diff --git a/src/Instrumentation/newnavradio.cxx b/src/Instrumentation/newnavradio.cxx index c6db1ce88..6c65d2e02 100644 --- a/src/Instrumentation/newnavradio.cxx +++ b/src/Instrumentation/newnavradio.cxx @@ -783,7 +783,7 @@ void GS::update( double dt, const SGGeod & aircraftPosition ) double offset = _targetGlideslope_deg - gsDirect; if( offset < 0.0 ) offset = _targetGlideslope_deg/2 * sawtooth(2.0*offset/_targetGlideslope_deg); - assert( false == isnan(offset) ); + assert( false == SGMisc<double>::isNaN(offset) ); // GS is documented to be 1.4 degrees thick, // i.e. plus or minus 0.7 degrees from the midline: _glideslopeOffset_norm = SGMiscd::clip(offset/0.7, -1.0, 1.0);