N4JRI's Radio Pages: Aircraft Monitoring
Knowing the Airspace Around You
For the scanner listener, there are two types of airspace. Uncontrolled Airspace is that in which aircraft don't have to be under FAA control or in radio contact with anyone. Controlled Airspace is that in which all aircraft must be under positive control and in contact with FAA controllers. You can find out what kind of airspace you live beneath by consulting a Sectional Aeronautical Chart.
Class A Airspace - All 18,000-60,000 feet. (Flight Level 180-600) All aircraft at these altitudes must be under positive control and in contact. For most of the continental US, this includes both civilian and military aircraft. Controlling agency is one of the Air Route Traffic Control Centers (ARTCC's). There are three layers of sectors. The low sectors are from ground level to 23,000 feet. The high altitude sectors are roughly from 24,000 to 33,000 feet. Super high altitude sectors are for traffic above 33,000. Super high altitude sectors do not cover the whole US. There they don't exist, the high altitiude sectors handle the sky above 33,000 feet.
Class B Airspace - (Terminal Radar Service Area) This is similar to Class C airspace but larger and more complicated. You find Class B airspace over large cities like Washington, DC, Philadelphia and New York City where several busy controlled airports operate in close proximity. An area of Class B airspace could cover altitudes up to 10,000 feet, and have a radius of 50 miles. Some may have corridors open for VFR planes and/or helicopters. As with Class C, the lower the plane is, the closer it can get to the airspace without radio contact. The shape of this airspace looks like an upside down wedding cake with the large layers positioned above the smaller ones.
Class C Airspace - (Airport Radar Service Area) Within 5 miles of any airport with a control tower, ALL aircraft below 4000 feet must be in contact with that airport's controllers. Aircraft flying between 1200 and 4000 feet must be in contact with Approach/Departure as long as they are within 10 miles of the airport. If you live 7 miles from the center of Class C airspace, a plane flying below 1200' does not have to be in touch with the tower. A plane between 1200 and 4000 feet high must be in contact. Contact is optional over a much greater distance. Many Class C control facilities might cover a 40-mile radius around the airport at altitudes up to 10,000 feet.
Class D Airspace - Found around airports which have a control tower, but no approach control of their own. Controlled airspace is a radius of 5 miles around the airport at altitudes of up to 2500 feet. These airport don't have approach-departure control of their own, but the local FAA Air Route Traffic Control Center (ARTCC) are keeping the arriving and departing flights on track.
Class E Airspace - This is space where IFR flight is taking place, but VFR flights are generally uncontrolled. It includes air routes above 14,000 feet, transit areas between class B, C or D airspace and the aeronautical route system. Designated federal airways count as Class E. Bottom line, IFR flights found here are, as always, under positive control and radio contact. VFR flights are not in contact unless they have requested radar service.
Class F Airspace - Note a US type. Possibly a European type.
Class G Airspace - Uncontrolled airspace, generally at low altitude.
Special Use Airspace
Military Operations Area (MOA) - Areas where military aircraft are training and may need to make aerobatic maneuvers. May be controlled by either an FAA or a military entity. IFR flights are routed around any activity. VFR flights are permitted inside, but must be watchful. These areas generally have names rather than numbers. A very large one in central Virginia is the Farmville MOA.
Warning Area - Offshore areas where aircraft maneuvers or naval gunfire might be encountered. Four Navy FACSFAC agencies monitor and oversee these areas. Here on the east coast, we listen to dogfights on a range located off the coast of North Carolina in Warning Area W-72.
Restricted Area - Areas, primarily military, where non-participating aircraft may transit. Military bases and ranges generally fall under this category. All aircraft in the area must be in contact with the controlling agency. The Dare County bombing ranges near Manteo, North Carolina are located in Restricted Area R-5314.
Prohibited Area - Civilian aircraft are not to enter. The White House is located in prohibited area P-66. Pilots violating these areas are subject to FAA action against their licenses.
The Sky Above My Head:
The N4JRI studios are about 6 miles west of Richmond International Airport (RIC). Here's what you have to listen for if you see a plane above.
34,000-? - Washington ARTCC - Yorktown Sector (super high) 127.425 & 387.050 MHz (when Military or NASA releases for use by FAA)
24,000-33,000 - Washington ARTCC - Hopewell Sector (high) 132.025 & 269.300 MHz
18,000-23,000 - Washington ARTCC - Irons Sector (low) 132.775 & 351.800 MHz (interestingly, most aircraft arriving and departing RIC don't talk on this frequency. They are near adjacent sectors when handed off to RIC Approach/Departure.
10,500-18,000 - Washington ARTCC - Irons Sector (low) 132.775 & 351.800 MHz - Contact is optional here for VFR aircraft, required for IFR.
4,000-10,000 - Richmond (RIC) Approach - West 134.700 & 307.200 - Contact optional for VFR flights, mandatory for IFR flights. The ceiling for mandatory control/contact is 4,000 feet, but for planes who opt for contact, RIC handles things up to 10,000 feet for a radios of 30-40 miles from the airport. (Per letter of agreement with Washington ARTCC)
1,200-4,000 - Richmond (RIC) Approach - West 134.700 & 307.200 MHz (this is the mandatory contact area above my head. Areas above and below this are optional for VFR flights)
Ground-1,200 - Richmond (RIC) Approach - West 134.700 & 307.200 MHz. Contact is technically optional for VFR flights at these altitudes, but the tall buildings force aircraft upwards in altitude. Also, the mandatory contact area for these altitudes is only a mile or so to the east.
Obviously, it pays to think three-dimensional.
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