An Airbus A321 that experienced two days of abnormal engine operations, including surging in the left engine that prompted a MAYDAY call, had been treated with about 38 times the recommended dose of a substance used to combat microbial contamination, the U.K. Air Accidents Investigation Branch (AAIB) says.
The AAIB said in its final report on the Feb. 26, 2020, serious incident at London Gatwick Airport that the excessive concentration of the biocide Kathon was among the causal factors. The excess Kathon in the airplane’s fuel system led to contamination of the engine hydro mechanical units (HMUs) and a loss of the correct HMU regulation of the engines, according to the report, issued in May.
Another causal factor was the use by personnel at the overseas base approved maintenance organization (AMO) of an engine stall troubleshooting procedure that was designed for LEAP-1A32 engines; the incident airplane had CFM56-5B3/3 engines, which required additional steps, the report said….
