Aviation safety investigations & reports

Accredited representative to the Japan Transport Safety Board’s investigation of abnormal engine behaviour during decent involving Boeing 787, VH-VKJ on 29 March 2019

Investigation number:
Status: Completed
Investigation completed


The occurrence

On 29 March 2019 at about 1857 JST (Japan Standard Time),[1] a Boeing 787-8 aircraft, registered VH‑VKJ, was operating by Jetstar as scheduled flight JQ15 from Cairns Airport, Queensland, to Kansai International Airport, Japan. During descent into Kansai, the aircraft experienced engine speed oscillations and temporary loss of thrust on the right and then the left engine. The aircraft landed safely at Kansai at 1919.


The Japan Transport Safety Board (JTSB) was responsible for the investigation of this occurrence. As part of this investigation, the JTSB notified the ATSB as the State of the Operator of the aircraft. In accordance with clause 5.18 of Annex 13 to the Convention on International Civil Aviation, the ATSB appointed an accredited representative to assist the JTSB with the investigation. In order to facilitate that assistance, an investigation under the Transport Safety Investigation Act 2003 was commenced.


The JTSB investigation is now complete and identified the probable cause of the engine oscillations and temporary loss of thrust as being residue from a previous biocide fuel system treatment interfering with the fuel metering of both engines. That biocide treatment, Kathon FP1.5, was loaded into the aircraft’s fuel system two days before the occurrence. The JTSB identified a number of safety actions regarding the use Kathon FP1.5 as a biocide treatment.

The JTSB have released the final report into this investigation, which is available at www.mlit.go.jp/jtsb/airrep.

Any enquires relating to the investigation should be directed to the JTSB: www.mlit.go.jp/jtsb.

With the completion of the JTSB investigation, the ATSB’s assistance activities are also complete and the investigation closed.



The information contained in this update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the JTSB final investigation of the occurrence.



  1. Japan Standard Time =UTC + 9 hours.
General details
Date: 29 March 2019   Investigation status: Completed  
Time: 09:05 UTC (1857 Japan Standard Time)   Investigation level: Systemic - click for an explanation of investigation levels  
Location: near Osaka, Japan    
State: International   Occurrence type: Engine failure or malfunction  
Release date: 23 July 2020   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer The Boeing Company  
Aircraft model B787  
Aircraft registration VH-VKJ  
Serial number 36236  
Operator Jetstar Airways  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Cairns, Queensland, Australia  
Destination Osaka, Japan  
Last update 03 August 2020