ATA 24

Aircraft Grounding Points
Several instances have been reported of failing electrical grounding points. These connections have developed significant arcing, enough so that the cables have eroded a hole completely through the bulkhead frames. Compliance with the Service Bulletins 1124-24-120 will help minimize this. The areas to pay special attention to are the grounding cable GND 87, 88, 89 and 90, these are the attached at frame station 383 on the ceiling. Also the external power connection to the airframe, this is located at frame station 402.810. Holes in the frame may not be visible until the cables are removed.