Abstract: In the present work, localized corrosion behaviour of aerospace AA2024-T3 aluminium alloy has been investigated using a wide range of electron microscopy techniques. It was revealed that localized corrosion of AA2024-T3 alloy tends to occur in form of intergranular attack. Further, it was also noticed that during intergranular corrosion development, grain-stored energy instead of grain boundary precipitate plays a more crucial role. Intergranular corrosion selectively attacks grain boundaries surrounding grain of higher stored energy rather than that of lower stored energy. The findings could advance the under-standing of intergranular corrosion mechanism of aerospace aluminium alloys and, more importantly, provide theoretical guidance for aerospace alloy design to ensure the safe operation of aircraft.