Airways, Military Training routes and Operating Areas
A Victor Airway is a special kind of Class E airspace and like highways in the sky. Many powered aircraft follow these routes which connect radio navigation beacons called VOR stations that radiate a signal in all directions. These stations are usually located at or near airfields. North-south Victor Airways have odd numbers while east-west airways have even numbers. These federal or Victor Airways are used by both IFR and VFR aircraft. The airspace set aside for a Victor Airway is eight miles wide with a floor at 1200 AGL. Victor Airways are shown on your sectional by faint blue lines in which is printed the V designation along
Military Training Routes -- MTRs are depicted as thin, light gray lines on the sectional. Each has its own identification, and the identifier has two parts. "VR" means that pilots flying the routes will be flying under visual flight rules. "IR" means the pilots will be flying under instrument flight rules (look out for these guys). The second part of the identifier is either a three or a four-digit number. Four digits means the route will be flown at or below 1500 feet AGL. A three-digit number means the route will be flown both below and above 1500 feet AGL. Thus, VR-1626 means a training route flown under VFR at a relatively low level. IR-141 would be a route flown under IFR conditions at any level. A jet fighter traveling toward you at over 300 miles per hour can be very hard to see, so it's a great idea to keep any local MTRs fixed in the back of your mind, and to be especially alert when operating near an MTR.
Military Operations Area (MOA)- These large areas of the country are shown on your sectional as enclosed by a line of magenta hash marks with a sharp outer edge. Military operations such as training exercises come and go. Permission to fly in an MOA is not required.
Warning Area -- This is a hazardous area that lies over international waters, beyond the three mile coastal limit. Overwater flights by small UAV's into these areas are unlikely.
Alert Area - Shown on the sectional chart in two ways, enclosed by a line of magenta or blue hash marks with a sharp outer edge. An Alert Area may involve high general aviation traffic, unusual air operations or frequent student training. The area will be marked with an explanation. Permission to fly in an Alert Area is not required.
Notice to Airman - This area does not appear in the chart legend, but they are on the chart as a solid blue or magenta line with a set of dots inside. This is significant because they usually depict environmentally sensitive areas. Restrictions are printed in a box on the chart.