Limited Duty Officer Designators

The Limited Duty Officer (LDO) Community is comprised of 28 designators in the surface, submarine, aviation, general series and staff corps communities.
    Officer designator codes are four-digit numbers used to group officers by categories for personnel accounting and administrative purposes and to identify the status of officers.  These codes identify, through the first three digits, the categories in which officers are appointed and/or designated and through the fourth digit, the status of the officers within the various categories.

     To find out the specific duties of each designator a link has been provided: LDO Designators

   611X. . . .Deck-Surface
   612X. . . .Operations-Surface
   613X. . . .Engineering/Repair -Surface
   616X. . . .Ordnance-Surface
   618X. . . .Electronics-Surface
   621X. . . .Deck-Submarine
   623X. . . .Engineering/Repair-Submarine
   626X. . . .Ordnance-Submarine
   628X. . . .Electronics-Submarine
   629X. . . .Communications-Submarine
   631X. . . .Aviation-Deck
   632X. . . .Aviation-Operations
   633X. . . .Aircraft-Maintenance
   636X. . . .Aviation-Ordnance
   639X. . . .Air Traffic Control
   640X. . . .Nuclear Power
   641X. . . .Administration
   642X. . . .Information Systems
   644X. . . .Information Warfare
   645X. . . .Intelligence
   646X. . . .Meteorology/Oceanography
   647X. . . .Photography
   648X . . ..Explosive Ordnance Disposal
   649X. . . .Security
   651X. . . .Supply
   653X. . . .Civil Engineer Corps