Aviation abbreviations

Do abbreviations represent grammatical variants?

Principles for formulation of abbreviations that an abbreviation may represent grammatical variants of the basic signification where such application can be made without risk of confusion and the desired grammatical form can be determined from the context of the message

What changes have been made to air traffic abbreviations?

Consequential changes to abbreviations used for air traffic purposes emanating from Amendment 2 to the Eighth Edition of Doc 4444 (PANS-RAC)

Consequential changes to abbreviations used for plain language meteorology messages, emanating from Amendment 14 to Doc 7605 (PANS-MET)