protected during shipment with a sprayable, strippable coating system that conforms to MIL-C-6799, type II. Normally, type II coatings are safe on metal, plastic, or painted surfaces. Also, they are useful for protecting clear acrylic surfaces, such as canopies, against abrasion during maintenance or extended periods of downtime. The type II system consists of a black base coat and a white topcoat that provides heat reflection during outside exposure. Nylon ripcords with finger-size loops are placed about the aircraft before the aircraft is sprayed with this coating. This allows manual stripping of coatings. When properly applied, the coatings can be removed easily. If coatings are sprayed too thin for easy removal, they can be recoated and allowed to dry. The top layer will bond to previous layers, and all layers may be manually stripped in one operation. Corrosion-Preventive Petroleum (MIL-C-11796) MIL-C-11796 is designed for hot application. It is available in two classes, class 1 (hard film) and class 3 (soft film). Both classes consist of corrosion inhibitors in petroleum. They are removed with Stoddard solvent or mineral spirits. Where a hard film is not necessary, you should use class 3. Class 3 is easier to apply and remove, yet it gives the same degree of protection as class 1. Class 1 is for long-time, indoor protection of highly finished metal surfaces and aircraft control cables. Class 3 provides protection for metal surfaces, such as antifriction bearings, shock-strut pistons, and other bright metal surfaces. Class 1 must be heated to 170°F to 200°F before it is applied by brush or dip. For brushing, class 3 material must be between 60°F and 120°F, and for dipping, between 150°F and 180°F. Oil, Preservative, Hydraulic Equipment (MIL-H-46170) Use hydraulic fluid MIL-H-46170 as a preservative fluid to store hydraulic systems and components. It is also used as a testing medium in stationary test stands within a temperature range of -40°F to +275°F. Hydraulic fluid MIL-H-46170 is NOT to be used in portable test stands that are connected to the aircraft. This hydraulic fluid is a fire-resistant, synthetic, hydrocarbon, hydraulic fluid similar to MIL-H-83282. MIL-H-46170 is used as a preservative fluid in systems operating on MIL-H-83282. Lubrication Oil, General-Purpose, Preservative There are several types of lubricating oils, some of which contain preservatives. Each oil is identified by a specification number. Use the correct oil for each situation. The specification number for the oil described in this section is VV-L-800. VV-L-800 oil is used to lubricate and protect piano-wire hinges and other critical surfaces. It is also used when a water-displacing, low-temperature, lubricating oil is required. You may apply VV-L-800 as received by brush, spray, or dip. It is readily removed with dry-cleaning solvent or mineral spirits. Corrosion-Preventive Compound (MIL-C-81309) MIL-C-81309 corrosion-preventive compound is a water-displacing compound and lubricant that must be reapplied frequently. On exposed surfaces, protection lasts about 7 days at best. On internal areas, protection lasts about 30 days. MIL-C-81309 is available in two types—type II and type III. Type II is used for external areas. It forms an effective barrier against moisture when used on B-nuts, linkages, bolts, nuts, ejection seat mechanisms, and canopy locks. When you lubricate an area where there are no pressure lubricating fittings (zerk fittings), such as the piano hinges on access doors and control surfaces, spray with type II preservative compound to clean the area before you apply VV-L-800 preservative oil to remove moisture and contaminants. Type III corrosion-preventive compound is for avionics and electrical equipment usage. It is not for use on exterior areas that will be exposed to the environment. Type III is used primarily on electrical connectors (cannon plugs) and microswitches to remove moisture and contaminants and to prevent corrosion. Packaging and Barrier Materials A minimum of packaging is necessary at the operating activity level. However, critical aircraft and engine areas require shrouding against contamination during maintenance and repair. The fuselage must be sealed when cleaning and stripping materials are used 4-17