With the trend towards miniaturization of aircraft, the size of internal electronic components is decreasing. Especially for high-power servo drives, the electronic devices in their voltage systems are prone to discharge faults in complex environments. Therefore, for PCBs with high integration requirements, it is essential to supplement low-pressure breakdown voltage data for adjacent conductors at small intervals. This paper focuses on the weak points of discharge on PCBs and establishes models for air gap discharge and surface flashover. Through experimental research, the breakdown voltage of different specifications of metal electrodes at low pressure is measured, and the impact of temperature is systematically analyzed on the breakdown characteristics of adjacent conductors. The experiments indicate that the breakdown voltage of the adjacent conductors follows a U-shaped trend in terms of pressure. Different temperatures affect the distribution of breakdown voltage at low pressure. The findings of the experiments can provide a valuable reference for risk assessment of conductor spacing in PCBs for aviation.