FSX Basler BT-67 Spectrem The "Spectrem" Basler BT-67 is a single specially modified aircraft used world- wide for electromagnetic geophysical exploration. It is operated by Spectrem Air Ltd of Johannesburg, South Africa. The company claims that in over fifteen years of service ZS-ASN has flown in excess of 1,500,000 kilometers with a perfect safety record. FSX model by Manfred Jahn, paint by Daniel Fuernkaess.