Airway (aviation)

Source: Wikipedia, the free encyclopedia.
This article is about aviation flight corridors. For walkways, see Jet bridge. For companies that provide air transport services called "airways", see Airline. For other uses, see Airway (disambiguation).
"Flight path" redirects here. For other uses, see Flightpath (disambiguation).
Area Control Center (near San Francisco
, California).

In the United States, airways[1] or air routes are defined by the Federal Aviation Administration (FAA) in two ways:

"VOR Federal airways and Low/Medium Frequency (L/MF) (Colored) Federal airways"[2]

These are designated routes which

intersection
of specific radials of two navaids.

United States

History

To guide airmail pilots on their delivery routes, the

Contract Air Mail routes. These airways were between major cities and identified at night by a series of flashing lights and beacons which pilots flew over in sequence to get from one city to the next.[6] Intermediate fields were located every 30 miles (48 km) in case of emergencies, with at least two landing strips a minimum of 2,000 feet (610 m) in length, and 600 feet (180 m) in width. Rotating airways beacons were erected every 10 miles (16 km).[7] However, these visual airways required the pilots to be in visual contact with the ground, which precluded flying in fog or clouds. Subsequently, the Department of Commerce funded the development of other means of airway navigation.[8]

The first airways to be delineated by radio frequency were based on the old Low-frequency radio range also called the "Four Course Radio Range" or "A/N" system. The pilot listened for the stronger of the Morse codes transmitters ("· –" for "A" and "– ·" for "N", indicating left or right of the course); the objective was to be centered on course hearing a steady tone (the A and N Morse codes merge to form a steady tone when the receiver is equidistant from both transmitters).

Later airways were based on low/medium frequency ground stations, like the

Nassau, Bahamas and transitions through the Florida Keys. A portion of B646 connects Key West to Marathon Key and serves as a bypass for aircraft unable to meet the 15,000 foot minimum altitude along that portion of V3. Finally, G765 (Green 765) connects Key West to Cozumel, Mexico. Colored airways are all depicted in brown on low and high altitude charts produced by the FAA
's Aeronautical Navigation Products.

Boundary

Federal airways is defined to be 8 nmi (15 km; 9.2 mi) wide and usually a floor of 1,200 ft (370 m) above the ground. It does not include the airspace of a prohibited area.[9] Aerobatic flights are prohibited within federal airways.[10]

Victor airways

Low altitude airways (below 18,000 feet (5,500 m)

MSL) that are based on VOR stations, appear on sectional charts, world aeronautical charts, and en route low altitude charts and are designated with the prefix "V" (pronounced victor, hence, victor airways). Victor airways are usually assigned odd route numbers for north–south routes and even route numbers for east–west routes. Route numbers are listed serially if more than one airways share the same route segment.[9]

Jet routes

High altitude airways (from 18,000 feet (5,500 m) MSL to FL450) based on VOR stations are called jet routes; they appear on high altitude charts (that usually do not show topography, as the low altitude charts do) and are prefixed by the letter "J". VOR-based routes are depicted in black on low and high altitude charts produced by the FAA's Aeronautical Navigation Products.[9]

RNAV routes

With the invention of RNAV routes, airway structure no longer has to be based on ground-based navaids; a new naming convention is used. RNAV routes not based on VOR routes in low altitudes are preceded with the letter "T"; high airway routes are designated with the letter "Q". RNAV routes are depicted in blue on low and high altitude charts produced by the FAA's Aeronautical Navigation Products. In addition to the published RNAV routes, if radar monitoring and traffic flow allow, air traffic controllers may approve random RNAV routes for IFR flights.[9]

Europe

Airways are corridors 10 nautical miles (19 km) wide of controlled airspace with a defined lower base, usually FL070–FL100, extending to FL195. They link major airports giving protection to IFR flights during the climb and descent phases, and often for non-jet aircraft, cruise phase of flight. Historically, they were laid out between VORs; however, advances in navigational technology mean that this is no longer a necessity. Each airway has a designator containing one letter and one to three numbers. All airspace above FL195 is class C controlled airspace, the equivalent to airways being called Upper Air Routes and having designators prefixed with the letter "U". If an upper air route follows the same track as an airway, its designator is the letter "U" prefix and the designator of the underlying airway.

In the UK, airways are all class A below FL195 and, therefore, VFR flights are prohibited.

Air corridor

"Air corridor" redirects here. For the Mozambiquean airline, see Air Corridor.

An air corridor is a designated region of airspace that an aircraft must remain in during its transit through a given region. Air corridors are typically imposed by military or diplomatic requirements. During the Berlin Blockade, for example, pilots flying across Soviet-controlled German airspace were required to maintain very specific positioning within air corridors defined by the commander in charge of the airlift. Subsequent flights, both military and civilian, between West Germany and West Berlin during the Cold War were required to remain within their designated corridor or risk being shot down.

Air corridors should not be confused with airways. Airways are navigational aids which a pilot generally may deviate from when circumstances warrant, while compliance with a designated air corridor is mandatory.

Notes

  1. ^ The term airway is used by aviation professionals including the International Civil Aviation Organization (ICAO), but other terms have been used or misused by non-specialist sources, sometimes to mean the same thing.

References

  1. ISBN 9780850451634
    .
  2. ^ "Air Traffic Service Routes - Section 3. Federal Airways". Archived from the original on 2020-10-19.
  3. ISBN 978-0521841405
    .
  4. ^ FAA regulations 5-3-4. Airways and Route Systems in Section 3. En Route Procedures; archived from www.faa.gov, accessed 25 October 2020
  5. ^ Airway (definition)- Airway Description www.skybrary.aero, accessed 25 October 2020
  6. ^ Pilot's Handbook of Aeronautical Knowledge (PDF). U.S. Department of Transportation: Federal Aviation Administration. 2016. p. 1‑4. Retrieved 2021-04-12.
  7. ISBN 0876684851
    .
  8. ^ "The Evolution of Airway Lights and Electronic Navigation Aids". Centennialofflight.net. 1924-07-01. Retrieved 2014-07-28.
  9. ^ a b c d "Chapter 1: The National Airspace System". Instrument Flying Handbook (PDF) (FAA-H-8083-15B ed.). Federal Aviation Administration. 2012. pp. 4–5.
  10. ^ "14 CFR 91.303. Aerobatic flight". National Archives. Retrieved 30 December 2024.
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