noun which may take the genitive case particle 'no'
unplanned; unscheduled; outside the plan
Describes something not included in the original plan or schedule; often used with nouns like 支出, 休暇, 妊娠.
計画外の支出が増えて予算が厳しくなった。
Unplanned expenses increased and the budget became tight.
計画外の休暇を取ることになった。
I ended up taking unscheduled leave.