Introduction
On 26 February 2020, an Airbus A321-211, registration G-POWN, operated by an unidentified airline, was involved in a serious incident at London Gatwick Airport. The Air Accidents Investigation Branch (AAIB) published Report 1/2021 detailing the investigation.
History of the Flight
The aircraft underwent base maintenance that included a biocide treatment of the fuel system. Following the treatment, the aircraft completed several flights before the incident flight. On the incident flight, the crew experienced engine anomalies, including stall indications. The flight returned to Gatwick.
Injuries and Damage
The report includes a section on injuries to persons (Section 1.2) and damage to the aircraft (Section 1.3), but specific numbers are not provided in the excerpt.
Aircraft and Engine Information
The aircraft is an Airbus A321-211 powered by CFM56-5B3/3 engines. The fuel system and engine components, including the Hydro Mechanical Units (HMUs) and Engine Control Units, were examined. The biocide treatment process and its potential impact on fuel contamination are discussed in detail.
Maintenance and Troubleshooting
Base maintenance included a biocide treatment using Kathon FP1.5 and Biobor® JF. Line maintenance later addressed engine stall messages using troubleshooting procedures from the aircraft manufacturer. The AAIB conducted surveys of the maintenance organizations and reviewed the procedures.
Recorded Data
Flight data and ECAM alerts from the incident and preceding flights were analyzed. The fuel flow characteristics during engine starts showed anomalies post-biocide treatment. ECAM fault alerts were recorded during several flights, including the incident flight.
Investigation Findings
The investigation examined fuel samples, engine components, and the HMUs. Deposits were found within the HMUs, and fuel contamination was identified as a key issue. The AAIB also reviewed the Part-145 maintenance organization’s practices and the effectiveness of the troubleshooting procedures.