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Even before today's sophisticated GPS navigators, with their large color moving-map displays and direct-to convenience, some pilots would take for granted the staple of visual flight rules navigation -- the sectional aeronautical chart.
A lot of care goes into the production and printing of your folded paper charts. The attention to detail is painstaking. And parts of the process are remarkably similar to the steps that you go through as you plan a cross-country flight.
Perhaps even more significant is the fact that a sectional chart has never failed because of a problem with an aircraft's electrical system.
History of aeronautical charts
Pilots have navigated using VFR charts produced by what is now the FAA's National Aeronautical Charting Office (NACO) since 1926. The predecessor to today's sectional chart was known as the strip airway map. A series of 31 such charts covered the primary air routes in the United States. First off the press in 1927 was Air Navigation Map 105, which covered the area from Kansas City, Missouri, to Moline, Illinois. The 35-cent chart depicted topographic and cultural features such as railroads, roads, and cities. It also showed aeronautical data, including airports, lighted airway beacons, and distance and direction lines that were the forerunners of today's airway system.
If a pilot looked at one of those strip airway maps today, he would immediately be comfortable with it -- its appearance is remarkably similar to that of a contemporary sectional aeronautical chart. The detailed terrain contours look almost identical. You'd notice many more railroad tracks, fewer highways, and even fewer radio navigation facilities; cities would appear smaller than they do today. But the map itself exhibits fidelity and quality that are comparable to today's products.
"That was the talent that was in the organization," said Terry Laydon, NACO manager. "It was truly an art form." He believes that the postal service provided limited aeronautical information before this; early airmail pilots may have been its primary beneficiaries.
To promote interstate air commerce, the Air Commerce Act of 1926 authorized the Department of Commerce to begin publishing aeronautical charts. That responsibility was assigned to the newly formed Aeronautical Branch, which soon became the Bureau of Air Commerce and, later, the Civil Aeronautics Administration -- which eventually was transferred to the Department of Transportation as part of the FAA. But the charts themselves were produced by U.S. Coast and Geodetic Survey, then a bureau within the Department of Commerce. Because the Coast and Geodetic Survey was a well-established charting and printing organization, aeronautical chart production could take advantage of its cartographic and publishing capabilities. "It was a logical fit to make that the aeronautical charting organization as well," Laydon explained.
The Coast and Geodetic Survey and its Aeronautical Chart Division became part of the National Oceanic and Atmospheric Administration (NOAA) in 1970 and remained there until 2000, when Congress transferred the function to the FAA. NOAA's entire printing operation made the move to the FAA, and NACO now prints all of NOAA's marine navigation charts.
VFR charts today
It was soon apparent that strip airway maps weren't going to provide enough coverage, and a series of sectional charts was conceived to encompass the entire United States. The first, covering the Chicago area, was published in December 1930; it took seven years to complete the series. Because these early charts depicted much less territory than current sectionals, they were printed on a much smaller sheet of paper -- and on only one side.
Today NACO produces 54 different sectional aeronautical charts, at a scale of 1:500,000, and 29 terminal area charts (1:250,000 scale). Most are updated and reissued every six months; the 13 sectional charts covering Alaska are revised annually. NACO's Visual Chart Branch also produces 21 world aeronautical charts (1:1,000,000 scale), most of which are revised annually; VFR flyway planning charts, found on the back of most terminal area charts; eight helicopter route charts; and several other special charts, including the Grand Canyon VFR Aeronautical Chart and U.S. Gulf Coast Chart.
Between 15 and 18 different VFR charts are published every 28 days; the time required to update and then print a chart makes it impossible to produce them all at the same time. NACO produces and distributes more than 2.6 million VFR charts per year in addition to some 800,000 Airport/Facility Directories and an array of charts for use by pilots flying under instrument flight rules. The products are available from 2,500 chart agents worldwide, or by subscription.
Why current charts?
Why are charts updated so often, and why should I always use current charts?
The amount of information that changes over the six-month cycle of a sectional chart can be staggering. Airport, obstacle, and airspace information changes most often, but terrain and cultural information also is updated regularly. Lanes are added to roads; reservoirs are created; the yellow tint that denotes a city expands as the city grows. "A lot of railroads are being dismantled or abandoned," added Donna Gallant, manager of NACO's Visual Charting Branch.
Jim Grant, a NACO staff cartographer, said that the New York Sectional is a typical example. Its current edition, effective May 12, 2005, contained 290 changes in aeronautical information -- and another 202 changes in base information, including obstruction, topographical, and cultural data -- from the previous edition, only six months earlier.
Federal Aviation Regulation 91.103, Preflight Action, states that "each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight." Flying with an expired chart could lead to an encounter with an obsolete frequency, an unanticipated tower, or other surprises. To ensure that a chart is current, check the next scheduled edition date printed on its cover or see the Dates of Latest Editions on the NACO Web site.
All available sources
In the same way that pilots are obligated under FAR 91.103, NACO cartographers use all available aeronautical information when they update any VFR chart. The National Flight Data Center issues a daily digest of changes to airport, airspace, control tower, and navaid information. The Obstacle Evaluation Section of NACO's Aeronautical Information Branch provides a weekly list of changes to vertical obstruction data -- new towers are built; existing towers are heightened (or shortened); sometimes one is dismantled. Airspace changes come from the legal dockets that describe the airspace.
Likewise, changes to a VFR chart's base information come from many sources: U.S. Geological Survey topographical maps; the Rand McNally Road Atlas; state and county highway maps; state railroad maps; and aerial photography and satellite imagery accessed via the Internet, among others. Critical sources are the letters, e-mails, and telephone calls received from chart users. "It's very important for customers who are flying around every day to provide that feedback," Grant said. Each chart bears contact information for reporting errors or necessary additions; it's also available online.
The NACO flight edit team overflies the coverage area of each sectional every three or four years, evaluating features from a pilot's perspective -- are they visible from an airplane? -- and adding and subtracting as necessary. "They find new towers, new airfields, new construction -- anything that is a navigational reference or safety issue," Laydon said.
The flight inspection is relied on heavily for information on electrical transmission lines, Gallant noted. "Electrical transmission lines are shown for navigational reference only, and it's hard to tell which ones are important" when looking at a map.
"The visual charts have more data sources than any other charting product," added Janet Myers, assistant manager of NACO's Aeronautical Charting Division.
Plotting the changes
As soon as a sectional chart is printed, a copy is designated as the aero standard and cartographers begin marking it up with changes for the next edition. Additions, changes, and deletions are noted in the proper position on the chart, and then leader lines are drawn horizontally or vertically to the margin, where instructions are written. When it's thoroughly covered with handwritten changes, another standard is begun; a charting cycle can see two, three, or even more. Changes to the base information are handled similarly. One of the challenges that the cartographers face when adding or moving data is making sure that it doesn't overlap other information on the chart.
These standards are sent to a contractor that makes each change manually on the appropriate Mylar film positive for each piece of chart information -- producing a sectional can require up to 53 of these films. The quality control process is extensive; a NACO cartographer checks each piece of film when it's returned from the vendor. Then a copy of the new chart is printed; it receives another thorough check before the OK is given to continue printing.
Charts are produced to standards that are determined by the Interagency Air Cartographic Committee. A binder the size of a phone book details those specifications for each chart product.
Printing and production
A/FDs and most IFR flight publications are printed by outside vendors, but NACO prints the VFR charts itself -- in addition to NOAA nautical charts, U.S. Geological Survey topographic maps, and other products. "Our visual charts are our most complicated product by far," Laydon said. "It's very important for quality control to continue printing them in house."
The presses run two shifts each day. "We've never missed a charting cycle," Laydon noted. "They've been in here on Christmas Day and during snowstorms to make the deadline. It hasn't always been easy." NACO's printing, warehouse, and distribution functions are scheduled to move in November to a new facility in Greenbelt, Maryland, that will combine its current printing facility, located in the Department of Commerce, and the former Geological Survey printing operation.
Changes between cycles
Every day, NACO receives changes to aeronautical and base information on its charts. While major airspace changes -- say, reconfiguration of a metropolitan area's Class B airspace -- are normally scheduled to coincide with aeronautical charting cycles, other changes simply happen. "We take those changes -- the significant ones -- and put them in the back of the A/FD, in the Aeronautical Chart Bulletin, to keep that chart updated," Grant explained. "A lot of pilots aren't aware of that." Significant chart changes are repeated in A/FDs until they appear on a revised chart.
Flip through that portion of an A/FD and you'll see a lot of added obstructions, identified by latitude and longitude. Heights of other obstructions increase. But you'll also see potentially important frequency changes, additions or deletions of airports, and navaid changes. There may be changes to military operation areas, military training routes, warning areas, or other special-use airspace.
Spreading the word
NACO offers a two-hour chart seminar that was presented 93 times during the past year, reaching nearly 7,000 pilots. "Our seminar is very well received -- we get a lot of positive feedback from that program," Grant said. "I've had airline pilots tell me that they learned something. The content changes from year to year, based on the inquiries that we get."
NACO also produces the Aeronautical Chart User's Guide, designed as a reference and a teaching aid. It includes explanations of chart terms and shows all chart symbols, not just the small number of frequently occurring symbols that are shown on chart legends.
Changing times
Charts do see significant additions from time to time. "VFR waypoints are a relatively new feature. They go hand in hand with the GPS to promote positional awareness," Myers said. Primarily located around Class B airspace, many are collocated with established VFR checkpoints so that you can see them from the air. AOPA pushed for the creation of visual waypoints because of the safety benefits that result from improved positional awareness.
"I don't think a lot of flight instruction is given on the subject," Grant added. "It's one of those things that you have to figure out."
AOPA also supported another change -- the addition of instrument approaches for military airfields to civilian terminal procedures publications. That could help civilian pilots flying IFR land safely at a military airport in an emergency -- and makes many of those approaches available for training or practice flights. "That's a perfect example of how our projects change," Laydon said.
And chart production is moving, carefully, into the digital world. "A lot of our charts are automated to a certain degree," Gallant explained. "But our day-to-day efforts are still a manual project."
"There's a lot of interest in making the visual charts a seamless digital product, as vector art, and that eventually will come out of our charting office," Laydon said. "We've got our hands full developing this database, but we've made significant progress in the past year. I'm confident that we will get there." A database-driven digital workflow will allow NACO to create new products more easily, and optimize products for digital moving-map displays.
"I think there will always be paper for at least some part of the aviation community," Laydon said. "They might not always be the primary means of navigation, but redundancy is important -- and a paper chart is an excellent backup, even if the primary navigation is with a digital display."
Mike Collins is editor of AOPA Flight Training.
Want to know more?
Links to additional resources about the topics discussed in this article are available at AOPA Flight Training Online.
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