Using VOR Navigation Systems to Help Stay On Course
As a pilot, it’s your duty to know exactly where you are at any given time. Without knowing where you’re located, you may soon find yourself flying into a Class B airspace without receiving clearance first. Every part of the country also contains military operations areas as well as restricted flight areas. Flying into these areas won’t just cost you a reprimand, they may cost you your license and the safety of yourself and the others using the area. If you ever are lost, the most important thing you can do is CONFESS the situation to someone who can help you. Air traffic controllers are usually able to locate you and help get you out of or stay clear of any areas you need to avoid.
The most common tool used for aircraft navigation is the “very high frequency omnidirectional range” system or VOR. There are 3 different types of VOR systems. The basic VOR, VOR/DME and VORTAC facilities. All three work by transmitting a radio signal out from the VOR station in every direction. These “beams” or signals are referred to as “radials” and spread out in all 360 degrees. The signal transmitting out at 270 degrees from the station is called the two-seven-zero radial. This is what you use to figure out where you are located.
One of the drawbacks of the VOR system is the limitations based on line of sight. VOR signals can be blocked by large obstructions such as mountains or other terrain. The A/FD (Airport/Facility Director) will list any known obstructions each VOR station may have. It’s important to check for that when you’re planning on using a VOR. You may find you’re a mile left or right of a perfect signal. If you can’t pick up on the VOR signal, the next step is to gain some altitude. This will almost always clear things up.
There are actually three different types of VOR stations depending on your location and where you’re flying. The first one is the Terminal VOR or TVOR and should only be used when you’re within 25 nautical miles of the transmitting station and below 1000′ above ground level (AGL). The low altitude VOR is designed to be used accurately within 40 nautical miles and between 1000′ and 18,000′ AGL. The last is the HVOR or high altitude VOR. It’s accurate at various altitudes and, depending on topography, up to 130 nautical miles.
VOR stations are only half of the system used to navigate using this approach. The other have is in your aircraft and consists of a radio receiver with an antenna and some sort of VOR indicator to put these transmission in a format you can use. The VOR indicator is a round dial with a white needle that lines up vertically when you’ve put in the correct radial. Your instructor will teach more about how this works.
Most people find the best system for them is GPS. But, don’t become too dependant on it. It’s not a bad idea to always use your VOR’s as a back up, so you can stay fresh on their operation. If you really want to stay sharp, consider the GPS “INOP” and fly with the VOR only. You never know when you’re going to have something go wrong on the GPS and you’ll NEED that old trusty VOR to get you to the nearest airport safely.