Choosing the appropriate Gas Discharge Tubes (GDT) for avionics lightning protection

GDTs are a very effective component to suppress high powered pulsed transients such as lightning. When designing per the datasheet, one would expect a component to operate within the specified ratings. This is not always the case. Some GDTs typically violate the impulse spark-over voltage rating. The authors have noticed a belief in the industry that this is normal for a GDT. GDTs can be found that do perform according to their ratings. The purpose of this article is to dispel any belief by the reader that unpredictability of a GDT's impulse spark-over voltage is just "part of designing with GDTs". However, you do have to test.