The low-frequency radio range also allowed air traffic control to instruct pilots to enter a holding pattern "on the beam", i.e. on one of the low-frequency legs, with the holding fix (key turning point) over the low-frequency radio station, in the cone of silence or over one of the fan markers. The holds were used either during the en route portion of a flight or as part of the approach procedure near the terminal airport. Low-frequency radio holds were more accurate than non-directional beacon (NDB) holds, since NDB holding courses are predicated on the accuracy of the on-board magnetic compass, whereas the low-frequency radio hold was as accurate as the low-frequency radio leg, with an approximate course width of 3°.[1]