When using the FAA's IACRA system, an online portal used for creating applications for the issuance of a rating, you often have to choose an aircraft type to meet qualifications or to set which aircraft you'll be using during a practical test. When selecting aircraft in IACRA the type designators are different from what I'm used to. For example, a Cessna 172 K model's type designator in my experience is C172K, but in IACRA it's CE-172K. The Beechcraft Sierra would normally be B24R, but it's something like BE-23-BE24R in IACRA.
Where is the FAA coming up with these type designators they're using in IACRA?