The microstructure and the pit initiation sites of new creep age-formable aluminum alloys have been investigated. The alloys have been designed by Starink et al. from the University of Southampton to replace alloy 2024 when used as lower wing skin with the main aim of being creep age-formed [in Proceedings of ICAA9 (2004); Mater. Sci. Forum 396, 601 (2002)]. Microstructural evaluation reveals the existence of several different phases throughout the eleven new alloys. The main phases present are Al20Cu2Mn3, Al2CuMg (S-phase), AlxCuFe4, Cu2FeAl7, and (CuFeMn)Al-6. While S-phase particles have been found to be the predominant initiation sites for pitting corrosion in alloy 2024 [JOM, 53, 29 (2001); J. Electrochem. Soc. 144, 2621 (1997); in Aluminum Alloys 2002, Trans Tech Publications Ltd., Cambridge (2002)] in these new alloys, initiation sites were found to be iron and iron-manganese based particles [AlxCuFe4, Cu2FeAl7, and (CuFeMn)Al-6] for all alloys bar two. Those two alloys contained a majority of S-phase. Furthermore, the manganese-based particles did not initiate pitting corrosion, even when they were present in large quantities. In contrast, titanium based particles were found to initiate pitting corrosion, even when present in only small quantities. The extent of pitting under similar conditions was found to be worse for S-phase initiated pitting than for pits initiated at iron and iron-manganese based particles. (c) 2006 The Electrochemical Society.