The analysis of Ca XIX helium-like ion soft X-ray spectra in vicinity of the resonance line at l=3.177 [Å] proved to be very useful in determinations of calcium absolute abundances. This spectral region have been extensively investigated using Bragg Crystal Spectrometers aboard the Solar Maximum Mission (SMM) and Yohkoh spacecraft. The analysis of the line-to-continuum intensity ratios yield however conflicting results as concern the average calcium abundance for flares observed by SMM and Yohkoh spectrometers (Bentley, Sylwester and Lemen, 1997).