In May 2016, Airbus confirmed that a cracking behaviour identified during quality control checks in 2011 was found in a French A400M's fuselage part; not affecting safety, it could be repaired during regular maintenance/upgrade schedules. The aluminium alloy, known as 7X6, was used in several central frames; its chemistry, along with environmental conditions, led to crack propagation. The alloy was excluded from future aircraft; a retrofit to remove it from early A400Ms was considered, which could take up to seven months.