If installed means that the item is either optional or is not required to be installed on all aircraft covered by the MMEL.
If installed. – means the listed item of equipment is either optional or is not required to be installed on all aircraft covered by the MMEL.
If installed means that the item is not required to be installed on all aircraft covered by the MEL.
Examples of If installed in a sentence
If installed by the City, Developer shall provide funding therefor.