Air bronchogram on chest Xray is typically seen in which of the following condition?

Air bronchogram is commonly seen in consolidation. It occurs due to a patent bronchus containing the air column in the bronchi visible in the skiagram. The area of the lung should be completely airless for visualization of air bronchogram, as in collapse or consolidation. In bronchiectasis, ring shadows of varying sizes can be seen on an Xray. In some cases air fluid levels can also be seen. The thickened airways are sometimes seen as tram line shadows. In post primary tuberculosis, a patchy inhomogenous infiltrate in the apical or posterior segments of upper lobes or the apical segment of the lower lobes is seen in the first phase. Later these lesions enlarge and cavitate. Ref: Textbook of Pulmonary Medicine, Volume 1 By D. Behera page 146. Principles and Interpretation of Chest X-rays By P. A. Mahesh, page 22. Radiological Findings in Skin Diseases and Related Conditions By Mati Kormano, page 89.