Update on our Storage methodology

As of June 1st 2020 Cirium will be making a further adjustment to best reflect the current in service and stored fleets. However, we will not be retrospectively applying the new storage and in service classifications to data prior to June 1st 2020.


Aircraft will now be reflected as entering storage if any of the following criteria are met:

  • 30 days of continuous inactivity.
  • Ferrying to a known storage facility or locations used by airlines during this Pandemic, Bournemouth in the UK an example with British Airways.
  • Airlines announce groundings or retirements of aircraft with immediate effect.
    • or on specific dates before the 30 day tolerance.
  • Aircraft already in storage that are ferried to new storage locations will be tracked and continue to be in storage.
    • the same applying for aircraft placed into maintenance during their storage.

Returning to operation

Aircraft will now be returned to service once we see at least 1 flight or in most cases one pair/set of flights after a period of storage or inactivity, however this will still be reviewed by our dedicated SMEs in our research team. This will also take into account any of the following events that would not trigger a return to service:

  • Ferry flights from one storage location to another or for maintenance after a period of storage
  • Test flights either to and from the same location or as part of ongoing maintenance/cabin re-fits or painting will excluded from return to operation

Additional Points

  • Aircraft previously/currently in service that are placed into Maintenance will not be shown as in storage:
    • If Heavy Checks are being conducted these may take longer than 30 days.
    • Wherever possible we will track these events and confirm aircraft are still in service.
    • The time these checks now take and where they take place can be heavily impacted and so some aircraft on heavy checks may be classified as in storage.
  • Given the fluid nature it is not always possible to confirm definitively the reasons for inactivity.
  • Cirium will also monitor the frequency of the changes we see and will endeavour to mitigate aircraft having two prolonged periods of inactivity either side of 1 flight.
    • There will of course be retrospective updates and made on a case by case basis.

A longer version of this article can be found on the Cirium Thought Cloud.