description of when and how to perform the job, even down to what tools, parts, materials, and test equipment will be needed. The MRC is a situation requirement card, which means replacement of the cables is accomplished when certain adverse conditions are met, such as maximum allowable service life of the cables, maximum number of shots allowed, or reaching the maximum number of broken wires allowed before replacement becomes necessary. Inspection Criteria: The cables are locally sub- jected to severe atmospheric conditions produced by heat and steam, which are destructive to the life of the cables. Inspection of the cables must be performed periodically (when scheduled by PMS) for visual damage, such as broken wires, rust, excessive wear, kinks, and dirt. Damage to the cables may be internal as well as external. A wire broken internally may be seen externally as such a wire will eventually work its way to the outside surface. In addition to checking for visual damage to the cables, a record of the number of shots and the length of service must be kept for each set of cables. Any of the following conditions is cause for replacement of the retrieving or towing cables: Five or more broken wires in one rope lay. The length of wire rope in which one strand makes one complete revolution about the core is one rope lay. Twenty or more broken wires in any 30-foot length. The length of service and the number of shots allowed on the cables vary with the type of cables in use. For cables with a steel core, 3,500 to 4,000 shots or 24 months in service, whichever comes first. Replacement of the cables (advance or retract) must be made in pairs and each set must be of the same wire rope construction. This prevents uneven stretch of a pair of cables. Catapult Work (Rough) Logbook A catapult work (rough) logbook may be maintained for each catapult in service, containing all pertinent information acquired daily on the operation, inspection, maintenance, testing, and repair of a catapult. Logbooks may be requisitioned from General Services Administration (GSA) stores under National Stock Number 7530-222-3525. Log entries may include the following: 1. Lubrication oil usage rate (gallons per hundred shots) and lubrication schedules completed. 2. Malfunctions (such as hangfires, slow or runaway shots, premature grab release, failure of dome pressure-reducing valves, sealing strips), the malfunction cause, and any unusual condition accompanying the malfunction. 3. Date, time, and type of inspection conducted, any unusual condition disclosed by the inspection, number of shots on component part and catapult system at the time of the inspection, and special information such as clearance dimensions. 4. All test and maintenance conducted on compo- nents, or any tests pertinent to catapult machinery. 5. All repairs, replacements, or failures of components, along with a full explanation of the corrective action taken. Background history of any previous failures may be included. 6. Service changes that have been incorporated, whether in whole or in part. To maintain continuity, logbook entries should be made each day. If launching, inspections, maintenance, or repairs are not conducted during a 24-hour period, a brief log entry may be made including the status of catapult (READY, STANDBY, or SHUTDOWN), the reason for the catapult being nonoperational, and other pertinent information as directed by the catapult officer. A rough catapult logbook that has been completely filled with entries should be kept for a period of 2 years. Books more than 2 years old should be discarded. SUMMARY In this chapter we have described functions and operations of the major catapult systems, descriptions of charging panels and control consoles, and general maintenance procedures. For a more detailed study of the catapult systems and components, see the applicable NAVAIR technical manual with the latest revisions. 4-76