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The Other Airspace Rules

Remember when airspace rules were about avoiding collisions with other airplanes? Return with me now to those days of yore, when Class B airspace and MOAs were designed to keep us safe, not secure.

Remember when airspace rules were about avoiding collisions with other airplanes? Return with me now to those days of yore, when Class B airspace and MOAs were designed to keep us safe, not secure.

After 9/11/01 and now with the war in Iraq, if we don't strictly comply with airspace rules, we're risking everybody's freedom to fly. Legitimate security concerns drive many restrictions on airspace, but all too often it seems domestic "no-fly zones" are political prizes, a political "nyah, nyah, my target is more important than your target" sought as status by the local politburos. And then there's what happened Sunday in Chicago, when Meigs field was ripped up in the dead of night under the direction of Mayor Daley -- with no prior notice to the FAA, claiming it was done for "security" reasons. So long as we can still fly privately, without politicians literally destroying our airfields, it's a good idea to avoid running into each other.

AIRSPACE ABC's ... And Then Some
Most every pilot is familiar with the "alphabet airspace" of Class B, C, D, E and G; Military Operations Areas (MOAs); Restricted and Prohibited areas, and now Temporary Flight Restrictions (TFRs). But there are "other" types of airspace that exist almost solely for our safety -- airspace types that are not controlled by ATC, and do not require a clearance for entry ... in many cases even radio contact is not required. Let's look at some of the other categories of airspace -- just as vital to ensuring a safe, enjoyable flight.

SOME "OTHER" AIRSPACE INDEED IS MILITARY...
Our nation's warrior-pilots need practice to perform the sorts of missions asked of them in places like Iraq and Afghanistan. Not all military activity occurs in MOAs. Strung between domestic military bases and MOAs, and sometimes far from either, are low-altitude (and less well known) Military Training Routes (MTRs). There are no restrictions on civilian VFR or IFR operations across or along MTRs, but "see and avoid" is the rule when in visual flight conditions.

  • MTR Basics: Generally MTRs extend from the surface to 10,000 feet Mean Sea Level (MSL), providing the military authority to exceed the 250-knots-indicated "speed limit" below 10,000 feet. It's not uncommon for MTRs to pass close to small towns and airports. Trainers, transports and tactical fighters may zip along MTRs at very low level, at very high speeds, often "jinking" and turning unpredictably...
Insider's Tip: I was privileged to ride "back seat" in an Air Force F-15E Strike Eagle in North Carolina about two years ago. We flew an MTR routine known as "five and five" -- 500 knots indicated airspeed at 500 feet above ground level. Keep your eyes open for these camouflaged jets, guys and gals! In fact, on that flight we had to maneuver abruptly to avoid a Cessna 210 that was apparently cruising along at 500 feet above ground level (AGL). I wonder if that pilot ever saw us.
    ...MTRs are plotted as lines on Sectional and IFR low-altitude enroute charts, identified as a "visual" or "instrument" route, and with a three- or four- digit number. Translate the codes and you'll learn that:

    • A VR is a low-altitude MTR used only when the cloud ceiling is 3000 feet or higher AND visibility exceeds 5 miles. Military aircraft will fly the "VR" routes under Visual Flight Rules (VFR).
    • An IR is an MTR that are only flown under Instrument Flight Rules regardless of weather conditions, and may be in use when the weather is worse than "3000 and five."
    • VR or IR charted with a three-digit route number (examples: VR123, IR567) includes airspace from the surface up to (and sometimes above) 10,000 feet.
    • A VR or IR identified with a four-digit number (example: VR3456) extends only from the surface to 1500 feet AGL -- true low altitude routes!

Note: For another intimate look at MTRs, see iPilot Insider Paul A. Craig's article Low and ... FAST!

  • Aerial refueling tracks: In some areas, especially over the Great Plains and the Southwest, you'll find Aerial Refueling Tracks on sectional and low-altitude enroute charts. These are areas where military tankers routinely refueling other military aircraft, and the usual refueling altitudes (in most cases above 10,000 feet) are on the charts. Like MTRs, there are no restrictions on civil flight near aerial refueling tracks, but we're just as responsible as the military to avoid collisions when in visual conditions.
  • Alert Areas. Alert areas are charted to warn of a "high volume" of flight training activity "or an unusual type of aerial activity." They look something like MOAs on the charts, but are significantly different in that civilian instrument flight operations are allowed in alert areas at all times (whereas they are not in active, or "hot," MOAs). Alert areas are generally in the vicinity of large military airfields, especially training bases. Fly into an alert area and you're required to "see and avoid" other airplanes when in visual flight conditions.
  • Warning Areas. Warning areas are depicted on charts in areas where "significant hazards" exist along the coasts of the United States. Warning areas start at three miles offshore and continue outward as plotted, and exist primarily to allow military identification of aircraft approaching our nation, as well as to provide warning to possible military air traffic to pilots flying through the warning areas.
  • Controlled Firing Areas. Controlled firing areas are not charted. They're unique in that the hazardous military activity occurring in the airspace is infrequent, and will stop when the airspace is penetrated -- it's the military's job to keep civilians in controlled firing areas safe.

From The Real World
Some time ago I commanded a crew that "turned keys" on (launched) an unarmed Minuteman II intercontinental missile in a test from Vandenberg Air Force Base, California. Our launch countdown was delayed, among other things, by a light airplane flying into the zone, and a fishing boat (perhaps a mysterious, Soviet-era "intelligence trawler"?) loitering offshore. We just waited until the Cessna flew off and the Coast Guard warned the trawler away, before launching the ICBM.

"OTHER" AIRSPACE
Other (non-alphabet) civilian airspace includes:

  • Local Airport Advisory (LAA) areas. Non-towered airports (or tower-controlled airports when the tower is not in service), but which are served by a Flight Service Station (FSS), will have local airport advisory service. LAA is voluntary to pilots, because it is NOT Air Traffic Control, but participating aircraft will receive advisories on known air traffic, as well as adverse weather updates by radio from the Flight Service Station. Flight Service will not "clear" you for takeoff or landing (it's still a non-towered airport), and pilots are fully responsible for traffic and obstacle avoidance. In essence the FSS operates as a well-trained and informed UNICOM. Use the Common Traffic Advisory Frequency (CTAF) unless a separate frequency is identified for LAA at FSS-but-non-towered airports.
    • Flight Service may also provide Final Guard, especially during times of rapidly changing weather. Final Guard means that Flight Service provides unsolicited updates of runway environment wind and weather conditions from the time a pilot reports "on final approach" until calling "clear of the active," or from "taking the active" for takeoff until reporting "airborne." FSS will update conditions any time the specialist on duty feels the changing weather will affect the safe outcome of a takeoff or landing.

  • Remote Airport Advisory (RAA) airspace. FSS provides remote airport advisory service at "specified high activity" general aviation airports. Reported conditions are valid to with 10 miles of the airport, and Final Guard service is automatically included.
  • Remote Airport Information Service (RAIS) airspace. This is an extension of FSS advisories occurring in airspace around airports during special high-traffic events like small- to medium-sized air shows. Because FSS likely does not have weather sensors on the airshow airfield, weather advisories and Final Guard are not provided. Instead, RAIS consists of known air traffic and special event procedures -- kind of a running Notice to Aviators (NOTAM) commentary.
  • Parachute jump areas. Pilots of skydiving "jump" aircraft operating in the vicinity of non-towered airports are expected to broadcast altitudes and positions from which jumpers are dropped, and delay dropping skydivers when other airplanes are in the area. Nonetheless, pilots in the area of skydiving activity need to watch out for jumpers and maneuvering jump airplanes, which often spiral down rapidly over an airport after calling "jumpers away." Airports with frequent skydiving activity are marked with a parachute jump area symbol on Sectional charts.
  • VFR corridors and Flyways. Many major metropolitan areas have specially charted VFR corridors or flyways, with routes and altitudes for safe flight through high-traffic airspace without the need to contact Air Traffic Control. These routes and altitudes are essentially a "hole" through Class B airspace. Look for charted visual transition routes on the back of VFR Terminal Area charts.
  • Terminal Radar Service Areas (TRSAs): Been flying long enough to remember TRSAs? Almost all TRSA morphed into Class C airspace in the 1990s, but a select few (mainly in North Dakota) for some reason remain as "voluntary Class C airspace." On the chart they LOOK like Class C airspace (except that the lines are black, not red), and radar and separation services are available just like in Class C, but participation is entirely voluntary. Participation is "encouraged" but not mandatory; Mode C equipment and two-way radio contact is NOT required to fly through a terminal radar service area. Watch out for Class D airspace at the TRSA's primary airport, though.
  • National Security Areas: Pilots are requested to "voluntarily avoid flying through" national security areas. Two years ago we never heard of these things, right? Of course, these are now the "do not loiter" areas around dams and nuclear powerplants, and often become mandatory Temporary Flight Restriction areas in times of heightened security.

BOTTOM LINE: There was a time in the not-too-distant past when airspace rules were made to keep us from running into each other. Although these days we're more paranoid about the national security aspects of airspace, don't forget the real reason different types of airspace exist. Besides the Class A, B, C, D, E and F airspace, MOAs, Restricted, Prohibited and Temporary Flight Restriction airspace, there are "other" airspace areas that still exist solely to keep us safe.

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About This Author:
Tom Turner is a widely published author and regular forum speaker at EAA's Oshkosh/Airventure and American Bonanza Society. Tom holds an M.S. in Aviation Safety with an emphasis on pilot training methods and human factors. He has worked as lead instructor at FlightSafety International, developed and conducted flight test profiles for modified aircraft and authored three books including: Cockpit Resource Management: The Private Pilot's Guide and Instrument Flying Handbook (both from McGraw-Hill). His flight experience currently spans 3000 hours with approximately 1800 logged as an instructor. Tom's certificate currently shows ATP MEL with Commercial/Instrument privileges in SEL airplanes.
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