Is I_MagneticCompass broken?

[salmo]

Can anyone tell me if the I_MagneticCompass paramater type has been broken? My script execution is stopping at this line without an error being thrown, which is very puzzling. Oh, and the aircraft is not null & is an AiAircraft.

if (aircraft != null && aircraft is AiAircraft)
{
    Console.WriteLine("This line executes OK");
    double heading = aircraft.getParameter(part.ParameterTypes.I_MagneticCompass, 0);
    Console.WriteLine("This line fails to execute");
}