main wheels. These screens help prevent damage or injury if a blowout occurs. If the tire is flat, explosive failure of the wheel or tire will not result. However, upon sudden cooling, an overheated wheel may fracture or fly apart, which could hurl bolts or fragments through the air with sufficient speed to injure personnel. Required personnel should approach overheated wheels with extreme caution in the fore or aft directions—never in line with the axle. NOTE: The area on both sides of the tire and wheel, in line with the axle, is where the fragments would be hurled if the tire were to explode. Therefore, it is called the danger area (fig. 5-14). Heat transfer to the wheel will continue until the brake is cooled. Therefore, the danger of explosive failure may exist after the aircraft is secured if the overheated brake is not cooled. The recommended procedure for cooling overheated wheel, brake, and tire assemblies is to park the aircraft in an isolated location. Then, allow the assembly to cool in ambient air for 45 to 60 minutes. Cooling agents should not be used to accelerate cooling unless operational necessity dictates their use. If such an operational necessity were to occur, the cooling should be supervised by someone in the AM rating. WARNING Never use CO₂ to cool overheated brakes. A violent explosion can occur. Liquid Oxygen (LOX) When working with or around liquid oxygen, you must take the following safety precautions: Do not operate liquid oxygen equipment unless you are qualified, licensed, or working under the supervision of qualified personnel. Do not permit smoking, open flames, or sparks in the liquid oxygen handling areas. Do not carry matches in liquid oxygen handling areas. Always call oxygen by its proper name. Do not confuse it with compressed air. Never use oxygen in place of compressed air for any purpose. Handle converters, storage tanks, and transfer equipment with care to avoid damage to the insulating space. Keep work areas and equipment free from oil, grease, or any other combustible material. Keep tools and clothing free from oil and grease. Avoid spilling liquid oxygen on the floor or deck areas. In case of accidental spillage, ventilate the area thoroughly. If the body comes into contact with liquid oxygen or there is reason to suspect some part of the body has been frozen or chilled, thaw the exposed area, preferably by immersion or by bathing it in water that is slightly above normal body temperature. Then wrap the exposed area loosely with a clean, dry dressing. Report to a doctor immediately. Do not apply anything else to the affected area other than a clean, dry dressing. CAUTION Liquid oxygen can explode when it comes into contact with oil or grease. LOX Protective Clothing Protective clothing allows you to work safely with LOX. Wear clothing in the following ways: Wear goggles or safety glasses with side shields or a face shield when handling LOX. If LOX is spilled on clothing, remove the clothing immediately and air it promptly. In general, wear all clothing so that, if there were spillage, the liquid would roll off the clothing and not become trapped in gloves, shoes, or pockets. Other items of protective clothing are plastic or rubberized fabric aprons, high-top shoes or rubber boots, and cuffless trousers worn outside the shoe tops. The clothing should not have pockets, and sleeves and trousers should not be rolled up. Do not handle with your bare hands any tubing or fittings through which LOX is flowing. Wear clean, dry gloves when handling parts of equipment cooled by LOX. Use loose-fitting leather gloves so they can be thrown off quickly if any of the LOX gets into them. 5-21