Military aircraft sandstone specific risk assessment method

Abstract

The invention belongs to the technical field of airworthiness, and relates to a military aircraft sandstone specific risk assessment method. The method comprises the following steps: according to the results of aircraft-level functional risk analysis AFHA, system-level functional risk analysis SFHA, aircraft-level fault tree analysis AFTA and preliminary safety assessment PSSA, tracing the functional failure and hazard level of equipment, pipelines and cables with faults caused by sandstone splashing; determining that all affected areas and parts exposed on the surface of the airflow can be affected by splashing of the gravel; according to the affected areas and components and the traceability result, the affected equipment and cables / pipelines in the sandstone splashing area are confirmed, and according to the sandstone splashing safety assessment working principle, airplane functions possibly affected by equipment failure are analyzed; failure influence analysis is carried out on airplane functions possibly influenced by equipment failure, and key functions causing disastrous and dangerous consequences of the airplane are determined; the key functions influencing the flight safety of the airplane are taken as objects, and the reasons causing the function loss are analyzed.

Description

Technical Field

[0001] The invention belongs to the technical field of airworthiness and relates to a method for sand and gravel specific risk assessment of military aircraft. Background Art

[0002] With the rapid development of aviation technology, the requirements for military transport aircraft to adapt to complex environments are becoming increasingly higher. Military transport aircraft have the ability to operate on simple runways and battle-damaged runways. The aircraft body will inevitably be in a gravel damage environment on the runway and apron, causing damage to the body structure. Therefore, it is necessary to fully demonstrate that the body can withstand the impact of gravel and foreign objects to ensure that when a gravel and foreign object impact occurs, the performance of the aircraft will not be reduced, and there will be no unacceptable non-scheduled maintenance grounding.

[0003] When an aircraft takes off and lands, it is a complicated process due to the splashing of sand and gravel on the runway. The potential threat of sand and gravel particles to aircraft is very large, and the destructive impact of sand and gravel impact on aircraft needs to be considered. If sand and dust enter the engine intake duct, it will cause a series of mechanical or electrical failures such as severe wear of various components in the engine intake duct, especially the rotor blades, poor conductivity, etc. The compressor inside the engine may cause engine explosion and body parts breakage after severe wear, causing flight accidents. Summary of the invention

[0004] The invention aims to solve the problem of assessing damage to aircraft structure caused by sand and gravel splashing.

[0005] Technical solution:

[0006] In a first aspect, a method for sand and gravel specific risk assessment for military aircraft is provided, comprising:

[0007] According to the results of aircraft-level functional hazard analysis AFHA, system-level functional hazard analysis SFHA, aircraft-level fault tree analysis AFTA, and preliminary safety assessment PSSA, the functional failure and hazard level of equipment, pipelines and cables that caused failures due to sand and gravel splashing are traced;

[0008] Determine that sand and gravel splashes affect all affected areas and components exposed to the airflow surface;

[0009] According to the affected areas and components and the above traceability results, identify the affected equipment, cables / pipes in the sand and gravel splash area, and analyze the aircraft functions that may be affected by equipment failure based on the sand and gravel splash safety assessment work principles;

[0010] Conduct failure impact analysis on aircraft functions that may be affected by equipment failure, and determine the key functions that may cause catastrophic and dangerous consequences to the aircraft; focus on key functions that affect aircraft flight safety and analyze the causes of function loss.

[0011] Furthermore, the method further comprises:

[0012] Design and install protective measures for systems, components or equipment in affected areas.

[0013] Further, the design principles of protective measures:

[0014] Measures must be taken to deal with catastrophic functional failures caused by sand and gravel splashing; for functional failures assessed to be dangerous, protective measures must be taken as much as possible to avoid their occurrence.

[0015] Furthermore, the working principles for sand and gravel splash safety assessment are:

[0016] Only a single impact is considered, and the combination of failures in the case of multiple impacts is not considered;

[0017] For the parts where the structure is deformed after the impact, it is considered that all the equipment touched by the deformed structure when the sand and gravel splashes fail; for the parts where the structure is penetrated after the impact, the sand and gravel will penetrate the structure and fly backwards, continuing to hit the equipment arranged behind the structure, and it is considered that all the equipment hit by the sand and gravel fragments fail;

[0018] Gas and liquid pipelines, mechanical parts and electrical circuits may break or leak after being hit, and should be considered together with the equipment in the analysis. The judgment principles for their breakage and leakage are the same as those for equipment failure.

[0019] When the installation brackets of equipment, pipelines, mechanical parts, and electrical lines are damaged due to sand and gravel splashing, it is considered that the corresponding equipment installed on the brackets has failed, the pipelines have leaked, the mechanical parts have failed, and the electrical lines have been broken. The judgment principle for bracket damage is the same as the judgment principle for equipment failure.

[0020] It is believed that sand and gravel splashing may occur at any point of the aircraft that can be hit.

[0021] Furthermore, the affected areas and components are one or more of the following:

[0022] a) wing leading edge; b) engine; c) forward fuselage; d) extended landing gear struts; e) cockpit; f) electronics compartment; g) control surfaces.

[0023] Furthermore, AFHA and SFHA give the impact of functional failure on aircraft flight safety, and AFTA and PSSA identify the causes of failures that may lead to functional hazards at the aircraft level and system level, respectively.

[0024] Furthermore, PSSA further locates the cause of the fault to the equipment and pipeline.

[0025] Beneficial Effects

[0026] In order to solve the above technical problems, the present invention provides a method for sand and gravel specific risk assessment of military transport aircraft, determines the damage effect of sand and gravel impact on the aircraft, proposes design improvement measures, provides decisions for aircraft layout and arrangement design, and further improves the safety level of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of sand and gravel specific risk analysis. DETAILED DESCRIPTION

[0028] Gravel splashing aircraft is a sudden and frequent flight accident. Once it occurs, there is a risk of catastrophic accidents. In order to reduce the safety impact of gravel splashing aircraft, it is necessary to identify the catastrophic and dangerous functional failures of the entire aircraft caused by system failures caused by gravel splashing, and provide recommended design protection measures for catastrophic functional failures. Finally, a preliminary assessment result of the safety of gravel splashing at the entire aircraft level is given.

[0029] Combined with Figure 1 , a method for sand and gravel specific risk assessment for military aircraft is provided, comprising the following steps:

[0030] Step 1: Determine the failure mode of sand and gravel splash; trace the functional failure and hazard level of equipment, pipelines and cables caused by sand and gravel splash according to the results of aircraft-level and system-level functional hazard analysis (AFHA, SFHA), aircraft-level fault tree analysis (AFTA), and preliminary safety assessment (PSSA). Among them, AFHA and SFHA give the impact of functional failure on aircraft flight safety, AFTA and PSSA respectively identify the causes of failures that may lead to aircraft-level and system-level functional hazards, and PSSA can further locate the causes of failures to equipment, pipelines, etc. Based on these analysis results, the functional failures and their hazard levels caused by the failure of equipment, pipelines and cables affected by sand and gravel splash can be traced from the bottom up.

[0031] Step 2: Identify the affected areas; sand and gravel splashes will affect all areas and components exposed to the airflow surface. For example:

[0032] a) wing leading edge;

[0033] b) Engine;

[0034] c) forward fuselage;

[0035] d) Landing gear struts extended;

[0036] e) Cockpit;

[0037] f) Electronic equipment compartment;

[0038] g) Control surface.

[0039] Step 3: Identify the affected equipment, cables / pipes in the gravel splash area, and then analyze the aircraft functions that may be affected by equipment failure based on the gravel splash safety assessment work principles. For example, the integrated radio communication navigation identification subsystem gliding antenna installed in the nose area was affected by gravel splash, causing the radio communication navigation system to fail and radio navigation to be unable to be performed; the intelligent probe type atmospheric data computer of the atmospheric data equipment installed in the nose area was affected by gravel splash, resulting in the loss of airspeed data and angle of attack warning during flight.

[0040] The working principles of sand and gravel splash safety assessment are as follows:

[0041] Only a single impact is considered, and the combination of failures in the case of multiple impacts is not considered;

[0042] For the parts where the structure is deformed after the impact, it is considered that all the equipment touched by the deformed structure when the sand and gravel splashed is ineffective. For the parts where the structure is penetrated after the impact, the sand and gravel will penetrate the structure and fly backwards, continuing to hit the equipment arranged behind the structure, and it is considered that all the equipment hit by the sand and gravel fragments is ineffective;

[0043] Gas and liquid pipelines, mechanical parts and electrical circuits may break or leak after being hit, and should be considered together with the equipment in the analysis. The judgment principles for their breakage and leakage are the same as those for equipment failure.

[0044] When the installation brackets of equipment, pipelines, mechanical parts, and electrical lines are damaged due to sand and gravel splashing, it is considered that the corresponding equipment installed on the brackets has failed, the pipelines have leaked, the mechanical parts have failed, and the electrical lines have been broken. The judgment principle for bracket damage is the same as the judgment principle for equipment failure.

[0045] It is believed that sand and gravel splashing the aircraft may occur at any point on the aircraft that can be hit.

[0046] Step 4: Perform failure impact analysis on aircraft functions that may be affected by equipment failure, and determine the key functions that may cause catastrophic and dangerous consequences to the aircraft; analyze the causes of function loss based on key functions that affect aircraft flight safety. Refer to GJB / Z768 to establish a fault tree to determine the failed equipment or combination of failed equipment that causes the function loss. The equipment failure mode can refer to GJB / Z1391 to determine and analyze the causes of function failure.

[0047] For example, the integrated radio communication, navigation and identification subsystem descent antenna installed in the nose area was affected by sand and gravel splashing, causing the radio communication and navigation system to malfunction and making radio navigation impossible, a major failure state. The intelligent probe-type atmospheric data computer of the atmospheric data equipment installed in the nose area was affected by sand and gravel splashing, causing the loss of airspeed data during flight and the loss of angle of attack warning, a dangerous failure state.

[0048] Step 5: Determine the system or equipment design and installation protection measures for the affected areas.

[0049] Measures must be taken to deal with catastrophic functional failures caused by sand and gravel splashing; for functional failures assessed to be dangerous, protective measures must be taken as much as possible to avoid their occurrence.

Claims

1. A method for specific risk assessment of sand and gravel for military aircraft, characterized in that: include: According to the results of aircraft-level functional hazard analysis AFHA, system-level functional hazard analysis SFHA, aircraft-level fault tree analysis AFTA, and preliminary safety assessment PSSA, the functional failure and hazard level of equipment, pipelines and cables that caused failures due to sand and gravel splashing are traced; Determine that sand and gravel splashes affect all affected areas and components exposed to the airflow surface; According to the affected areas and components and the above traceability results, identify the affected equipment, cables / pipes in the sand and gravel splash area, and analyze the aircraft functions that may be affected by equipment failure based on the sand and gravel splash safety assessment work principles; Conduct failure impact analysis on aircraft functions that may be affected by equipment failure, and determine the key functions that may cause catastrophic and dangerous consequences to the aircraft; focus on key functions that affect aircraft flight safety and analyze the causes of function loss.

2. The method according to claim 1, characterized in that The method further comprises: Design and install protective measures for systems, components or equipment in affected areas.

3. The method according to claim 1, characterized in that Design principles for protective measures: Measures must be taken to deal with catastrophic functional failures caused by sand and gravel splashing; for functional failures assessed to be dangerous, protective measures must be taken as much as possible to avoid their occurrence.

4. The method according to claim 1, characterized in that: The working principles for sand and gravel splash safety assessment are: Only a single impact is considered, and the combination of failures in the case of multiple impacts is not considered; For the parts where the structure is deformed after the impact, it is considered that all the equipment touched by the deformed structure when the sand and gravel splashes fail; for the parts where the structure is penetrated after the impact, the sand and gravel will penetrate the structure and fly backwards, continuing to hit the equipment arranged behind the structure, and it is considered that all the equipment hit by the sand and gravel fragments fail; Gas and liquid pipelines, mechanical parts and electrical circuits may break or leak after being hit, and should be considered together with the equipment in the analysis. The judgment principles for their breakage and leakage are the same as those for equipment failure. When the installation brackets of equipment, pipelines, mechanical parts, and electrical lines are damaged due to sand and gravel splashing, it is considered that the corresponding equipment installed on the brackets has failed, the pipelines have leaked, the mechanical parts have failed, and the electrical lines have been broken. The judgment principle for bracket damage is the same as the judgment principle for equipment failure. It is believed that sand and gravel splashing the aircraft may occur at any point on the aircraft that can be hit.

5. The method according to claim 1, characterized in that The affected areas and components are one or more of the following: a) wing leading edge; b) engine; c) forward fuselage; d) extended landing gear struts; e) cockpit; f) electronics compartment; g) control surfaces.

6. The method according to claim 1, characterized in that AFHA and SFHA give the impact of functional failure on aircraft flight safety, and AFTA and PSSA identify the causes of failures that may lead to aircraft-level and system-level functional hazards, respectively.

7. The method according to claim 1, characterized in that PSSA further locates the cause of the fault to the equipment and pipeline.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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