To identify a specific Instrument Approach Chart in either the FAA Terminal Procedures Publication (TPP), or the Department of Defense (DoD) Terminal Low Altitude (TLA) Charts, the FAA uses what they refer to as an internal numbering system.
This identifier on any given approach chart is found in the center of the top margin information area and includes two letters, A and L, followed by three or four numbers, followed by the approval authority for the chart, i.e.: AL-571 (FAA).
Found in the FAA Terminal Procedures Chart Users Guide and the general information legend in both the TPP & TLA, the "AL" stands for "Approach and Landing", however, on a high altitude approach chart, the AL is proceeded by a "J", i.e.: JAL-685 (FAA).
Does anyone know what the "J" stands for?
The chart users guide does not identify its meaning nor can I find any reference that addresses it. My assumption is Jet...but I would prefer to confirm what it stands for.