I think you might have to list the items in a list then random select an item(line by number) to use. This may however have a parse problem where you are transfering built in code to string types(listing) and back again.(am I sick of parsing problems yes I am)
might have some syntax errors in the following, but something like, (yes this came from Kodiak

)
Code:
List<Damage> DamageList = new List<Damage>
{
new Damage ("ElecBatteryFailure"),
new Damage ("ElecGeneratorFailure")
// add each damage type(note add comma on preceeding line)
};
internal class Damage
{
public string EDamageType { get; set; }
public Damage(string eDamageType)
{
this.EDamageType = eDamageType;
}
}
//random selection
Random rand = new Random();
int i = 0;
if (DamageList.Count > 0)
i = rand.Next(0, DamageList.Count);
aircraft.hitNamed(part.NamedDamageTypes.DamageList[i].EDamageType);
});