News story

AAIB Special Bulletin: Biocide treatment of aircraft fuel

The Air Accidents Investigation Branch has published a Special Bulletin concerning a serious incident involving an Airbus A321 aircraft on 26 February 2020.

AAIB deployment vehicle

The Airbus A321 (registration G-POWN) suffered problems with both engines shortly after take-off from London Gatwick Airport on a positioning flight to Stansted Airport with seven crew members and no passengers on board. The aircraft returned for an immediate landing at Gatwick, which was completed successfully.

The investigation has determined that during biocidal shock treatment to combat microbial contamination, an excessive quantity of Kathon biocide was introduced into the aircraft’s wing fuel tanks, equating to 37 times the maximum permitted dosage. This Special Bulletin contains preliminary information about the investigation and is intended to highlight the importance of using correct procedures when dosing fuel with biocide.

Safety action has been taken by the EASA, the FAA, the manufacturer of the biocide, the manufacturer of the engines, the maintenance organisation that performed the biocide treatment, the operator and the maintenance organisation at Gatwick that released the aircraft for service.

The investigation continues to examine all pertinent operational, technical, organisational and human factors which might have contributed to this serious incident.

A Final Report will be published in due course.

Read the report.

Published 21 April 2020