Biocide overdose blunder suspected in A321 dual-engine incident

UK investigators probing a serious dual engine problem on a departing Airbus A321 have discovered its fuel system had previously been overdosed with biocide, after a maintenance engineer misunderstood a measurement term. The engineer was confused by the term ‘ppm’ – meaning ‘parts per million’ – while conducting a biocidal shock treatment of the Titan Airways A321’s fuel tanks, as the jet neared the end of a month-long maintenance check. While the anti-contamination treatment required a biocide concentration of 100ppm, no explanation or instruction for calculating the overall quantity featured in the aircraft maintenance manual task, and the engineer resorted to an internet calculator. But he miscalculated the dose and, instead of the correct quantity of just under 0.8kg, used 30kg of biocide. <br/>