Magnetic track 090 to, and including, 179° – odd thousands plus 500 ft (FL075, 095, 115 etc.) Magnetic track 180 to, and including, 269° – even thousands of feet (FL080, 100, 120 etc.) Magnetic track 270 to, and including, 359° – even thousands plus 500 ft (FL085, 105, 125 etc.)