels of functional failure states to carry out qualitative or quantitative safety analysis.

[0029] Preferably, restrictions are established, including:

[0030] Establish criteria for determining the repair period and determine the repair period.

[0031] Preferably, the secondary failure impact takes into account redundant items of inoperative items, items that provide the same function / same information, items that provide monitoring functions, and operations performed after a failure of an independent item. PMMEL items are required, and qualitative or quantitative analysis is performed based on the system safety analysis results to identify their impact on the safety of helicopter operations.

[0032] Preferably, the step of listing suitable PMMEL candidate items into PMMEL items to obtain a civil helicopter master minimum equipment list comprises:

[0033] Verify PMMEL projects;

[0034] If the PMMEL item meets the requirements, the PMMEL item will be included in the Master Minimum Equipment List of civil helicopters.

[0035] Beneficial technical effects of this application:

[0036] This method improves the technical analysis process for determining the master minimum equipment list based on safety analysis technology, and reorganizes the MMEL logical decision analysis process, the qualitative and quantitative determination method of the repair period, and the PMMEL verification principles and verification process.

[0037] This method obtains the MMEL list through comprehensive evaluation of the project's usage scenario, crew operation, the impact of failure on the crew and ground crew work, the impact of failure on other system equipment, post-failure disposal, project verification, actual operation, regulatory compliance and other information. It breaks through the defects of the previous helicopter model master minimum equipment list / minimum flight list items that were not rigorously determined and not fully tested and verified. It has been unanimously recognized by the authority. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of a method for determining a master minimum equipment list of a civil helicopter provided in an embodiment of the present application;

[0039] Figure 2It is a flow chart of a method for verifying the master minimum equipment list of a civil helicopter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] See also Figure 1-Figure 2 The present application provides a method for determining a master minimum equipment list for a civil helicopter, comprising the following steps:

[0041] (I) The recommended item determination procedure for the Master Minimum Equipment List (MMEL) is attached. Figure 1 , the specific process is as follows:

[0042] Step 1: Can the fault be discovered by the flight crew, line ground staff or alarms?

[0043] This step is to confirm the fault of the project and analyze whether it can be found through the following means. If not, it cannot be included in the Proposed Master Minimum Equipment List (PMMEL) project; if it can, proceed to step 2 analysis:

[0044] a) Warning: Faults displayed on the flight display system, warning system, equipment self-test, etc.

[0045] b) Faults that can be discovered by the flight crew:

[0046] i. Tactile sensation: such as abnormal control force of the joystick system, abnormal vibration on the aircraft, etc.;

[0047] ii. Sound: such as unusual sounds, abnormal noises, etc.;

[0048] iii. Visual inspection: such as screen flickering, button damage, etc.

[0049] c) Faults that can be discovered by airline ground staff:

[0050] d) Faults discovered by ground crew during pre-flight and post-flight inspections.

[0051] Step 2: Is it No Safety Effect (NSE)?

[0052] According to the system safety assessment results, confirm whether the failure impact of the non-working project is "NSE". If so, go to step 8; if not, analyze the failure impact.

[0053] Step 3: Is the impact of the fault more than minor (MIN)?

[0054] The failure impact should describe the impact of the inoperative item on helicopter flight, system operation or crew workload in various operating scenarios (day and night, instrument flight rules / visual flight rules, etc.). The analysis should also consider redundant items, items providing the same function / same information, associated MMEL items, regulatory requirements, etc., to evaluate the possible safety consequences on helicopter operations in various operating environments.

[0055] Determine whether the impact on the safety of the helicopter when the project is not working will exceed the "MIN". If it does not exceed the "MIN" (including the "MIN"), analyze the impact of secondary failures; if it exceeds the "MIN", go to step 4.

[0056] Step 4: Can the impact of the fault be mitigated to "MIN" or below by limiting and operating procedures (O) and / or maintenance procedures (M)?

[0057] Determine whether the impact of the failure can be mitigated to "MIN" or below by taking restrictive measures or adjusting the (O) procedure / (M) procedure. If not, it cannot be included in the PMMEL project. If so, ensure the safety requirements of the helicopter by formulating corresponding restrictions, establishing (O) procedures, (M) procedures and other safety measures, and then analyze the impact of subsequent failures.

[0058] The corresponding restrictions include establishing repair period types, adding operating restrictions, etc.

[0059] Relevant measures include transferring functions to normal parts, using alternative functions, adjusting operating restrictions, adjusting operating procedures, adjusting maintenance procedures, etc.

[0060] Step 5. Can the level of security be maintained?

[0061] When analyzing the impact of subsequent failures, consider the impact of the next associated critical failure that may occur on aircraft flight or system operation in the case of a non-working item, and evaluate the possible safety consequences of the above combined failures on the actual operation of the helicopter, crew execution procedures, and crew workload under various operating environments.

[0062] Secondary failures generally take into account redundant items of inoperative items, items that provide the same functions / same information, items that provide monitoring functions, and operations performed after a failure of an independent item that require the use of PMMEL items. Based on the results of the system safety analysis, a qualitative or quantitative analysis is performed to identify their impact on the safety of helicopter operations.

[0063] If the consequences are "MIN" or below, go to step 8. If the safety impact of the failure exceeds "MIN", go to step 6 for analysis.

[0064] Step 6. Can the fault impact be mitigated to “MIN” or below by limiting, (O) and / or (M) items?

[0065] Determine whether the unit can still mitigate the impact of the fault to "MIN" or below by taking restrictive measures and adjusting (O) procedures / (M) procedures. If yes, then formulate corresponding restrictions, establish (O) procedures, (M) procedures and other safety measures, and then go to step 8. If not, conduct quantitative or qualitative safety analysis based on the SSA report.

[0066] Step 7. Does it meet airworthiness safety requirements?

[0067] According to the SSA report, select safety verification methods for different functional failure status levels to carry out qualitative or quantitative safety analysis to confirm whether the functional failure status meets the airworthiness requirements. If the safety requirements for failure consequences and probabilities of airworthiness certification are met, go to step 8; if the safety requirements are not met, it cannot be included in the PMMEL project.

[0068] Step 8. Are potential operational and maintenance impacts acceptable?

[0069] The main analysis here is the impact of inoperative items on flight crew workload, maintenance complexity, etc.

[0070] If the requirements for flight crew workload, maintenance complexity, etc. are acceptable, then include them in the MMEL recommended items; if not, go to step 9.

[0071] Step 9. Can the operation and maintenance impacts be reduced through restrictions and (O) and / or (M)?

[0072] If measures can be taken to mitigate the impact, the helicopter's safety level can be ensured by formulating appropriate restrictions, establishing (O) procedures, (M) procedures and other safety measures, and it can be allowed to be included in the PMMEL project. If measures cannot be taken to mitigate the impact, it will not be allowed to be included in the PMMEL project.

[0073] (II) PMMEL verification principles and verification flow chart are attached Figure 2 , the verification content includes:

[0074] a) Fault impact analysis;

[0075] b) Correctness of operation / maintenance procedures;

[0076] c) Flight crew workload.

[0077] Verification methods include theoretical analysis and operational verification.

[0078] The theoretical analysis mainly identifies the MMEL recommended items through the process in (I), and the impact of their failure on helicopter flight safety, crew workload and the M / O procedures that need to be taken, and then submits them to the Flight Operations Evaluation Board (FOEB) for review and confirmation of whether they are reasonable and feasible.

[0079] Operational verification includes ground verification and flight verification. Ground verification is when ground crew and flight crew operate the (M) and (O) procedures after a failure of an MMEL recommended item on the ground to verify whether they are reasonable and feasible; flight verification is when flight crew operate the (O) procedures after a failure of an MMEL recommended item in the air to verify whether they are reasonable and feasible and the impact of the failure and the crew workload.

[0080] The verification conditions are:

[0081] The applicant should carry out verification based on the usage scenario of the PMMEL project, the purpose of verification, the usage scenario restrictions of the MMEL project and the safety analysis to select appropriate verification conditions (day and night, IFR / VFR, single-pilot / dual-pilot, various weather conditions, etc.) to ensure that the impact of the PMMEL project being out of operation is fully verified.

[0082] For flight verification, when selecting the test profile, the applicant should formulate the flight verification profile and flight conditions according to the verification needs of the verification project, and carry out the flight verification work of the MMEL recommended projects.

[0083] For ground verification, the applicant can organize the verification work according to the verification needs of the verification project.

[0084] (III) It should be noted that:

[0085] a) When determining PMMEL items, cockpit effects, flight crew, line ground staff or warning findings, as well as potential operational and maintenance impacts (flight crew workload, maintenance complexity, etc.) were considered, and the MMEL logical decision analysis process was reorganized;

[0086] b) Improved the criteria for determining the repair period and supplemented the qualitative and quantitative determination methods of the repair period as follows:

[0087] For equipment without safety impact, if the equipment failure will not affect the crew workload, there are no flight restrictions, and the pilot training, subsequent habits and procedures do not rely on the use of the equipment, then the D-type repair period is recommended. Usually applicable to optional equipment or equipment installed beyond regulatory requirements.

[0088] For equipment or components whose safety impact on the project itself reaches MIN or above, the repair period should be at least Class C. The specific judgment criteria are as follows:

[0089] For equipment or components whose safety impact is MIN, considering the impact of secondary failures, if the impact of equipment non-operation on operation and crew workload is small, only simple restrictions, M / O procedures or no restrictions are required, and the flight crew workload is slightly increased (for example, the non-operation of the item only affects the efficiency or comfort of the crew / helicopter work, only requires the pilot to perform relatively simple procedures, or has a small impact on the pilot's operation (such as shutting down certain equipment)), then a Class C repair period is recommended.

[0090] For equipment or components whose safety impact reaches serious (Major, MAJ) or above, considering the impact of secondary failures, the non-operation of the equipment has a great impact on safety and helicopter operation. It may be necessary to reduce the impact of the failure to MIN or below through greater restrictions (for example, realizing its function through effective alternative methods or procedures) and relatively complex M / 0 procedures, but it will have a greater impact on the crew's workload (for example, the pilot needs to perform more complex operations after the item is not working, or it has a greater impact on the pilot's operation). In this case, a Class B repair period is recommended.

[0091] For equipment or parts whose secondary failure impact reaches hazardous (HAZ) or above, if the failure impact cannot be mitigated to MIN through necessary restrictions and M / O procedures, it is necessary to perform quantitative calculations to give the maximum repair period, within which the airworthiness safety requirements can be met, or if the equipment must be installed in the helicopter according to the operating regulations and is allowed to be released under certain restrictions (such as maneuvering flight), a Class A repair period is recommended.

[0092] The calculation method for the Class A repair period is as follows:

[0093] The maximum repair period for MMEL recommended items that may lead to catastrophic failure is:

[0094] T MAX [PH]=1*10 -9 / (PF*PR)

[0095] For MMEL recommended items that may lead to dangerous failure conditions, the maximum repair period is:

[0096] T MAX [FH]=1*10 -7 / (PF*FR)

[0097] Where: T MAX [FH] is the maximum repair period (flight hours);

[0098] PF is the probability per flight hour of failure status in dispatch status;

[0099] FR is the failure rate per flight hour of the MMEL recommended item.

[0100] c) Added listing requirements:

[0101] Add relevant content of placards: When each MMEL item fails (does not work), the equipment that does not work, is prohibited or restricted from use should be warned with obvious signs, but these signs should not affect the normal operation of the flight crew to inform or remind the flight crew and maintenance personnel of their technical conditions.

[0102] When each MMEL item fails (is not working), the inoperative, prohibited or restricted equipment should be clearly marked with warning signs to inform or alert the flight crew and maintenance personnel of its technical condition.

[0103] Note: Placards should be placed as close to the relevant control or indicator positions as practically possible near the inoperative components or parts, but these signs and placards should not affect the normal operation of the flight crew. Unless otherwise specified, the wording and installation location of the placards can usually be determined by the operator.

[0104] d) Clarify the definition of secondary failures;

[0105] e) The PMMEL verification principles and verification process were reorganized.

Claims

1. A method for determining a master minimum equipment list for a civil helicopter, characterized in that: The method comprises the following steps: If a PMMEL candidate item fails, it can be discovered by the flight crew, route ground staff or alarm; If the fault impact is not "NSE", analyze the fault impact; If the impact of the fault exceeds "MIN", the impact of the fault can be mitigated to "MIN" and below through restrictions, operating procedures (O) and / or maintenance procedures (M), establish restrictions, operating procedures (O) and / or maintenance procedures (M) to mitigate the impact of the fault, and analyze the impact of the secondary fault; If the fault impact does not exceed "MIN", analyze the impact of subsequent faults; If the impact of secondary failures cannot maintain the safety level, the impact of secondary failures can be mitigated to "MIN" or below through restrictions, operating procedures (O) and / or maintenance procedures (M). Establish restrictions, operating procedures (O) and / or maintenance procedures (M) to mitigate the impact of secondary failures, and conduct potential operation and maintenance impact analysis; If the consequential failure effects cannot maintain the safety level, the consequential failure effects cannot be mitigated to "MIN" and below by limitations, operating procedures (O) and / or maintenance procedures (M); Conduct qualitative or quantitative safety analysis based on the SSA report; if the airworthiness safety requirements are met, conduct potential operation and maintenance impact analysis; If the impact of the secondary failure can maintain a safety level, conduct potential operation and maintenance impact analysis.

2. The method according to claim 1, characterized in that If a PMMEL candidate item fails, before it can be discovered by the flight crew, route ground staff or alarm, it also includes: Identify PMMEL candidate projects.

3. The method according to claim 2, characterized in that The method further comprises: If the fault impact is "NSE", perform potential operation and maintenance impact analysis.

4. The method according to claim 3, characterized in that The potential operation and maintenance impact analysis process is as follows: The potential operational and maintenance impacts are acceptable; List the appropriate PMMEL candidate items into the PMMEL items to obtain the civil helicopter master minimum equipment list.

5. The method according to claim 4, characterized in that The potential operation and maintenance impact analysis process also includes: The potential operation and maintenance impacts are unacceptable and can be reduced through restrictions, operating procedures (O) and / or maintenance procedures (M); Establish limitations, operating procedures (O) and / or maintenance procedures (M) to reduce potential operational and maintenance impacts; List the appropriate PMMEL candidate items into the PMMEL items to obtain the civil helicopter master minimum equipment list.

6. The method according to claim 3, characterized in that The operational and maintenance impacts refer to the workload of the flight crew and the complexity of maintenance.

7. The method according to claim 1, characterized in that According to the SSA report, conduct qualitative or quantitative safety analysis, including: According to the SSA report, safety verification methods are selected for different levels of functional failure states to carry out qualitative or quantitative safety analysis.

8. The method according to claim 1, characterized in that: Establish restrictions, including: Establish criteria for determining the repair period and determine the repair period.

9. The method according to claim 1, characterized in that: The secondary failure impact takes into account redundant items of inoperative items, items that provide the same functions / same information, items that provide monitoring functions, and operations performed after a failure of an independent item. PMMEL items are required to conduct qualitative or quantitative analysis based on the system safety analysis results to identify their impact on the safety of helicopter operations.

10. The method according to claim 5, characterized in that The above mentioned PMMEL candidate items are listed in the PMMEL items to obtain the civil helicopter master minimum equipment list, including: Verify PMMEL projects; If the PMMEL item meets the requirements, the PMMEL item will be included in the Master Minimum Equipment List of civil helicopters.

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