equipment or components by replacing or repairing parts or entire pieces of equipment. Special overhaul work is normally done at the depot level. UPKEEP MAINTENANCE Upkeep maintenance is preventive, corrective, or additive maintenance performed by catapult and arresting gear crew members. It includes servicing, periodic inspection, functional and bench testing, replacement, preservation, and repair of catapult and arresting gear equipment. Standard Upkeep Standard upkeep work is the periodic or scheduled maintenance performed on catapult and arresting gear equipment after a prescribed number of aircraft launches or recoveries or calendar days. Such work is performed in compliance with prescribed inspection or replacement requirements. It is known as scheduled maintenance. Special Upkeep Special upkeep work is done on catapult and arresting gear equipment to improve, change, or restore their capability to perform specific mission functions. Special upkeep maintenance is done by replacement, removal, addition, alteration, or repair of catapult and arresting gear parts or equipment. This work is normally performed without regard to flight operations or prescribed maintenance interval periods. It is known as unscheduled maintenance. MAINTENANCE LEVELS All ALRE (aircraft launch and recovery equipment) maintenance functions are divided into one of three distinct maintenance levels: organizational, intermediate, or depot. To determine at which level a maintenance task must be accomplished, you must refer to the appropriate maintenance, operation, and service manuals. Maintenance tasks are assigned according to the complexity, scope, and range of the work to be performed. This allows maintenance to be performed at the lowest practical level in order to maintain required readiness and material condition. The three levels of maintenance are explained in the following paragraphs. Organizational Maintenance Organizational or O-level maintenance is the maintenance that is normally done by the catapult and arresting gear crews. O-level maintenance tasks are grouped under the following categories: Inspection, operation, and servicing as defined and required by PMS Corrective and preventive maintenance, including on-equipment repair and removal/replacement of defective parts Incorporation of technical directives (TDs), within prescribed limitations Record keeping and reports writing Intermediate Maintenance Intermediate or I-level maintenance is done by designated maintenance activities in support of fleet units. The aircraft intermediate maintenance department (AIMD) on aircraft carriers is an example of such activities. I-level maintenance includes the following functions and services: Repair, test, inspection, and modification of ALRE components and related equipment Manufacture of selected and nonavailable parts Incorporation of technical directives, within prescribed limitations Calibration of designated equipment Depot Maintenance Depot or D-1evel maintenance is maintenance that requires skills and facilities beyond the O- and I-levels of maintenance. It is performed by naval shipyards, commercial shipyards, Naval Ship Repair Facilities, contractor repair, the Naval Air Warfare Center (NAWC), and by voyage repair teams (VRTS) from specified naval aviation depots. D-1evel maintenance supports the lower I- and O-levels of maintenance by providing engineering assistance and performing maintenance beyond the capability of lower level maintenance activities. 6-2