We present details of the calculation $pp\to W(\to l\nu) \gamma$ process at next-to-next-to-leading order in QCD, calculated using jettiness slicing method. The is based entirely on analytic amplitudes. Because radiation zero, NLO QCD contribution from $gq$ channel as important Born $q\bar{q}$ process, disrupting normal counting leading and sub-leading contributions. also assess importance elec...