First Aid in Aviation Maintenance

First Aid

• Burns from soldering are likely to be minor and require immediate treatment by cooling the affected area under gently running cold water for at least 5 minutes
• Do not apply creams or ointments to the burn; a dry dressing may be applied to protect the area from dirt
• Seek medical attention if needed
• To reduce the risk of burns, always return the soldering iron to its stand after use, allow joints and components to cool down before touching them, and never touch the element or tip of a soldering iron unless certain it is cold
• If solvent or solder enters the eyes, flush with copious quantities of water, place pads on both eyes, and transport the patient to medical attention

Soldering Tools

Heat Application Methods

• The most commonly used method of heat application for soldering joints in aircraft electrical wiring is an electrically heated, hand-held soldering iron

Soldering Irons

• Types of soldering irons:
  • Instant heat iron: used for general soldering where high heat is required, but generally prohibited from use on electronic equipment
  • Constant heat iron: used for general soldering in Automotive/General Service Equipment (GSE) areas where equipment is not heat sensitive
  • Thermostatically controlled iron: used for general soldering in Automotive/GSE settings, similar to constant heat iron but with a thermostat to control tip temperature
• Soldering iron maintenance:
  • Pass the soldering iron tip through a damp cleaning sponge or wipe on a wiping pad to remove surface dross and excess solder from the working surface
  • Do not shake or ‘whip’ an iron to get rid of dross or excess solder droplets
  • Keep the iron tip clean and loaded with excess solder when not in use

Soldering Iron Tips

• Soldering tips are manufactured from various copper alloys chosen for their high thermal conductivity and excellent heat strength
• Tips are plated with a combination of iron, nickel, and chromium to protect the bare metals from oxidation and dissolution by molten solder
• Tinning (applying solder to the tip after heating) is necessary for a soldering tool tip to readily accept solder
• An iron tip should be tinned prior to soldering a component in a circuit
• Pitting indicates the need for re-tinning, and the tip should be filed smooth before re-tinning

Application of Heat and Solder

• Apply flux-core solder at the exact point between the metal and the soldering iron
• Melt the solder on the joint, not the iron
• Place the soldering iron firmly against the junction, and do not apply heat to the work any longer than necessary to melt the solder on all parts of the joint
• Do not use any more solder than necessary, and do not pile up solder around the joint
• Exercise care with silver-coated wire to prevent wicking during solder application

Heat Application Time

• Do not apply heat to the work any longer than the time necessary to melt the solder on all parts of the joint

Soldering Iron Holder

• When the soldering iron is not in active use, keep it in a holder to protect the operator against burns and the iron against damage

Protection Against Overheating

• Do not allow the iron to overheat
• Disconnect the iron when it is not in use (between operations), or use a heat-dissipating stand that will keep the iron at a constant temperature

Cooling the Solder Joint

• When the solder joint has been made, hold the work firmly in place until the joint has set
• Do not disturb the finished work, as this will result in a mechanically weak joint with high electrical resistance
• Allow solder joints to cool naturally; do not use liquids or air blasts

Wire Tinning

• Wire tinning involves applying solder to the tip of the wire before soldering a component in a circuit

This quiz covers the basics of first aid treatment for common hazards in aviation maintenance, such as burns and solvent exposure. It's a part of CASA Part 66 training materials.