On 29 March 2019, both engines of a Boeing 787-8 on descent to Kansai malfunctioned in quick succession causing auto ignition to be triggered by sub-idle engine rpm but thereafter, sufficient thrust was available to safely complete the flight just under half an hour after the dual malfunction. The Investigation found that the cause of these malfunctions had been contamination of the fuel system with abnormally large concentrations of residue which could be reliably traced to a routinely applied biocide and which had solidified and intermittently impeded the transfer of fuel from the tanks to the engines.