How commercial aircraft retirements are determined in Cirium fleet data

This post aims to explain how end-of-life commercial aircraft retirements are determined in the Cirium data research process.

NOTE: A separate Knowledge Base article explains how the Fleets Analyzer Projection feature determines future retirements using a non-researched based approach.

Aircraft end-of-life status is confirmed via two different ways; (i) retirement (planned/managed) and (ii) write-off (attributable to an unplanned incident or accident). Upon confirmation of either state, one of the following Events listed in the table below will be incorporated into the individual histories of aircraft. They will then adopt either “Retired” or “Written Off” Status permanently from the Event Date indicated.

In Cirium data, a Retirement is considered the point at which an aircraft is considered never to return to In Service or Storage Status, for reasons not directly attributable to a loss (Written Off). The following indicators are used to help determine confirmed or forecast retirements:

• Permanent withdrawal of use notifications via government registries,
• Evidence or confirmation of part-out/recycling,
• Airworthiness condition,
• Regular assessment of storage aircraft with consideration of: age, utilization, engine, duration of storage and market outlook for the type.

Retirements can be reported using Fleets Analyzer in two primary ways; either using Aircraft Events, or via the Aircraft module to identify all Retired status aircraft in fleet view (such as presented in the ‘Retirements’ readymade search via the Shared by Cirium folder in Saved Searches). The Metric ‘Total Retirement Events’ when used specifically in Trend mode, provides the ability to report recorded historical and any estimated future retirement events recorded per period over a specified date range such as shown in Figure 1 below.

Airline vs Cirium retirements

The term ‘retirement’ is widely used within commercial aviation and especially throughout the 2020 pandemic, where many aircraft have departed airline fleets earlier than previously scheduled.  However, the meaning of ‘retirement’ when used in an airline context can be different to Cirium’s application of retirements in the fleet data.  Airline retirement announcements often just acknowledge removal of aircraft from operational service and financial reporting but not necessarily confirmation of aircraft end-of-life which is what Cirium sets out to achieve.

A typical data event sequence following an ‘airline retirement’ announcement is with the aircraft entering a period of storage, triggered by application of the ‘Parked’ event.  The aircraft will then typically depart for a specialist storage or maintenance location via ferry flight.  If we are confident that the aircraft is a retirement candidate, then a future ‘Scheduled to be permanently withdrawn from use’ event is added to the aircraft history.  The event date field provides an indication of the retirement timescale expected.  An example of this sequence is shown in Figure 2 below:

Aircraft assigned with a future retirement event can be updated to a confirmed retirement earlier than forecast via application of a ‘Permanently withdrawn from use’ event where further information has been forthcoming e.g. evidence of disassembly. Equally, the aircraft may continue to remain in storage up to and past the initial retirement forecast date set and if we remain confident in the retirement outcome, will extend out the forecast date as necessary.

However, the approach of predicting future retirements is not suitable for every aircraft record. New owners can acquire aircraft following airline retirement for future in-service operations including freighter conversion. In light of this, and with many years of experience detecting secondary transactions while in storage, we always remain cautious about applying immediate retirement or future retirement events, sometimes choosing not to, with this assessed on a case-by-case basis.

Retrospective Retirements

For reasons mentioned above, aircraft can remain in Storage status with a future retirement event until actual retirement is determined. In the absence of evidence received during day-to-day fleet research, aircraft in this storage state get reviewed on a 6-monthly interval (Jan and mid-year) to consider a particular airframes condition, suitability for a potential return in the market and where applicable set to retired. Due to this process, the quantity of retirements reported during a historical time period can increase retrospectively, where confirmation of the retirement (and therefore application of the ‘Permanently withdrawn from use’) is appropriate to be back dated.