Before revision: Even so, the submarine must be very near the aircraft's position and close to the sea surface for detection of the anomaly, because magnetic fields decrease as the inverse cube of distance, one source gives a detection slant range of 500 meters .
After revision: Even so, the submarine must be very near the aircraft's position and close to the sea surface for detection of the anomaly, because magnetic fields decrease as the inverse cube of distance, one source gives a detection slant range of 500m .