The parasternal long axis view is a good view to profile the great vessels. In D-TGA, the great vessels can often be seen traveling parallel to eachother in this view. The pulmonary artery can be seen arising from the left ventricle and traveling posteriorly appearing to dive downwards from this view and bifurcating.
Transducer placed on the left sternal border
3rd or 4th intercostal space
Notch pointed towards the patient's right shoulder (11 o'clock)
D-TGA (parallel great vessels, pulmonary artery seen arising from LV and bifurcating)