民用飞机燃油箱系统闪电防护分析方法研究

民机燃油箱系统的闪电防护是燃油箱安全的重要研究范畴，本文依据FAA的25-146号修正案和咨询通告AC25.954-1，介绍了民用飞机燃油箱系统闪电防护分析方法。在点火源防护分析思路的基础上，针对闪电引起的点火源，在明确飞机闪电分区后，可通过容错类设计或非容错类设计分别开展分析。针对容错类设计，可仅通过证明防护设计特征有效且可靠来表明符合性，无需进一步分析失效概率。针对非容错类设计，通过定性和定量分析法进行评估。在定性分析时，需评估非容错特征失效且引起点火源的概率小于1E-5。在定量分析中，可结合燃油箱可燃性、关键闪电和防护特征失效概率确保闪电引起燃油蒸气点燃的概率为极不可能。同时，根据闪电环境定义的电流振幅和波形对防护设计特征进行有效性验证。

Research on the fuel tank system lightning prevention analysis method for civil aircraft

Civil aircraft fuel tank system lightning prevention is an important research area of fuel tank safety. According to FAA amendment No.25-146 and AC25.954-1, this paper introduces the fuel tank system lightning prevention analysis method. Based on the analysis method of ignition source protection, the ignition source caused by lightning can be analyzed separately through fault-tolerant design and non-fault-tolerant design after clarifying the lightning zoning of aircraft. For fault-tolerant designs, compliance can be demonstrated only by proving that the protection design features are effective and reliable, without further analysis of failure probability. For non-fault-tolerant designs, it can evaluate through by qualitative and quantitative analysis methods. In the qualitative analysis, it is necessary to evaluate that the probability of non-fault-tolerant feature failure and the ignition source is remote. In the quantitative analysis, it needs to combine the probability of the fuel tank flammability, the probability of critical lightning strikes, and the failure probability of protective features to ensure that the probability of fuel vapor ignition caused by lightning is extremely improbable. At the same time, the effectiveness of the protection design features is verified according to the current amplitude and waveform defined by the lightning environment.