Why is there a "-D" circling-only approach at an airport that does not have corresponding -A, -B, and -C approaches?

There are three instrument approaches at SEE (as of 17 June 2021):

• RNAV (GPS) RWY 09L
• RNAV (GPS) RWY 17
• LOC-D

The two RNAV approaches are straight-in to runways 09L and 17, respectively. The LOC-D approach is aligned with runway 27R but has no straight-in minima. The -D in the approach name indicates that fact.1

The fact that the suffix is -D implies the existence of LOC-A, LOC-B, and LOC-C approaches at SEE. These approaches do not exist. Why, then, is the LOC-D approach named that way? Did the other approaches exist at one point and have since been removed?

In general, is there any way to look up the historical instrument approaches at any given airport?

1 7110.65 4–8–1a Note 6: "Alphabetical suffixes with a letter from the beginning of the alphabet; for example, A, B, C, denote a procedure that does not meet the criteria for straight-in landing minimums authorization" and AIM 5–4–5a3(a) "Circling only approaches are identified by the navigational system providing final approach guidance and a letter (e.g., VOR A)."

• I believe that there used to be A, B, and C circling minimums only approaches at SEE (Gillespie). With the implementation of RNAV/GPS straight-in minimums could be achieved and the A, B and C procedures were no longer needed. Can't post this as an answer because I can't find any archived approach procedures for SEE. By the way, multiple approaches with a suffix letter (other than S thru Z - straight-in mins same rwy) don't have to be from the same navaid. (e.g., you could have a VOR-A, LOC-B, and NDB-C at the same airport) Jul 11 at 0:12

"The fact that the suffix is -D implies the existence of LOC-A, LOC-B, and LOC-C approaches at SEE." Actually there is a subtelty: According to Order 8260.19 (or FSIMS 404.g.2), for terminal procedures:

The alphabetical suffix for circling procedures must not be duplicated at airports with identical city names within one state. Regardless of the airport name, successive suffixes must be used for all airports that serve the same city.

In accordance, the suffix must be unique for San Diego city, not for Gillespie Field airport.

Other civil airfields serving San Diego per FAA registration include: Lindbergh Field (KSAN), Brown Field Municipal Airport (KSDM) and Montgomery Field (KMYF). More.

It is possible -A,-B,-C are not used anymore (I've not checked), but -D will be kept for this procedure as long as it exists.

The same question was asked and answered on this blog. The original author, Russ Roslewski, is the one to receive the credit.