The author found that the detection missing situation always occurred in the gross-leak test of the accumulative helium mass spectrometry combination test. The gross / fine-leak detection missing situation,as reported in 2013 and 2014 NASA's Hermeticity Correlation Study,also occurs in repetitive tests for different combination tests. For gross-leak test of the accumulative helium mass spectrometric combination test and the combination test by using argon as gross-leak tracer gas and using helium as fine-le...