Supporting activities for hydraulic SE perform periodic maintenance at prescribed intervals, unless otherwise directed. At this time, samples are taken from all hydraulic SE reservoirs (preferably at a low point drain) and analyzed for particulate level and water content. If the fluid is unacceptable, it is

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recirculation cleaned, purified, flushed, or purged. Hydraulic filter elements that can be cleaned are ultrasonically cleaned or replaced at the prescribed maintenance interval. Because of their large dirt-holding capacity, disposable 3-micron pressure line filters are replaced only upon actuation of their differential pressure indicators. Disposable filters that do not have differential pressure indicators are replaced at the prescribed interval.

Age-controlled, deteriorative hoses used to carry hydraulic fluid in SE units are not to remain in service for more than 7 years beyond the manufacturers cure date. Additionally, hoses of this type that are internally located in the equipment are replaced at each prescribed major rework interval, not to exceed 4 years. The date of the required removal and serial number of the equipment is etched or peened on the hose collar. Replace external deteriorative hoses used to transfer fluid between SE and aircraft or components under test that cannot be positively identified as having been in use for less than 2 years as soon as possible, and at regular intervals thereafter, not to exceed 2 years. The date of required replacement and the SE serial number is etched or peened on the hose collars. Hoses should remain attached to the equipment until replacement is required. Upon completion of periodic maintenance, hydraulic SE is certified as having a fluid contamination level not in excess of Navy Standard Class 3.

FLUID SAMPLING, ANALYSIS, AND DECONTAMINATION

Fluid sampling points and procedures vary with the SE type and model. For specific procedures applicable to the particular equipment, you should refer to NAVAIR 01-1A-17. Run the SE for a minimum of 5 minutes before you take a sample. This results in fluid flow through SE reservoirs, which ensures a uniform distribution of contaminants. On some SE models, you need to return the pressure outlet to the reservoir fill opening to achieve such a flow. Find and gain access to the reservoir drain valve and other sampling points or adapters. You need to remove dirt and other visible contaminants from the exposed part of the drain valve and/or sampling adapter. When taking a sample for a patch or particle patch test, wipe the valve or adapter with a clean, disposable cloth. Then, use the plastic wash bottle in the Contamination Analysis Kit 571414 to flush the fittings with clean trichlorotrifluoroethane solvent (MIL-C-81302), 1,1,1-trichloroethane solvent (MIL-T-81533), or dry-cleaning solvent (P-D-680). When you have finished flushing the fittings, open the reservoir drain valve and allow approximately 1 quart of fluid to drain into a waste receptacle. Without interrupting the flow of fluid, take the required sample by letting an additional 4 ounces of fluid flow into a known clean sample bottle (provided with the contamination analysis kit). Close the drain valve after you remove the sample bottle from the fluid stream. Label the bottle to indicate where you took the sample. Repeat the sample-taking procedure at other specified or available sampling points, collecting each sample in a separate bottle. Visually inspect the fluid collected in the waste receptacle for free water. If free water is seen, decontaminate the system according to applicable procedures.

Normally, contamination analysis of SE fluid samples is accomplished by using the contamination analysis kit. You may use other approved measurement methods, if available or if required. Decontamination of unacceptable equipments is performed by recirculation cleaning, purifying, flushing, or purging, as required; these actions are performed by the supporting activity.

Recirculation cleaning is used when equipment is unacceptably contaminated with particulate matter (in excess of Navy Standard Class 3), but the fluid is otherwise considered satisfactory. In recirculation cleaning, the equipment is self-cleaned using its internal filters, the 3-micron elements in particular. You begin by operating the contaminated SE so maximum circulation of fluid through the equipment reservoir and internal 3-micron filters occurs. Maintain the flow long enough to allow a total flow equivalent to at least five times the total fluid capacity of the equipment reservoir. Monitor all filter differential-pressure indicators throughout the operation. If elements appear to be loaded, check and replace them.

You should resample and analyze the fluid from the reservoir. If improvement is shown, but the contamination level is still excessive, repeat the process. If there is still no improvement, try to find the internal contamination source, such as a failed component. Replace any components you determine to be contaminating the fluid, and continue decontamination by draining, flushing, and refilling the equipment with new filtered fluid. Recirculation clean and resample, as before, to determine acceptability. When you find the fluid samples from the reservoir to be within acceptable limits, recirculation cleaning may be terminated.

Flushing is used to decontaminate SE heavily contaminated with particulate matter, or when the fluid contains a substance not readily removed by the internal filters. To begin the flushing procedure, you drain, flush, and reservice the equipment reservoir using new filtered fluid. If contamination originated at the pump, drain and flush the hoses and lines directly associated with the pump output separately. Operate the equipment so fluid flows through all circuits. Allow output (or return line) fluid to dump overboard into a waste receptacle. Continue flushing until a quantity of fluid equal to the equipment reservoir capacity has passed through the unit. Closely monitor the reservoir level during the operation, adding new filtered fluid, as required. This prevents the reservoir level from dropping below the one-third full point,

Take a sample and analyze the output and the reservoir fluids. If the contamination level shows improvement but is still unacceptable, repeat the flushing operation. If extensive flushing fails to decontaminate the equipment, you should request assistance from the supporting engineering activity. Upon successful completion of system flushing, recirculation clean the equipment for a minimum period. Then, take a sample from the system to verify the contamination level as being acceptable. When you have done this, service the reservoir.

Purging of SE hydraulic systems is performed only upon recommendation from, and under the direct supervision of, the cognizant engineering activity. It is the responsibility of the cognizant engineering activity to select the required cleaning agents, provide detailed cleaning procedures, and perform tests upon completion of purging to ensure satisfactory removal of all cleaning agents. Whenever possible, purging operations are to be accomplished at a naval aviation depot facility (NADEP). Intermediate maintenance activities are not authorized to perform system purging without direct depot supervision.

Navy Support Equipment Common Basic Handling and Safety Manual, NAVAIR 00-80T-96, Commander, Naval Air Systems Command, Washington, D.C., 1 April 81, Change, 1 March 1986.