number of broken wires. Replace cables exhibiting rust and development of broken wires in the vicinity of attached fittings. Replace wire ropes evidencing bulges, core protrusions, or excessive reductions in rope diameter. FABRIC OR WEBBING.—Fabric or webbing straps must be visually inspected for cuts, holes, severe abrasions, mildew, dry rot, broken stitches, frays and deterioration. Deterioration may be caused by contact with foreign materials such as oil, fuel, solvents, caustic fluids, dirt, and lye. The existence of any of the above conditions renders the sling unserviceable. Twists, knots, and similar distortions must be corrected before use. STRUCTURAL STEEL OR ALUMINUM.— Visually inspect all terminals, shackles, lugs, and structural members for misalignment, wear, corrosion, deformation, loosening, slippage, fractures, open welds, pitting, and gouges. Examine slides and screw adjusters for burrs, misalignment, and ease of operation. Inspect sling attachment bolts and pins for elongation, wear, deformed threads, and other signs of imminent failure. CHAINS.—Chains will be visually inspected for stretched links, wear, gouges, open welds, fractures, kinks, knots, and corrosion. Chain attachment fittings and adjusters will be examined for security, wear, corrosion and deformation. Lubrication, Transportation, and Storage Requirements Examine and lubricate all slings once a month in accordance with NAVAIR 17-1-114. When transporting slings, they will be carried at all times. Dragging slings over floors, runways, decks, and obstructions can cut or severely abrade the material. This malpractice results in an unserviceable sling. Whenever possible, slings should be stored indoors in a clean, dry, well-ventilated area so as to be protected from moisture, salt atmosphere, and acids of all types. In addition, slings constructed with nylon or other fabric materials will be stored in such a way as to prevent contact with sharp objects, high temperatures, and sunlight. Fabric materials deteriorate rapidly from prolonged exposure to sunlight or excessive heat–severely reducing strength and service life. Where practicable, slings will be securely fastened to overhead storage racks to prevent accidental damage. Avoid laying slings on ash or concrete floors. Hoisting Restrictions There are many restrictions to hoisting for each type of aircraft. Most hoisting restrictions are the same as for jacking aircraft. If you violate any of these restrictions, there is a good chance that you will have an accident, damage the aircraft, or injure someone. The restrictions generally concern aircraft gross weight and configuration. Some of the considerations are access (stress) panels on or off, external stores on or off, and wings, folded or spread. There are many factors that can affect the safety of the aircraft and personnel during hoisting operation. For details on restrictions and for the proper installation of any sling, consult the applicable MIM. Don’t forget that many squadrons have their own local standing instructions for hoisting aircraft that contain additional safety precautions and restrictions. You must know them also. Prior to carrier operation, aircraft hoist points are inspected for serviceability and easy excess in an emergency. For details on how to accomplish this inspection on your aircraft, consult the applicable MIM. AIRCRAFT JACKING Learning Objective: Recognize the procedures for the safe raising and lowering of aircraft by the proper use of aircraft jacks. Identify the various types of jacks presently found in the naval inventory. The following text will familiarize you with the various types of jacks, their use, and general safety procedures. You will become familiar with jack identification, preoperational inspections, and jacking procedures. JACK IDENTIFICATION All aircraft hydraulic jacks are either axle or airframe (tripod) jacks. These jacks use standard, authorized aircraft hydraulic fluid. They have a safety bypass valve that prevents damage when a load in excess of 10 percent over the rated capacity is applied. For example, the safety valve on a 10-ton jack will bypass fluid at 11 tons of pressure. Axle Jacks the Use axle jacks for raising one main landing gear or nose gear of an aircraft for maintenance of tires, 3-37