What TYPE of HID Lamp is used?
There are various types of HID lamps. The D1S and D2S are 2 of the most common, with the D1S being the preferred lamp. The reason is that D1S lamps have the ‘igniter’ in the lamp base, whereas D2S have the ‘igniter’ in the ballast. That means that the D2S lamps have a high voltage wire (upwards of 20kV possible!) from the ballast to the lamp that can cause much more ‘noise’ and shock hazard, while the D1S has the high voltage step right at the lamp. D1S lamps for the HIDs in your plane are preferred to minimize radio interference and high voltage on cables.