A method for verifying the smoke evacuation of a cockpit of a through-duct amphibious aircraft

Abstract

The application discloses a kind of cabin configuration amphibious aircraft cockpit smoke evacuation airworthiness verification method.The method comprises: executing cockpit smoke evacuation ground test, and executing seat cabin pressure regulating system emergency pressure relief function special flight test, and emergency drill is carried out by flight crew;Determine equivalent severe verification condition;Build hierarchical smoke evacuation program;Under equivalent severe verification condition, execute flight test, release smoke to cockpit, when smoke concentration reaches test requirement, record smoke evacuation starting time, execute hierarchical smoke evacuation program by flight crew, record smoke evacuation ending time;Based on the smoke evacuation time under degradation condition is not more than airworthiness time limit, and the ventilation volume and smoke evacuation time inverse relationship verification verified in ground test, determine that the smoke evacuation time under normal condition also meets the requirement, draw the conclusion that cockpit smoke evacuation capability meets the airworthiness requirement.The application can realize efficient and safe verification to cabin configuration amphibious aircraft cockpit smoke evacuation airworthiness.

Description

Technical Field

[0001] This invention relates to the field of aircraft airworthiness verification and flight testing technology, and in particular to a method for airworthiness verification of smoke exhaust from the cockpit of an amphibious aircraft with a through-cabin configuration. Background Technology

[0002] With the continued growth of global air transport demand and the continuous expansion of waterborne operations, amphibious aircraft, as special aircraft capable of taking off and landing on both land and water, have irreplaceable strategic value in fields such as marine monitoring, emergency rescue, and forest fire fighting. The cockpit smoke extraction capability is a key airworthiness indicator to ensure flight safety.

[0003] Currently, traditional cockpit smoke exhaust airworthiness verification methods generally rely on conducting flight tests directly under normal air conditioning system operation, releasing smoke and observing the smoke exhaust time to determine whether airworthiness requirements are met. However, traditional cockpit smoke exhaust airworthiness verification methods are not adaptable to aircraft configurations. The through-cabin configuration significantly increases the effective ventilation volume of the cockpit, making it difficult for conventional smoke generation to accumulate to the required concentration in a local area of ​​the cockpit for testing. At the same time, the special characteristics of aircraft without autopilot are not fully considered. Flight crews must simultaneously perform aircraft control and smoke exhaust operations under limited visibility conditions, resulting in a high concentration of safety risks. The lack of a progressive verification system from ground testing to flight testing leads to a concentrated release of flight test risks and unclear test safety boundaries. Summary of the Invention

[0004] This invention provides a method for verifying the airworthiness of smoke exhaust in the cockpit of an amphibious aircraft with a through-cabin configuration, so as to achieve efficient and safe verification of the airworthiness of smoke exhaust in the cockpit of an amphibious aircraft with a through-cabin configuration, and overcome the problems of smoke accumulation in the through-cabin configuration, high safety risks in testing without autopilot, and lack of a progressive verification system.

[0005] According to one aspect of the present invention, a method for airworthiness verification of smoke exhaust in the cockpit of an amphibious aircraft with a through-cabin configuration is provided, the method comprising: Conduct ground tests of cockpit smoke exhaust. With the aircraft ground-based and stopped, verify the smoke exhaust function under normal operating conditions of both air conditioning system dual cooling components and single cooling component, obtain smoke exhaust time data under both conditions, verify the inverse relationship between ventilation volume and smoke exhaust time, conduct special flight tests of emergency depressurization function of cabin pressure regulation system, independently verify the safety of emergency depressurization, and organize flight crews to conduct emergency drills. When the cockpit smoke concentration cannot meet the test requirements due to the open-cabin configuration while the aircraft is in normal air conditioning system operation mode, the air conditioning system degraded operation mode is selected as the equivalent severe verification condition. The degraded operation mode reduces the cockpit ventilation to less than 50% of the normal ventilation by shutting down a cooling component or reducing the amount of engine bleed air. A graded smoke extraction procedure is established, which includes a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure uses the air conditioning system to ventilate and extract smoke during normal operation. The emergency smoke extraction procedure uses the pressure difference between the inside and outside of the cabin to quickly extract smoke by pressing the emergency depressurization switch. The decision-making authority for switching the graded smoke extraction procedure is given to the flight crew. Flight tests were conducted under the equivalent severe verification conditions. Smoke was released into the cockpit. When the smoke concentration reached the test requirements, the start time of smoke exhaust was recorded. The flight crew then executed the graded smoke exhaust procedure and recorded the end time of smoke exhaust. Based on the fact that the smoke exhaust time under the degraded operating mode does not exceed the airworthiness time limit, and the verification of the inverse relationship between ventilation volume and smoke exhaust time through ground tests, it is determined that the smoke exhaust time under normal operating conditions also meets the requirements, and the conclusion is drawn that the cockpit smoke exhaust capacity meets the airworthiness requirements.

[0006] The technical solution of this invention, through ground-based cockpit smoke extraction tests, verifies the smoke extraction function under both normal operating conditions of the air conditioning system with dual cooling components and normal operating conditions of a single cooling component while the aircraft is ground-based and stationary. Smoke extraction time data is obtained under both conditions to verify the inverse relationship between ventilation volume and smoke extraction time. A dedicated flight test of the emergency depressurization function of the cabin pressure regulation system is also conducted to independently verify the safety of emergency depressurization. Emergency drills are organized for the flight crew, thus establishing a safety baseline for flight testing. Pilots can gain an initial understanding of smoke concentration and the air conditioning system's smoke extraction capability, enhancing the crew's confidence in the smoke extraction test. When the cockpit smoke concentration cannot meet the test requirements due to the open-cabin configuration while the aircraft is in normal air conditioning system operating mode, a degraded air conditioning system operating mode is selected as an equivalent severe verification condition. This degraded operating mode reduces the cockpit ventilation volume to less than 50% of the normal ventilation volume by shutting down one cooling component or reducing the amount of engine bleed air. This avoids the need for an ultra-large capacity smoke generator to achieve the test concentration in the large open-cabin space, allowing the test to be completed using the aircraft's own air conditioning regulation capabilities. A tiered smoke extraction procedure is constructed, comprising a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure utilizes the normal operation of the air conditioning system for ventilation and smoke extraction. The emergency smoke extraction procedure utilizes the pressure difference between the inside and outside of the cabin to rapidly extract smoke by pressing an emergency depressurization switch. The decision-making authority for switching between the tiered smoke extraction procedures is granted to the flight crew, preventing the fixed procedure from failing under extreme conditions. Flight tests are conducted under the equivalent severe verification conditions, releasing smoke into the cockpit. When the smoke concentration reaches the test requirements, the start time of smoke extraction is recorded. The flight crew then executes the tiered smoke extraction procedure, recording the end time of smoke extraction. This improves test efficiency and safety. Based on the fact that the smoke extraction time in the degraded operating mode does not exceed the airworthiness time limit, and the inverse relationship between ventilation volume and smoke extraction time verified by ground tests, it is determined that the smoke extraction time under normal operating conditions also meets the requirements. Therefore, the conclusion that the cockpit smoke extraction capability meets airworthiness requirements is drawn, ensuring the reliability of the conclusion and providing a solid basis for airworthiness certification. This invention establishes a safety baseline through progressive testing. When it is determined that the smoke concentration of the air conditioning system cannot meet the test requirements under normal operating conditions due to the through-cabin configuration, a degraded operating mode is selected as an equivalent severe verification condition. A graded smoke exhaust procedure including normal smoke exhaust and emergency smoke exhaust is constructed and the crew is given autonomous decision-making power. Flight tests are performed under the degraded operating mode. Based on the smoke exhaust time meeting the requirements under the degraded operating mode, it is determined that the normal operating conditions also meet the requirements, and an airworthiness compliance conclusion is drawn. This achieves efficient and safe verification of the airworthiness of smoke exhaust in the cockpit of an amphibious aircraft with a through-cabin configuration, overcoming the problems of smoke accumulation difficulties under through-cabin configuration, high safety risks in testing without autopilot, and lack of a progressive verification system.

[0007] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a flowchart of a method for verifying the airworthiness of a through-cabin configuration amphibious aircraft cockpit smoke exhaust, according to Embodiment 1 of the present invention. Detailed Implementation

[0010] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0011] It should be noted that the terms "first," "second," "target," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0012] Example 1 Figure 1 This is a flowchart illustrating a method for verifying the airworthiness of a through-cabin configuration amphibious aircraft's cockpit smoke exhaust, as provided in Embodiment 1 of the present invention. This embodiment is applicable to situations involving the verification of cockpit smoke exhaust airworthiness for through-cabin configuration amphibious aircraft. Figure 1 As shown, the method includes: S110. Conduct a ground test of the cockpit smoke exhaust system. With the aircraft ground-based and stopped, verify the smoke exhaust function under normal operating conditions of both air conditioning system dual-cooling components and single-cooling component. Obtain smoke exhaust time data under both conditions, verify the inverse relationship between ventilation volume and smoke exhaust time, and conduct a special flight test of the emergency depressurization function of the cabin pressure regulation system to independently verify the safety of emergency depressurization. Organize the flight crew to conduct emergency drills.

[0013] In this context, "refrigeration component" refers to the refrigeration unit within the air conditioning system, typically operating independently. "Smoke extraction time" refers to the time elapsed during ground or flight testing, from the moment the smoke concentration reaches the required level (smoke emission ceases) until the smoke is completely dissipated (no longer affecting flight crew operations). For example, in ground testing, this might be 57 seconds for a dual-component configuration and 127 seconds for a single-component configuration. "Ventilation volume" refers to the flow rate of fresh air supplied to the cockpit by the air conditioning system. "Smoke extraction time" refers to the time interval from the start to the end of smoke extraction.

[0014] Specifically, this step involves progressive pre-test preparation and risk release. Before the flight test, the following preparations are completed in sequence: Conduct a ground-based cockpit smoke extraction test: With the aircraft stationary on the ground, perform ground-based smoke extraction verification under two normal operating conditions: normal operation of both air conditioning system cooling components and normal operation of a single cooling component. This verifies the smoke extraction function, obtains smoke extraction time data under both conditions, and verifies the inverse relationship between ventilation volume and smoke extraction time. The core purpose of the ground test is twofold: firstly, to verify the usability of the air conditioning system's smoke extraction function; secondly, under ground conditions, the external environment is at ground atmospheric pressure, and the pressure difference between the inside and outside of the cockpit is lower than during high-altitude cruise, resulting in a smaller pressure difference on both sides of the exhaust valve, weaker smoke extraction driving force, and lower air exchange rate. Therefore, ground-based smoke extraction conditions are more severe than flight-based smoke extraction conditions. If the smoke extraction time meets the requirements during the ground test, emergency depressurization can be used during flight to quickly expel smoke using the pressure difference, resulting in superior smoke extraction performance. The successful completion of ground tests establishes a safety baseline for flight tests, allowing pilots to gain an initial understanding of smoke concentration and the air conditioning system's smoke extraction capabilities, thus enhancing the crew's confidence in smoke extraction tests. Flight verification of the emergency depressurization function of the cabin pressure regulation system was conducted: prior to the smoke extraction flight test, a dedicated flight test independently verified the emergency depressurization function of the cabin pressure regulation system. Dedicated verification confirmed that after pressing the emergency depressurization switch, the exhaust valve opened according to the predetermined logic; the cabin altitude change rate and peak cabin altitude were within the aircraft certification limits; and the emergency depressurization operation did not affect normal aircraft handling. By decoupling the emergency depressurization function verification from the comprehensive smoke extraction test in stages, the simultaneous introduction of two unknown factors—"whether the smoke extraction effect meets the standards" and "whether the emergency depressurization function is normal"—into the smoke extraction test, reducing the cumulative effect of test risks. Emergency Drills for Flight Crews: Before flight testing, multiple emergency drills are conducted for the flight crew. These drills cover at least: safety precautions, the commands and actions for executing graded smoke extraction procedures, the proper use of non-verbal optical signals, the coordination between flight controls and smoke extraction operations during the smoke extraction process, and procedures for aborting and exiting the test in abnormal situations. Through these emergency drills, the crew can become fully familiar with the smoke extraction test procedures before entering actual flight testing, reducing the uncertainty of the test caused by human factors.

[0015] It should be noted that the inverse relationship between ventilation volume and smoke extraction time means that, under the same smoke generation conditions, the greater the air supply flow (ventilation volume) of the air conditioning system, the greater the airflow through the cockpit per unit time, the faster the smoke is extracted, and the shorter the smoke extraction time; conversely, the smaller the ventilation volume, the longer the smoke extraction time. This relationship was verified by ground test data of dual / single components (57 seconds vs. 127 seconds).

[0016] For example, the aircraft is an amphibious aircraft without autopilot, and there is no airtight partition between the cockpit and the rear passageway. The air supply airflow of the air conditioning system flows from the front to the rear of the cockpit.

[0017] For example, the severity of ground tests is determined by the following criteria: the external environmental pressure in ground conditions is atmospheric pressure, and the pressure difference between the inside and outside of the cabin is lower than that in high-altitude cruise conditions, resulting in lower smoke exhaust driving force and air exchange rate than in flight conditions. Therefore, the smoke exhaust time in ground tests constitutes a conservative upper limit for the smoke exhaust time in flight tests.

[0018] For example, ground tests were conducted under normal operating conditions of dual refrigeration components and normal operating conditions of single refrigeration components. By comparing the measured smoke exhaust time under the two conditions, the inverse relationship between air conditioning air supply flow and smoke exhaust time was verified, providing quantitative support for the equivalent severity judgment logic. Among them, the ventilation volume of the single component condition is about 50% of that of the dual component condition, and its smoke exhaust time constitutes a conservative upper limit for the smoke exhaust time of the dual component condition.

[0019] For example, the emergency depressurization function-specific flight test is conducted independently before the smoke exhaust flight test, and at least confirms that: after pressing the emergency depressurization switch, the exhaust valve opens according to the predetermined logic, the cabin altitude change rate and the peak cabin altitude are within the aircraft certification limits, and the emergency depressurization operation does not affect the normal operation of the aircraft.

[0020] For example, emergency drills should at least cover: safety protection, training on the execution commands and actions of graded smoke extraction procedures, training on the standard use of non-verbal optical signals, training on the coordination of flight control and smoke extraction operations under conditions of limited visibility, and training on abort and exit procedures in abnormal situations.

[0021] S120. When the cockpit smoke concentration cannot meet the test requirements due to the open-cabin configuration while the aircraft is in normal air conditioning system operation mode, the degraded air conditioning system operation mode is selected as the equivalent severe verification condition. The degraded operation mode reduces the cockpit ventilation to less than 50% of the normal ventilation by shutting down a cooling component or reducing the amount of engine bleed air.

[0022] The normal operating mode of the air conditioning system refers to the state where all cooling components of the air conditioning system are engaged, resulting in the maximum airflow. In this mode, the through-cabin configuration makes it difficult for cockpit smoke to accumulate to the concentration required for the test. The through-cabin configuration refers to an amphibious aircraft where the cockpit and the rear through-cabin are not separated by an airtight partition, and the two spaces are interconnected. The degraded operating mode refers to an air conditioning system operating state where, compared to the normal operating mode, the cockpit ventilation is reduced to less than 50% of the normal ventilation by shutting down one cooling component or reducing the amount of engine bleed air. The equivalent severity verification condition refers to selecting the degraded operating mode as the verification condition for flight testing. Its equivalent severity lies in the fact that the ventilation volume is small and the smoke extraction time is long in the degraded operating mode. Therefore, if the smoke extraction time in the degraded operating mode meets the airworthiness requirements, the smoke extraction time in the normal operating condition (large ventilation volume) will necessarily be shorter, also meeting the requirements, thus achieving equivalent verification of the normal operating condition. The number of engine bleed air refers to the number of bleed air ports through which the aircraft engine supplies compressed air to the air conditioning system.

[0023] Specifically, the airflow parameters of the aircraft's air conditioning system are obtained. When it is determined that the smoke concentration in the cockpit area cannot reach the preset test threshold due to the through-cabin configuration under normal air conditioning system operation mode (i.e., all cooling components are operating), the degraded air conditioning system operation mode is selected as the equivalent severity verification condition. The equivalent severity verification condition refers to: shutting down one cooling component or reducing the amount of engine bleed air, reducing the cockpit ventilation to less than 50% of the normal ventilation, thereby allowing smoke to accumulate in the cockpit area to the required test concentration. The criterion for determining equivalent severity is: under the same smoke output, the greater the ventilation, the greater the airflow through the cockpit per unit time, and the faster the smoke exhaust rate. Therefore, the smoke exhaust time under the degraded air conditioning system operation mode (degraded condition) constitutes a conservative upper limit for the smoke exhaust time under normal operating conditions; if the smoke exhaust time under the degraded condition meets the airworthiness criteria, then the smoke exhaust time under normal operating conditions must also meet the criteria. By defining equivalent severe verification conditions, it is possible to avoid equipping ultra-large capacity smoke generators to achieve the test concentration in a large cabin space. The test can be completed using the aircraft's own air conditioning capabilities, thus improving experimental efficiency.

[0024] It should be noted that the smoke extraction time in the ground test also constitutes a conservative upper limit for the smoke extraction time in the flight test. Under ground conditions, the pressure difference between the inside and outside of the cockpit is small, and the smoke extraction driving force and air exchange rate are lower than in the high-altitude cruise state. The success of the ground test verifies the correctness of the equivalent severity analysis from another dimension, which can further enhance the reliability of the conclusions.

[0025] For example, the criterion for determining the equivalence severity is: under the same smoke volume, the air supply flow rate of the air conditioner is proportional to the air exchange rate of the cockpit, and the air exchange rate of the cockpit is proportional to the smoke exhaust rate. Therefore, the smoke exhaust time in the degraded working mode constitutes a conservative upper limit of the smoke exhaust time under normal working conditions.

[0026] S130. Establish a graded smoke extraction procedure, which includes a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure uses the air conditioning system to ventilate and extract smoke during normal operation. The emergency smoke extraction procedure uses the pressure difference between the inside and outside of the cabin to quickly extract smoke by pressing the emergency depressurization switch. The decision-making authority for switching between graded smoke extraction procedures is given to the flight crew.

[0027] The tiered smoke extraction procedure can refer to a strategy system consisting of a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure involves expelling smoke through normal ventilation airflow from the air conditioning system while maintaining normal cabin pressurization. This procedure results in a slower smoke extraction rate but does not cause drastic changes in cabin pressure. The emergency smoke extraction procedure involves pressing an emergency depressurization switch, utilizing the pressure difference between the inside and outside of the cabin to rapidly expel cabin air through exhaust valves, achieving rapid smoke extraction. This procedure alters cabin pressure but results in a faster smoke extraction rate. The flight crew refers to the team of pilots performing the flight mission.

[0028] Specifically, a tiered smoke extraction strategy is constructed, including normal smoke extraction procedures and emergency smoke extraction procedures. The normal smoke extraction procedure uses the air conditioning system for normal ventilation to expel smoke while maintaining the normal operation of the cabin pressurization system. The emergency smoke extraction procedure relies on the emergency depressurization function of the cabin pressure regulation system, which has been independently verified in dedicated flight tests, confirming its normal function and safety controllability. The emergency smoke extraction procedure is initiated by the flight crew or ground monitoring personnel based on real-time conditions. By pressing the emergency depressurization switch, the pressure difference between the inside and outside of the cabin drives the cabin air to flow out rapidly through the exhaust valve, achieving rapid smoke extraction. The decision-making power for the tiered smoke extraction procedure is given to the flight crew. While manually operating the aircraft, the flight crew autonomously decides whether to switch from the normal smoke extraction procedure to the emergency smoke extraction procedure, and also autonomously decides the timing of initiating descent, based on the current impact of smoke on instruments and external visibility, and the difficulty of maintaining the aircraft's attitude. This grants the crew flexible decision-making power, preventing fixed procedures from failing under extreme conditions. By employing a tiered strategy, a balance can be struck between smoke extraction efficiency and flight safety. Normal smoke extraction is gentle but slow, while emergency smoke extraction is rapid but alters cabin pressure. The crew can choose the optimal method based on the actual situation, effectively controlling test risks.

[0029] For example, in a graded smoke extraction procedure, the flight crew may decide whether to switch from a normal smoke extraction procedure to an emergency smoke extraction procedure based on factors such as the degree of impact of the current smoke on the visibility of the instrument panel, the degree of impact on the external view, and the difficulty of maintaining the aircraft's attitude manually.

[0030] S140. Perform flight tests under equivalent severe verification conditions, release smoke into the cockpit, and record the start time of smoke exhaust when the smoke concentration reaches the test requirements. The flight crew then executes a graded smoke exhaust procedure and records the end time of smoke exhaust.

[0031] The start time of smoke exhaust can be the instant during flight testing when the smoke concentration reaches the test requirements (confirmed by the flight crew via optical signals), at which point the test personnel shut off the smoke generator and record the data. This instant serves as the starting point for smoke exhaust timing. The end time of smoke exhaust can be the instant when the residual smoke no longer affects the flight crew's operations, recorded as the ending point for smoke exhaust timing.

[0032] Specifically, flight tests can be conducted as follows: The aircraft takes off according to normal procedures, climbs to the predetermined cruising altitude, establishes a stable level flight state, pressurizes the cabin to the normal operating pressure differential, the crew confirms that oxygen masks are worn, communication equipment is functioning properly, cockpit lighting is kept on, and test personnel confirm that the onboard monitoring of the cockpit smoke exhaust video signal is normal; under the determined equivalent severe verification conditions, the air conditioning system is set to degraded operating mode; the smoke generator is activated to release smoke into the cockpit, and the flight crew can choose to close their personal ventilation nozzles during the smoke generation phase to assist the smoke in gathering towards critical areas; when the flight crew confirms that the smoke concentration has reached the required level (which can be determined by optical signals), the test personnel close the smoke generator and record this moment as the smoke exhaust start time; the flight crew executes the graded smoke exhaust procedure; after the smoke exhaust operation is initiated, the flight crew can choose to open their personal ventilation nozzles to use their directional airflow to create a local clean area on their face; when the residual smoke no longer affects the flight crew's operation, the smoke exhaust is considered to be over, and the smoke exhaust end time is recorded to ensure test efficiency and safety.

[0033] For example, during flight testing, an optical signal transmission link independent of the airborne communication system is also established. When the flight crew cannot clearly identify the characters displayed on the instrument panel due to the smoke concentration reaching the test requirements, the flight crew uses a fluorescent stick of a predetermined color or a light-emitting device to emit a visual signal to notify the test personnel to turn off the smoke generator and record the start time of smoke exhaust. The usage specifications of optical signals have been completed in practical training during emergency drills.

[0034] It should be noted that the optical signal transmission link does not rely on the aircraft's electronic communication system and can still operate reliably even in a smoke-filled cockpit where communication may be interfered with. This signal specification has undergone multiple practical training exercises in crew emergency drills to ensure flawless execution in real-world testing.

[0035] For example, during the smoke generation phase, the flight crew may choose to close their personal ventilation nozzles to help the smoke accumulate in critical areas of the cockpit; after the smoke extraction operation is initiated, the flight crew may choose to open their personal ventilation nozzles to use their directional airflow to create a localized clean zone on their face and accelerate the restoration of vision.

[0036] Based on the fact that the smoke exhaust time in the degraded operating mode does not exceed the airworthiness time limit, and the verification of the inverse relationship between ventilation volume and smoke exhaust time in ground tests, it is determined that the smoke exhaust time under normal operating conditions also meets the requirements, and it is concluded that the cockpit smoke exhaust capacity meets the airworthiness requirements.

[0037] The airworthiness time limit can refer to the maximum permitted time for cockpit smoke extraction as stipulated in the Civil Aviation Administration of China (CAAC) regulations and related airworthiness standards, such as 180 seconds (3 minutes). Cockpit smoke extraction capability refers to the cockpit's ability to extract smoke within a certain timeframe to a level that does not affect flight crew operations. Airworthiness requirements can refer to the provisions of Section 25.831(d) of Part 25 of the CAAC regulations, which states that if there is a reasonably likely dangerous amount of smoke to accumulate in the cockpit area, the cockpit must be able to rapidly extract the smoke under full pressurization without exceeding safe depressurization limits.

[0038] Specifically, the smoke extraction time from the start to the end of the extraction process can be calculated, and the peak cabin altitude and rate of change of cabin altitude can be checked to see if they are within the aircraft certification limits. If the smoke extraction time under the degraded condition does not exceed the time limit stipulated in the airworthiness regulations, and the cabin altitude and rate of change are within the safe range, then it is determined that the degraded condition meets the requirements, and the smoke extraction time under the normal condition must be shorter, thus concluding that the cockpit smoke extraction capability meets the airworthiness requirements. If the ground test has completed the smoke extraction time verification and the results meet the requirements, this result serves as auxiliary support for the flight test conclusion, verifying the consistency of the smoke extraction capability from both ground and flight dimensions.

[0039] In this embodiment, a ground test of the cockpit smoke extraction was conducted. With the aircraft ground-based and stationary, the smoke extraction function was verified under both normal operating conditions of the dual-cooling-component and single-cooling-component air conditioning systems. Smoke extraction time data was obtained under both conditions to verify the inverse relationship between ventilation volume and smoke extraction time. A dedicated flight test of the emergency depressurization function of the cabin pressure regulation system was also performed to independently verify the safety of emergency depressurization. Emergency drills were conducted with the flight crew, thus establishing a safety baseline for the flight test. Pilots could gain an initial understanding of the smoke concentration and the air conditioning system's smoke extraction capability, enhancing the crew's confidence in the smoke extraction test. When the cockpit smoke concentration could not meet the test requirements due to the open-cabin configuration while the aircraft was in normal air conditioning system operating mode, a degraded air conditioning system operating mode was selected as an equivalent severe verification condition. The degraded operating mode reduced the cockpit ventilation to less than 50% of the normal ventilation by shutting down one cooling component or reducing the amount of engine bleed air. This avoids the need for an ultra-large capacity smoke generator to achieve the test concentration in the large open-cabin space, allowing the test to be completed using the aircraft's own air conditioning regulation capabilities. A tiered smoke extraction procedure was established, comprising a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure utilizes the normal operation of the air conditioning system for ventilation and smoke extraction, while the emergency smoke extraction procedure utilizes the pressure difference between the inside and outside of the cabin to rapidly extract smoke by pressing an emergency depressurization switch. The decision-making authority for switching between the tiered smoke extraction procedures is granted to the flight crew, preventing the fixed procedure from failing under extreme conditions. Flight tests were conducted under equivalent severe verification conditions, releasing smoke into the cockpit. When the smoke concentration reached the test requirements, the start time of the smoke extraction was recorded. The flight crew then executed the tiered smoke extraction procedure, recording the end time of the extraction. This improved test efficiency and safety. Based on the fact that the smoke extraction time in the degraded operating mode does not exceed the airworthiness time limit, and the inverse relationship between ventilation volume and smoke extraction time verified by ground tests, it was determined that the smoke extraction time under normal operating conditions also meets the requirements. This leads to the conclusion that the cockpit smoke extraction capability meets airworthiness requirements, ensuring the reliability of the conclusion and providing a solid basis for airworthiness certification. This invention establishes a safety baseline through progressive testing. When it is determined that the smoke concentration of the air conditioning system cannot meet the test requirements under normal operating conditions due to the through-cabin configuration, a degraded operating mode is selected as the equivalent severe verification condition. A graded smoke exhaust procedure including normal smoke exhaust and emergency smoke exhaust is constructed and the crew is given autonomous decision-making power. Flight tests are performed under the degraded operating mode. Based on the smoke exhaust time meeting the requirements under the degraded operating mode, it is determined that the normal operating conditions also meet the requirements, and an airworthiness compliance conclusion is drawn. This achieves efficient and safe verification of the airworthiness of smoke exhaust in the cockpit of an amphibious aircraft with a through-cabin configuration, overcoming the problems of smoke accumulation difficulties under through-cabin configuration, high safety risks in testing without autopilot, and lack of a progressive verification system.

[0040] For example, a certain type of amphibious aircraft can be used as the subject to further illustrate the method for verifying the airworthiness of the cockpit smoke exhaust of the through-cabin configuration amphibious aircraft in this embodiment.

[0041] The cockpit of this aircraft is connected to the rear through-cabin and does not have autopilot functionality. It is necessary to demonstrate compliance with CCAR25.831(d). The specific process of the smoke exhaust airworthiness verification method for the cockpit of the through-cabin amphibious aircraft involved in this example can be as follows.

[0042] Step 1, Progressive pre-trial preparation and risk mitigation: Before the flight test, complete the following preparations in sequence: a) Ground test of cockpit smoke exhaust: With the aircraft ground-based and stationary, ground smoke extraction tests were conducted according to a predetermined plan, under two operating conditions: normal operation of both cooling components and normal operation of a single cooling component in the air conditioning system. The test results are shown in Table 1 below.

[0043] Table 1 Results of Ground Smoke Exhaust Test The test results show that the smoke exhaust time is less than 3 minutes (180 seconds) under both operating conditions, which meets the airworthiness criteria requirements.

[0044] The aforementioned ground test data provided crucial support for subsequent flight tests from three dimensions: First, the correctness of the equivalence severity logic was verified. The ventilation volume of the single-refrigeration-component operating condition is only 50% of that of the dual-refrigeration-component operating condition, and its smoke extraction time (127 seconds) is approximately 2.2 times that of the dual-refrigeration-component operating condition (57 seconds). There is a clear inverse relationship between the air conditioning supply flow rate and the smoke extraction time—the smaller the ventilation volume, the longer the smoke extraction time. This directly confirms the equivalence judgment logic upon which this invention is based: the smoke extraction time of the degraded operating condition (single-refrigeration-component) constitutes a conservative upper limit for the smoke extraction time of the normal operating condition (dual-refrigeration-component). As long as the degraded operating condition meets the requirements, the normal operating condition will necessarily meet them.

[0045] Secondly, it confirms that ground tests themselves serve as a conservative boundary for flight tests. Under ground conditions, the pressure difference between the inside and outside of the cockpit is small, the smoke extraction driving force is weak, and the air exchange rate is low. The smoke extraction time under the dual-cooling-component ground test was 57 seconds, while the smoke extraction time under the single-cooling-component ground test was only 56 seconds—the smoke extraction speed only became comparable to the degraded flight test under conditions with greater ground ventilation. This further confirms the judgment that "ground tests are more severe than flight tests." The worst-case result of 127 seconds under the single-cooling-component ground test establishes a sufficient safety baseline for flight tests.

[0046] Third, the difference in smoke accumulation time provides operational rationale verification for the selection of degraded operating conditions. Under the single-cooling-component condition, smoke accumulates to the test concentration in only 50 seconds, significantly shorter than the 56 seconds under the dual-cooling-component condition. This indicates that reducing the ventilation volume effectively solves the problem of smoke accumulation in the through-cabin configuration. With the ventilation volume halved, the airflow velocity in the cockpit decreases, making it less likely for smoke to be carried out to the rear through-cabin by the rapid airflow, thus enabling the required test concentration to be achieved in key areas of the cockpit.

[0047] With the successful completion of the ground test, the smoke exhaust function of the air conditioning system has been basically verified, the equivalent severity logic has been supported by measured data, the safety baseline of the flight test has been established, and the crew's confidence in the smoke exhaust capability of the air conditioning system and the rationality of the test plan has been effectively enhanced.

[0048] b) Flight verification of the emergency depressurization function of the cabin pressure regulation system: Prior to the integrated smoke exhaust flight test, a dedicated flight test independently verified the emergency depressurization function. It was confirmed that pressing the emergency depressurization switch resulted in the exhaust valve opening normally, and that the cabin altitude change rate and peak value were within the approved limits. The emergency depressurization operation did not affect normal aircraft handling. This dedicated verification decoupled the safety confirmation of emergency depressurization from the smoke exhaust effectiveness verification, avoiding the superposition of risks.

[0049] c) Emergency drills for the crew: The flight crew conducted multiple emergency drills, covering safety protection, execution commands for graded smoke extraction procedures, the proper use of non-verbal optical signals (red and green fluorescent sticks), operational coordination under limited visibility conditions, and abort and exit procedures in abnormal situations. Through repeated drills, the crew developed standardized operating habits before entering actual testing, reducing the uncertainty of testing caused by human factors.

[0050] Step 2, determine the equivalent severe verification conditions: When both cooling components are working normally, the total air supply flow of the aircraft's air conditioning system is approximately 3200 kg / h; when only one cooling component is working, the air supply flow is approximately 1600 kg / h, which is about 50% of the normal operating condition.

[0051] During flight tests, under normal operating conditions with dual cooling units, the open cabin space and more efficient airflow during flight prevented smoke from accumulating in the cockpit area, thus reducing the concentration to meet the requirements for triggering the test. Based on the principle that "ventilation flow rate is inversely proportional to smoke exhaust rate," which has been verified in ground tests, the operating condition with a single cooling unit was determined as the equivalent severe verification condition for the flight tests.

[0052] Step 3, construct a graded smoke extraction procedure: A tiered strategy has been established, comprising normal smoke extraction procedures (normal air conditioning ventilation and cabin pressurization) and emergency smoke extraction procedures (pressing the emergency depressurization switch). The system functions upon which the emergency depressurization procedure relies have been verified through dedicated flight tests. During smoke extraction, the flight crew autonomously decides whether to initiate emergency depressurization and the timing of descent based on the degree of smoke impact on visibility and the difficulty of maintaining aircraft attitude.

[0053] Step 4, Flight Test Execution: The test aircraft conducted flight tests using this method. The aircraft took off at 11:13 and climbed to 7300m and leveled off at 11:30. The air conditioning system was set to single-cooling-component operation mode and dual-engine bleed air mode.

[0054] 11:49:25 Smoke generation begins. During the smoke generation phase, the flight crew closes their personal ventilation nozzles to aid smoke accumulation. 11:50:54 The smoke concentration reaches the test requirements; the pilot uses red and green fluorescent sticks to visually signal the test personnel to shut down the smoke generator, and the test personnel record the start time of smoke extraction. 11:51:00 The crew opens their personal ventilation nozzles. 11:51:17 The flight crew decides to begin descent; 11:51:22 The emergency depressurization switch is pressed to initiate emergency smoke extraction. 11:51:50 The pilot reports that the smoke has been completely dissipated.

[0055] Analysis of experimental results: a) The total time from when the smoke concentration reached the required level to when the smoke was completely dissipated was 56 seconds, which is far less than the 180 seconds required for airworthiness.

[0056] b) During the smoke exhaust process, the cabin height and rate of change in the emergency depressurization mode are both within the limits of the aircraft's airworthiness certification.

[0057] c) During the flight test, the air conditioning system and pressurization system functioned normally, and no abnormalities such as electromagnetic interference were observed.

[0058] Step 5, Equivalence Determination and Compliance Conclusion: Based on the complete data chain from ground and flight tests, the following equivalence determination is made: (1) In the ground test, the smoke exhaust time was 127 seconds under the single refrigeration component condition and 57 seconds under the dual refrigeration component condition, which directly verified the equivalence logic that "the smaller the ventilation volume, the longer the smoke exhaust time"; (2) The worst result of the single cooling component working condition of 127 seconds in the ground test has met the airworthiness criterion of 180 seconds, and the margin is 53 seconds, which provides a sufficient safety bottom line for the flight test. (3) During the flight test, the smoke exhaust time of the single cooling component was 56 seconds, which is much lower than 180 seconds; (4) Since the ventilation volume of the dual-cooling module is twice that of the single-cooling module, the smoke exhaust rate is necessarily faster, and the smoke exhaust time of the dual-cooling module is necessarily shorter than that of the single-cooling module. Therefore, the dual-cooling module can complete the smoke exhaust within 3 minutes under normal operating conditions. (5) Ground test 127 seconds (worst ground test) → Flight test 56 seconds (actual flight test) → Airworthiness red line 180 seconds, forming a complete time chain closed loop.

[0059] Based on the complete evidence chain of the aforementioned progressive verification system—quantitative verification and safety baseline construction of ground tests, independent confirmation of emergency depressurization function, full preparation of emergency drills, actual measurement results of 56 seconds of smoke exhaust during flight tests, and multi-dimensional equivalent severity analysis—it was determined that the aircraft's cockpit smoke exhaust capability meets airworthiness requirements.

[0060] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0061] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for verifying the airworthiness of a cockpit smoke exhaust system for an amphibious aircraft with a through-cabin configuration, characterized in that, include: Conduct ground tests of cockpit smoke exhaust. With the aircraft ground-based and stopped, verify the smoke exhaust function under normal operating conditions of both air conditioning system dual cooling components and single cooling component, obtain smoke exhaust time data under both conditions, verify the inverse relationship between ventilation volume and smoke exhaust time, conduct special flight tests of emergency depressurization function of cabin pressure regulation system, independently verify the safety of emergency depressurization, and organize flight crews to conduct emergency drills. When the cockpit smoke concentration cannot meet the test requirements due to the open-cabin configuration while the aircraft is in normal air conditioning system operation mode, the air conditioning system degraded operation mode is selected as the equivalent severe verification condition. The degraded operation mode reduces the cockpit ventilation to less than 50% of the normal ventilation by shutting down a cooling component or reducing the amount of engine bleed air. A graded smoke extraction procedure is established, which includes a normal smoke extraction procedure and an emergency smoke extraction procedure. The normal smoke extraction procedure uses the air conditioning system to ventilate and extract smoke during normal operation. The emergency smoke extraction procedure uses the pressure difference between the inside and outside of the cabin to quickly extract smoke by pressing the emergency depressurization switch. The decision-making authority for switching the graded smoke extraction procedure is given to the flight crew. Flight tests were conducted under the equivalent severe verification conditions. Smoke was released into the cockpit. When the smoke concentration reached the test requirements, the start time of smoke exhaust was recorded. The flight crew then executed the graded smoke exhaust procedure and recorded the end time of smoke exhaust. Based on the fact that the smoke exhaust time under the degraded operating mode does not exceed the airworthiness time limit, and the verification of the inverse relationship between ventilation volume and smoke exhaust time through ground tests, it is determined that the smoke exhaust time under normal operating conditions also meets the requirements, and the conclusion is drawn that the cockpit smoke exhaust capacity meets the airworthiness requirements.

2. The method according to claim 1, characterized in that, The severity of the ground test is determined based on the following criteria: the external environmental pressure in the ground state is the ground atmospheric pressure, and the pressure difference between the inside and outside of the cabin is lower than that in the high-altitude cruise state, which results in the smoke exhaust driving force and air exchange rate being lower than in the flight state. Therefore, the smoke exhaust time in the ground test constitutes a conservative upper limit for the smoke exhaust time in the flight test.

3. The method according to claim 1, characterized in that, The ground tests were conducted under both normal operating conditions of dual refrigeration units and normal operating conditions of single refrigeration units. By comparing the measured smoke exhaust time under the two conditions, the inverse relationship between air conditioning air supply flow and smoke exhaust time was verified, providing quantitative support for the equivalent severity judgment logic. Among them, the ventilation volume of the single-unit condition is about 50% of that of the dual-unit condition, and its smoke exhaust time constitutes a conservative upper limit for the smoke exhaust time of the dual-unit condition.

4. The method according to claim 1, characterized in that, The specific flight test for the emergency depressurization function shall be conducted independently before the comprehensive smoke exhaust flight test, and shall at least confirm that: the exhaust valve opens according to the predetermined logic after the emergency depressurization switch is pressed, the cabin altitude change rate and the peak cabin altitude are within the aircraft certification limits, and the emergency depressurization operation does not affect the normal operation of the aircraft.

5. The method according to claim 1, characterized in that, The emergency drills cover at least the following: safety protection, training on the execution commands and actions of graded smoke extraction procedures, training on the standard use of non-verbal optical signals, training on the coordination of flight control and smoke extraction operations under limited visibility conditions, and training on abort and exit procedures in abnormal situations.

6. The method according to claim 1, characterized in that, The criteria for determining the equivalent severity are as follows: under the same smoke volume, the air supply flow rate of the air conditioner is proportional to the air exchange rate of the cockpit, and the air exchange rate of the cockpit is proportional to the smoke exhaust rate. Therefore, the smoke exhaust time in the degraded working mode constitutes a conservative upper limit for the smoke exhaust time under normal working conditions.

7. The method according to claim 1, characterized in that, In the graded smoke extraction procedure, the flight crew's decision on whether to switch from the normal smoke extraction procedure to the emergency smoke extraction procedure is based on the following factors: the degree of impact of the current smoke on the visibility of the instrument panel, the degree of impact on the external view, and the difficulty of maintaining the aircraft's attitude manually.

8. The method according to claim 1, characterized in that, During flight testing, an optical signal transmission link independent of the airborne communication system is also established. When the flight crew cannot clearly identify the characters displayed on the instrument panel due to the smoke concentration reaching the test requirements, the flight crew will use a fluorescent stick of a predetermined color or a light-emitting device to emit a visual signal to notify the test personnel to shut down the smoke generator and record the start time of smoke exhaust. The usage specifications of the optical signal have been completed in practical training during emergency drills.

9. The method according to claim 1, characterized in that, During the smoke generation phase, the flight crew chooses to close their personal ventilation nozzles to help the smoke accumulate in key areas of the cockpit; after the smoke extraction operation is initiated, the flight crew chooses to open their personal ventilation nozzles to use their directional airflow to create a localized clean zone on their faces and accelerate the restoration of vision.

10. The method according to claim 1, characterized in that, The aircraft is an amphibious aircraft without autopilot. There is no airtight partition between the cockpit and the rear cabin, and the air supply airflow of the air conditioning system flows from the front to the rear of the cockpit.

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