page_title: VHF omnidirectional range
section_title: Intercepting VOR radials
hierarchical_section_title: VHF omnidirectional range / Using a VOR / Intercepting VOR radials
caption_attribution_description: English: Graphical depiction of how a VOR needle shades the headings necessary to center the needle.
context_page_description: Very high frequency omni-directional range is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons. It uses frequencies in the very high frequency band from 108.00 to 117.95 MHz. Developed in the United States beginning in 1937 and deployed by 1946, VOR is the standard air navigational system in the world, used by both commercial and general aviation. In the year 2000 there were about 3,000 VOR stations operating around the world including 1,033 in the US, reduced to 967 by 2013.
  A VOR ground station uses a phased antenna array to send a highly directional signal that rotates clockwise horizontally 30 times a second. It also sends a 30 Hz reference signal on a subcarrier timed to be in phase with the directional antenna as the latter passes magnetic north. This reference signal is the same in all directions. The phase difference between the reference signal and the signal amplitude is the bearing from the VOR station to the receiver relative to magnetic north. This line of position is called the VOR "radial".
context_section_description: There are many methods available to determine what heading to fly to intercept a radial from the station or a course to the station. The most common method involves the acronym T-I-T-P-I-T. The acronym stands for Tune – Identify – Twist – Parallel – Intercept – Track. Each of these steps are quite important to ensure the aircraft is headed where it is being directed. First, tune the desired VOR frequency into the navigation radio, second and most important, Identify the correct VOR station by verifying the Morse code heard with the sectional chart. Third, twist the VOR OBS knob to the desired radial (FROM) or course (TO) the station. Fourth, bank the aircraft until the heading indicator indicates the radial or course set in the VOR. The fifth step is to fly towards the needle. If the needle is to the left, turn left by 30–45° and vice versa. The last step is once the VOR needle is centred, turn the heading of the aircraft back to the radial or course to track down the radial or course flown. If there is wind, a wind correction angle will be necessary to maintain the VOR needle centred.
  Another method to intercept a VOR radial exists and more closely aligns itself with the operation of an HSI (Horizontal Situation Indicator). The first three steps above are the same; tune, identify and twist. At this point, the VOR needle should be displaced to either the left or the right. Looking at the VOR indicator, the numbers on the same side as the needle will always be the headings needed to return the needle back to centre. The aircraft heading should then be turned to align itself with one of those shaded headings. If done properly, this method will never produce reverse sensing. Using this method will ensure quick understanding of how an HSI works as the HSI visually shows what we are mentally trying to do.
  In the adjacent diagram, an aircraft is flying a heading of 180° while located at a bearing of 315° from the VOR. After twisting the OBS knob to 360°, the needle deflects to the right. The needle shades the numbers between 360 and 090. If the aircraft turns to a heading anywhere in this range, the aircraft will intercept the radial. Although the needle deflects to the right, the shortest way of turning to the shaded range is a turn to the left.
caption: Aircraft in NW quadrant with VOR indicator shading heading from 360 to 090 degrees