formerPrimaryAircraft

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: formerPrimaryAircraft

Indicates that an aircraft previously served as the main or primary aircraft for a given operator or entity, but no longer holds that status.