"Unscheduled maintenance" refers to repairs or work that needs to be done on something unexpectedly or without being planned in advance. Full definition
Supervised personnel performing scheduled and unscheduled maintenance on AIMD equipment, parts, and related tools during two deployments in support of the Global War on Terrorism. (jobhero.com)
Responsible for the launch, recovery, servicing, inspection and scheduled / unscheduled maintenance of P - 3 Orion aircraft. (jobhero.com)
Performed scheduled and unscheduled maintenance for both Intermediate and Organizational level maintenance activities (jobhero.com)