文献翻译航电设备严重腐蚀的紧急措施--688IT编程网

CHAPTER 10. EMERGENCY ACTION FOR SERIOUS

CORROSION OF AVIONICS EQUIPMENT

1001. GENERAL.

a. This chapter describes emergency corrosion cleaning and treatment procedures to be followed after aircraft or equipment accidents and incidents, particularly those involving exposure to large amounts of saltwater, fire extinguishing agents, industrial pollutants, soot, etc. Immediate action must be taken to remove, clean, dry, and preserve all affected avionics equipment to reduce corrosion damage. When removal of avionics equipment is impractical, in-place cleaning, drying, and preserving should be accomplished.

b. The emergency action procedures outlined in the beginning of this chapter are normally used by the operator only to prevent further corrosion damage. Equipment that has received initial emergency treatment should be forwarded to an avionics repair station for cleaning, drying, inspection, operational checks, and preservation, or returned to the Original Equipment Manufacturer (OEM) for disposition as described later in this chapter.

1002. EMERGENCY RECLAMATION TEAM.

NOTE: In cases involving aircraft accidents, permission to remove equipment

must be obtained from the senior Department of Transportation (DOT) member of

the accident investigation team prior to the start of emergency reclamation

procedures.

a. Goal of an Emergency Reclamation Team. Each organization that operates, stores, maintains, or repairs avionics equipment should have a team identified to handle emergency reclamation situations. The primary goal of the emergency reclamation team is to accomplish those tasks that are necessary to salvage the affected equipment and perform appropriate corrosion control efforts to minimize damage.

b. Emergency Reclamation Team Organization. An emergency reclamation team should consist of a senior team member whose responsibility include directing the salvage, removal priority, and corrosion control efforts for the equipment involved. The size and composition of the remainder of the emergency reclamation team will depend upon the urgency of the situation, type of reclamation effort, and the size of the reclamation task.

1003. EMERGENCY PREPARATIONS.

a. Removal Priority. Each organization that operates, stores, maintains, or repairs avionics equipment should publish an instruction that defines the role and purpose of the emergency reclamation team. The instruction should provide general guidelines for the team to accomplish their task in a safe and efficient manner. It should be reviewed by the emergency reclamation team members on a regular basis, and should include a priority list for the removal and reclamation of equipment and a list of all anticipated tools and materials necessary to accomplish the reclamation task. Table 10-1 provides a recommended guide for a priority removal list.

TABLE 10-1. PRIORITY GUIDE FOR

EMERGENCY REMOVAL OF AVIONICS EQUIPMENT

Equipment

Priority Type

1. Avionics Equipment (radios, computers, radar equipment, etc.)

2. Instruments (aircraft instruments, meters, etc.)

3. Electrical Equipment (switches, wiring, indicator light panels, etc.)

4. Miscellaneous Equipment (mounting racks, etc.)

b. Required Tools, Materials, and Equipment. Immediate availability of the necessary corrosion control tools, materials, and equipment will help to significantly reduce additional damage to the affected equipment. In addition to the corrosion control products listed in Appendix 1, other special support equipment that will be useful and should be readily available are:

(1) Dry nitrogen source,

(2) Dry air source,

(3) Vented drying oven (forced air),

(4) Vented drying oven (bulb-type),

(5) Hot air blowers,

(6) Pump, backpack-style, and

(7) Clean empty 55-gallon drums (removable lid).

c. Production Planning. Whenever possible, all salvaged components of the aircraft or equipment should be treated simultaneously. The most experienced personnel on the emergency reclamation team should be assigned to disassemble and process the affected equipment. This effort will reduce the corrosion potential and other damage to the equipment and ensure that the work is accomplished in a thorough and competent manner. Whenever possible, personnel that normally examine and evaluate this type of equipment should work closely with the disassembly and preservation personnel. This enables non-reclaimable items to be scrapped immediately and only usable components that were exposed to corrosive agents to be disassembled and treate

d. The time saved by this procedure may be used in preserving salvageable components.

1004. EMERGENCY CLEANING PROCEDURES.

CAUTION: Cleaning compounds and solvents identified in Appendix 1 may react

with some encapsulants or plastics used to form wire harness tubing, wire coatings,

conformal coatings, gaskets, seals, etc. Test these compounds and solvents on a

small area for softening or other adverse reactions prior to general application.

Refer to chapter 4, Table 4-3, for further restrictions on these materials.

a. General. Where possible, the primary method of emergency cleaning described in

paragraph 1004b, should be used. When a sufficient quantity of fresh water is not available, use one of the alternate emergency cleaning methods described in paragraph 1004c, steps (1) through (3).

b. Primary Method. The primary method for the removal of saltwater, fire extinguishing agents, et

c., should be used when a sufficient quantity of fresh water is available. The primary method procedures are:

(1) Flush all internal and external areas with clean fresh water. Whenever possible, units or subcomponents that have been removed should be immersed and flushed thoroughly in clean fresh water.

A 55-gallon drum may be used for this purpose. Tilt the unit or subcomponent back and forth to aid in draining off the excess water.

(2) Blow off excess water with not more than 10 psi air pressure or dry nitrogen. Deflect jet of air off interior, back, and sides of enclosure to diffuse.

(3) If there is any evidence of salt or fire extinguishing agents, a second cleaning action should be initiated using a solution of 1 part Aircraft Cleaning Compound to 10 parts of fresh water, conforming to MIL-C-85579, Type II. Scrub the effected areas with the cleaning solution using a brush. Flush thoroughly with fresh water and drain excess. The equipment may be immersed in fresh water to aid in removing hidden contaminants. Tilt the unit or equipment back and forth to aid in draining off the excess water.

(4) Blow off excess water as specified in paragraph 1004b(2).

c. Alternate Methods. The following describes alternate cleaning methods when sufficient fresh water is not available.

(1) Solvent Method.

NOTE: Local air pollution regulations may restrict the use of this and other

solvents. Comply with all local air pollution regulations.

(a) Clean exterior of equipment using a brush and dry cleaning solvent, P-D-680, Type II.

(b) Collect waste solvent from exterior cleaning and dispose of by recycling or as a hazardous waste.

CAUTION: Properly dispose of all hazardous waste in accordance with local

regulations.

(c) Disassemble equipment as required. Clean and dry interior surfaces in accordance with instructions of paragraph 1004b(3) and (4).

(2) Aircraft Cleaning Compound Method.

(a) Apply a solution of 1 part Aircraft Cleaning Compound to 9 parts of fresh water, conforming to MIL-C-85570, Type I. Scrub or wipe interior and exterior surfaces of equipment using a brush or clean cloth until contaminants become intermixed or emulsified. Wipe off all surfaces thoroughly with a clean cloth removing contaminants and cleaner.

(b) Blow off excess solution with not more than 10 psi dry air pressure or dry nitrogen. Deflect the jet of air off interior, back, and sides of enclosure to diffuse.

(3) Water-Displacing Method. The water-displacing method should be used as the last choice of the alternate cleaning methods. Additionally, the water-displacing method is considered only temporary preservation until proper cleaning methods can be accomplished. After application of the water-displacing compound, tag equipment with an appropriate marking indicating the component has been temporarily preserved with Water-Displacing Corrosion Preventive Compound, conforming to MIL-C-81309, Type II, but still requires cleaning.

(a) Blow off excess water and other contaminants from component with not more than

10 psi dry air pressure or dry nitrogen. Deflect the jet of air off interior, back, and sides of enclosure to diffuse.

(b) Totally immerse equipment in a 55-gallon drum of Water-Displacing Corrosion Preventive Compound, conforming to MIL-C-81309, Type II. Tilt the unit or equipment back and forth to aid in removing any water. Immerse the equipment a second time, repeating the tilting to thoroughly coat all surfaces. If total immersion is not practical, spray, brush, or wipe the interior and exterior of equipment with Water-Displacing Corrosion Preventive Compound.

than 10 psi dry air pressure or dry nitrogen. Deflect the jet of air off interior, back, and sides of enclosure to diffuse.

1005. EMERGENCY DRYING AND PRESERVATION.

a. General. Drying and preservation are essential to eliminate any traces of water and to control corrosion until the equipment can be disassembled, inspected, and repaired at an authorized repair station.

b. Drying and Preservation Procedures. The following drying and preservation procedures should be used with the listed drying equipment after cleaning in accordance with paragraph 1004b.

(1) Vented Drying Oven (Forced Air).