Aviation safety investigations & reports

Depressurisation involving Boeing 737, VH-XMO, near Melbourne Airport, Victoria, on 6 July 2021

Investigation number:
Status: Active
Investigation in progress


The ATSB is investigating the depressurisation of a Boeing 737, VH-XMO near Melbourne Airport, Victoria, on 6 July 2021. 

While passing 8,000 ft on descent, the crew received pressurisation system warnings and the cabin depressurised. The engineering inspection revealed an insulation blanket had detached and lodged in the aft outflow valve.

The evidence collection phase of the investigation will include a review and examination of maintenance procedures, maintenance records and the gathering of any other relevant evidence.

A final report will be released at the conclusion of the investigation. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken.

General details
Date: 06 July 2021   Investigation status: Active  
Time: 15:00 UTC   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): Ballarat Aerodrome, 161° T 37Km (FR24)   Investigation phase: Evidence collection  
State: Victoria    
  Occurrence category: Incident  
Report status: Pending   Highest injury level: None  
Anticipated completion: 1st Quarter 2022    

Aircraft details

Aircraft details
Aircraft manufacturer The Boeing Company  
Aircraft model 737-376SF  
Aircraft registration VH-XMO  
Serial number 23488 LN:1352  
Sector Jet  
Damage to aircraft Nil  
Departure point Perth, Western Australia  
Destination Melbourne, Victoria  
Last update 22 July 2021