criticality analysis Spare parts criticality analysis determines what part needs to be on site based on failure impact on Safety, Environment, Production/Insurance. Likely after review this transformer, after considering all factors such as history of failure and system redundancy, did not meet the requirements to become inventory.
Hindsight however is 20/20 and sadly many critical spares become inventory because of a failure and somebody had to be blamed for the consequences. The Operations/Maintenance and Engineering Departments that should have been included in the original analysis will now have to deal with this issue, they are all good, competent people that deserve our support and understanding. I am certain the post mortem will include a review.