Bond Testing

Bond Testing

1. Special Equipment Required

   • Meter and two cables
   • Ohmeter/Milliohmmeter
   • 1.2V nickel-alkaline source
   • Test cables are 60ft and 6ft in length
     • 60ft cable has a single spike probe
     • 6ft cable has a double spike probe

2. Method One

   • 60ft cable connected to main earth of the aircraft
     • Refer to AMM for location
   • 6FT cable connected to the points specified in the boding test schedule or AMM
   • Meter gives a reading ohms giving an indication of the resistance of the bond

3. Method Two

   • Test leads in form of duplex spikes/single spikes/crocodile type leads
   • Carry out pre-use check by placing all 4 terminals on a low resistance conductor - meter should indicate zero
   • May be necessary to penetrate conductive coating
   • Current is passed through the resistance
   • Voltage drop across resistance is measured and compared with current flowing
   • If higher reading is obtained
     • Bonding connection should be removed and cleaned
     • Connection refitted and sealed
     • Redo bonding test
     • If required bond value can't be obtained, seek advice from manufacturer

4. Pre-use Checks

   • Full scale deflection of the meter is obtained when two spikes of the 6ft probe are shortened
   • Meter reads zero when the two spikes of the 6ft probe are shorted by the single spike of the 60ft probe