Operando Neutron imaging is used for the investigation of a planar air-breathing array comprising multiple cells in series. The fuel cell demonstrates a stable power density level of 150 mW/cm(2). Water distribution and quantification is carried out at different operating points. Drying at high current density is observed and correlated to self-heating and natural convection. Working in dead-end mode, water accumulation at lower current density is largely observed on the anode side. However, flooding mechanisms are found to begin with water condensation on the cathode side, leading to back-diffusion and anodic flooding. Specific in-plane and through-plane water distribution is observed and linked to the planar array design. (C) 2016 Elsevier B.V. All rights reserved.