The current standard test methods for limiting oxygen volume fraction

theoretical and test research results on limiting oxygen volume fraction for aircraft fuel were systematically summarized

then some suggestions were presented by extensively drawing on previous research results: (1) When N2 inerting was adopted on the ground

12% oxygen volume fraction can be used as the control index of oxygen volume fraction in the fuel tank for RP-3 fuel. (2) For civil aircraft

the control index of oxygen volume fraction in the fuel tank within the flight envelope can be determined

indicating that the limited oxygen volume fraction in the ullage of fuel tank at sea level through 3 048 m was approximately within 12%

with a linear increase from 12% at 3 048 m to approximately 145% at 12 192 m; for military aircraft

it can be considered to add a 20% safety margin on the civilian aircraft standard

the limited oxygen volume fraction increased linearly from 9% at sea level to 12% at 12 192 m. (3) At present

in the development of the inerting system of domestic military aircraft

the requirement of controlling the oxygen volume fraction in the ullage of fuel tank within 9% during the whole flight envelope was debatable

which would directly lead to excessive compensation loss caused by excessive protection.