单项选择题
If the compass heading and the magnetic heading are the same then（）.
A.the deviation has been offset by the variation B.there is something wrong with the compass C.the compass is being influenced by nearby metals D.there is no deviation on that heading
单项选择题 If the gyrocompass error is east，what describes the error and the correction to be made to gyrocompass headings to obtain true headings?（）.
单项选择题 Magnetic heading differs from compass heading by（）.
单项选择题 My gyro-compass（）is two degrees east.
