Narrative:

Shortly after departing ZZZ; just prior to the first turn on the zzzzz SID at [around] 400 feet; we received an ECAM alert from the aircraft. After performing the SID turn and completing the after takeoff checklist; we coordinated with ATC to stay in the local area while we ran the ECAM. [We advised with] ZZZ ATC as we were near ZZZ1 and decided as a crew to divert. There was no abnormal pressurization indication; but as we were level at 3;000 feet; we did not expect to see a pressurization issue. We were well above max landing weight; and elected to burn gas as we had no indication (drag; controllability issues; etc) that would have deemed an immediate and overweight landing necessary. While burning gas; we coordinated with dispatch; our flight attendant teammates; and ATC. We informed the passengers of the situation and our intent to land in ZZZ1. After reaching a gw of 142.2; we proceeded to land on [runway] xxl. We had discussed making as smooth a touchdown as possible; given that should the cargo door be open; [we] were concerned of structural damage of the aircraft. A gentle touchdown occurred and taxied in without incident. Upon arrival; hub mx informed us that the aft cargo door handle was in fact open. It was discovered that a significant issue with the cargo door latch mechanism was present and the aircraft was removed from service. After a plane swap; we continued to [destination] and successfully completed the flight with a delayed arrival.

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Original NASA ASRS Text

Title: A320 First Officer reported diverting to an alternate airport after receiving an ECAM alert related to a cargo door malfunction.

Narrative: Shortly after departing ZZZ; just prior to the first turn on the ZZZZZ SID at [around] 400 feet; we received an ECAM alert from the aircraft. After performing the SID turn and completing the After Takeoff Checklist; we coordinated with ATC to stay in the local area while we ran the ECAM. [We advised with] ZZZ ATC as we were near ZZZ1 and decided as a crew to divert. There was no abnormal pressurization indication; but as we were level at 3;000 feet; we did not expect to see a pressurization issue. We were well above max landing weight; and elected to burn gas as we had no indication (drag; controllability issues; etc) that would have deemed an immediate and overweight landing necessary. While burning gas; we coordinated with Dispatch; our Flight Attendant teammates; and ATC. We informed the passengers of the situation and our intent to land in ZZZ1. After reaching a GW of 142.2; we proceeded to land on [Runway] XXL. We had discussed making as smooth a touchdown as possible; given that should the cargo door be open; [we] were concerned of structural damage of the aircraft. A gentle touchdown occurred and taxied in without incident. Upon arrival; hub MX informed us that the Aft Cargo Door handle was in fact open. It was discovered that a significant issue with the cargo door latch mechanism was present and the aircraft was removed from service. After a plane swap; we continued to [destination] and successfully completed the flight with a delayed arrival.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.