For questions about Aeronautical Information Products and Services (i.e. Instrument Flight Procedures, Charts, Aeronautical Data, or NOTAMs) not addressed below please contact the FAA's Aeronautical Information Services through the Aeronautical Inquiry Portal.

Digital Products

• What digital (electronic format) products does Aeronautical Information Services make available?
• How can I get a copy of an electronic chart?
• Can FAA's digital products be used in private industry software products? What are the copyright/licensing regulations for these products?
• Can I use the CIFP (Coded Instrument Flight Procedures) to update my GPS or FMS?
• Why can't I get your digital files sooner than 20 days prior to their effective dates?

Chart Supplements - formerly the Airport / Facility Directory

• How can I update my airport diagram information?
• How can I make a change to the Chart Supplements?

Instrument Flight Procedures

• What is an instrument flight procedure?
• How does FAA develop an instrument flight procedure?
• What data will be required for FAA to produce these Instrument Procedure Charts?
• What shall I expect after the instrument flight procedure is developed?

Chart Discrepancies

• How can I report chart discrepancies?
• Where can I review product errors and see product enhancements?

Chart Users' Guide

• What is the Aeronautical Chart Users' Guide?

Navigation

• Why should I fly with current charts?
• What is the FAA policy for carrying current charts?
• What is the database currency requirement needed for VFR or IFR flight?
• What is the process for establishing Rulemaking (i.e. Class A, B, C, etc., Restricted, etc.) and Nonrulemaking (i.e. Military Operations, Warning, Alert, etc.) Airspace areas on aeronautical charts?

Digital Obstacle File (DOF)

• Is the DOF data considered to be in the public domain? Are there any restrictions on using the DOF data?
• In the DOF, how does one differentiate between a dismantled structure and an existing structure at the same location?
• Why does the City Name field sometimes show "CITY, STATE" instead of the normal "CITY"?
• In your database, is there a field that specifies whether obstructions are single or group?
• Do you have shape files for your DOF data?
• Do you have more specific metadata for your obstacles? (i.e. Is a "sign" a traffic sign, a billboard, etc?)
• Do you have more specific metadata for your "TREE" and "VEGETATION" obstacles?
• Your database does not seem to contain many buildings that exist in a particular area. Does the DOF not include all tall structures?
• Does the DOF contain obstacles for approach procedures (found on the FAA form 8260)? If so, is there attribution that identifies which procedure the obstacle belongs to? If not, is there a publicly available data file that contains all of the 8260 obstacles?
• Where/what is the DVOF?

Digital Data Team

• Does a structure's AGL (height Above Ground Level) include anything on top of that structure?
• What is the difference between the Weekly Construction Notice and the Daily DOF Change File?
• Do Added files always refer to new construction?
• Power lines are categorized as Catenaries and the data for these objects contains a single coordinate. How should we figure out the path of the power lines based on that data?
• Why is the Daily Change File (zipped or unzipped) blank on Monday mornings?
• Do you have data for Restricted Operating Zones (ROZs)?
• Do you have a catalog or other distribution list of Sectional Charts?
• Is it possible to obtain your data as an Excel or .csv file?
• Why don't you remove a structure from your database when the OE/AAA case has been terminated?
• Why is this structure listed in your database when it was dismantled ten years ago?
• Are Dismantled and Removed obstacles removed from the 56-day DOF or the Daily DOF?
• Why does the Quantity field sometimes show a number larger than "1" (more than one obstacle)? Does this mean the file includes multiple points?
• When during the construction process is a structure added to the DOF?
• Where would I find standard FAA obstruction symbols?
• Does the JDATE in the DOF reference the number of elapsed days since the beginning of the 4-digit year (ex. 2012145 = 145th day since the start of the 2012 year)?
• Can you advise your customers of important changes by email?

Digital Products

What digital (electronic format) products does Aeronautical Information Services make available?

• Terminal Procedures and Airport Diagrams
• Chart Supplements
• Coded Instrument Flight Procedures
• VFR Charts
• VFR Class B Graphics
• IFR Charts
• MVA and MIA Charts
• Chart Users' Guide
• Digital Obstacle File
• Daily Digital Obstacle File
• Obstacle Construction Notices
• NASR Subscriber Files
• National Flight Data Digest (NFDD)

Access the Aeronautical Information Services homepage to stay abreast of new aeronautical products and services as they become available.

How can I get a copy of an electronic chart?

FAA electronic files are posted to Digital Products for free download and/or printing as needed.

Can the FAA's digital products be used in private industry software products?
What are the copyright/licensing regulations for these products?

All digital products published by the FAA are in the public domain and are not copyright protected. Therefore, a written release or credit is not required to incorporate them into your own digital products. The FAA cannot endorse or recommend one private industry product over another. Also, since all of our products are date sensitive we recommend that you seek legal advice prior to marketing your own products. To protect the integrity of our aeronautical products, all notations and symbology in the original products are to be included in any tailored versions.

Can I use the CIFP [Coded Instrument Flight Procedures] to update my GPS or FMS?

The CIFP (Coded Instrument Flight Procedures) uses the ARINC 424 standard. GPS and FMS do not currently support the use of "raw" ARINC 424 data. Individual avionics manufacturers process the data into their proprietary format for use in GPS or FMS units. The FAA does not process aeronautical information for use in any GPS or FMS.

Why can't I get your digital files sooner than 20 days prior to their effective dates?

20 days prior availability is a general term. FAA's digital files are posted as soon as practically possible. The information cut-off for the next cycle is 30 days prior to the effective date. That gives us about 10 days, including weekends and holidays, to compile all of the data and get the files posted by the 20th day prior. We strive each cycle to release these products quickly, on or about 20 days prior. Please see list below:

• Digital Terminal Procedures - available 19 days prior
• Digital Chart Supplements - available 21 days prior
• Digital Visual Charts - available 21 days prior
• Digital IFR Charts - available 19 days prior
• Coded Instrument Flight Procedures - available 21 days prior
• Digital Enroute Caribbean Charts - available 14 days prior

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Visual Charts

Why is there a difference between the magnetic variation for the airport and the VOR located at the same airport?

When a navaid is first constructed, the antenna is physically oriented to True North. Then a potentiometer adjustment is made to slave the navaid with Magnetic North. This action matches the isogonic line making it agree with a magnetic compass. Initially these two values are the same, but the magnetic variation of the earth changes at differing rates depending upon location and time.

Navigational aids go into service and remain online 24 hours a day, 365 days a year. The FAA performs periodic maintenance; however, readjustments to match the isogonic value require a total shut down of the equipment, plus recertification and flight check verification. This process begins when a navigational aid is out of tolerance by at least +/-6 degrees. GPS databases use a MAGVAR model to calculate the most up-to-date magnetic variation.

What is the significance of a runway 8069 feet in length and why are two different aerodrome symbols used to depict hard surface runways on Sectional charts?

For purposes of airport depiction, specialists represent a runway between 7970 and 8069 feet in length as 8000 feet, which equates to a line 0.192 inches in length on the Sectional chart scale. In this case, a circular aerodrome symbol is used.

If a runway is between 8070 and 8169 feet in length, specialists round to 8100 feet, which equates to a line 0.1944 inches in length on the sectional chart scale. This line is too long to fit into the largest circular aerodrome symbol FAA has available. Therefore, specialists place a line-work around the runway pattern forming a polygon (enclosed shape) for anything over 8069 feet in length.

Specialists also place these polygons around the runway pattern of aerodromes with multiple runways that are less than 8069 feet, in cases where the multiple runway pattern does not fit into the largest, circular aerodrome symbol.

What is the meaning of RP and *RP on VFR Charts?

RP is the abbreviation for "right pattern" followed by the appropriate runway number(s) and indicates a right traffic pattern.

*RP indicates that there are special conditions or restrictions for right traffic and the pilot should consult the Chart Supplement for those special instructions and/or restrictions. *RP does not indicate that there is right patterned traffic for all aircraft at all times.

What does "OBJECTIONABLE" stand for on VFR Charts?

The type "OBJECTIONABLE" associated with an airport symbol indicates that an objectionable airspace determination has been made for the airport per FAA Order JO 7400.2 Section 4, Airport Charting and Publication of Airport Data. Objectionable airspace determinations can be based upon a number of factors including conflicting traffic patterns with another airport, hazardous runway conditions, or natural or man-made obstacles in close proximity to the landing area. FAA Regional Airports Offices are responsible for airspace determinations. Address any challenges to objectionable airspace determinations to your FAA Regional Airports Office.

How do I add a public or private airport to a chart? (One with a FAA Location Identifier)

VFR charts depict airport's hard and soft surface runways. Enroute charts depict airports having hard surface runways of at least 3000-foot in length. If your airport meets those criteria, you may contact the local Federal Aviation Administration, Airports District Office or Aeronautical Information Management, AJV-21, at 1-(866) 295-8236 to have your airport charted.

The FAA Specialist will verify your airport's information and publish a change in the National Flight Data Digest. This change will generate a charting directive to depict your airport on the chart. The FAA will chart your airport as long as it does not cause chart clutter and does not interfere with any existing data that may have a higher safety priority. The FAA makes every effort to adjust chart data to accommodate your airport name and symbol on the chart for the next publication cycle.

How do I register a private use airport to obtain a location identifier or make changes to an existing private use airport?

To register a private use airport with FAA or make changes to an existing private use airport, please complete and submit FAA FAA Form 7480-1 (INFORMATION/DOCUMENTID/185334) to your local Regional Office per instructions found on the form or submit your information electronically via the OE/AAA system. Once you have begun the registration process, you may contact the same office for the status of your application. To make changes to an existing private use airport, please contact the Regional Office listed on the Form for further assistance.

How can I change the information for a Public Use or Military Airport?

Visit the Aeronautical Data Portal. This information can be found on the inside front cover of the Chart Supplements and shown here. To recommend revisions access (Submit airport data change form.) or write to:

How can I get a parachute jumping symbol for a specific area put on a chart?

Parachute-jumping symbols designate airspace areas to alert the flying public of special air traffic activity. Charting these areas may be accomplished by contacting the FAA Air Traffic Facility (Control Tower, Approach Control Facility, Air Route Traffic Control Center (ARTCC)) having jurisdiction over the airspace and requesting the specific area be charted. The FAA specialist will submit a Special Activity Area Data Sheet to the National Flight Data Center (NFDC) at FAA Headquarters for publication in the National Flight Data Digest. For depiction on a chart, the parachute jumping area must:

• Be in operation for at least 1 year.
• Conduct (and log) 1,000 or more jumps each year.

FAA Regions can nominate jump sites if special circumstances require charting.

Once published in the National Flight Data Digest, FAA Aeronautical Information Services adds the PARACHUTE JUMPING AREA to that section of the Chart Supplement. If it meets minimum charting requirements, the FAA Aeronautical Information Services depicts the appropriate charts with the Parachute Jump Area symbol in the next publication cycle.

How can I get a glider symbol for a specific area put on a chart?

Charting these areas is accomplished by adding an associated remark to the airport record (Example: "Glider activity in vicinity of airport"). Airport owners/managers should access the National Flight Data Center (NFDC) Portal at nfdc.faa.gov and submit an Airport Data Change Form (public and military airports only) or contact Aeronautical Information Management, AJV-21, at 1-(866) 295-8236 and request the addition of the remark. The FAA specialist will verify your information and publish a change in the National Flight Data Digest (NFDD). Once the change is in the NFDD the appropriate publication and charts are updated with the information for the next effective date.

How can I add or make a change to the UNICOM or Common Traffic Advisory Frequency (CTAF) for an airport?

To add, modify or delete UNICOM or Common Traffic Advisory frequencies, airport owners/managers should access the Aeronautical Data Portal and submit an Airport Data Change Form (public and military airports only) or contact Aeronautical Information Management, at 1-(866) 295-8236 and request your authorized UNICOM or CTAF be published and/or charted. The FAA Specialist will verify your information and publish a change in the National Flight Data Digest (NFDD). Once published in the NFDD, the appropriate publications and charts will reflect the new information by the next effective date.

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Chart Supplements (formerly the Airport / Facility Directory)

How can I update my airport diagram information?

Any graphic changes should be submitted using the Aeronautical Chart Change Form found within the Aeronautical Data Portal to submit your requested graphic changes.

How can I make a change to the Chart Supplements?

Requests to make changes to the Chart Supplements should be submitted via our Web Portal: Aeronautical Inquiries

If any clarification or further information is required a specialist will contact you. As soon as the National Aeronautical Data Team has entered your requested change/changes into their database, notice will be directed to everyone producing relevant aviation publications requiring all to amend their products.

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Instrument Flight Procedures

What is an instrument flight procedure?

An instrument flight procedure is a series of predetermined maneuvers for aircraft operating under instrument flight rules, i.e. IFR conditions, when visual flight is not possible due to weather or other visually restrictive conditions. These maneuvers allow for the orderly transition of the aircraft through a particular airspace. The term "instrument flight procedure" refers to instrument approaches, instrument departures, and instrument enroute operations.

IFR approach procedures are developed and approved for a specific airport. These procedures are critical to flight safety and safe operations during periods of marginal weather/visibility and in areas of adverse terrain.

Instrument approach procedures also allow for the transition from enroute operations to the terminal area for landing at the destination airport. The instrument approach procedure uses ground or satellite based systems to provide guidance and obstruction clearance to the runway or to an altitude from which visual operations for landing can begin.

Departure procedures allow for orderly movement along a specified route providing obstruction clearances from the point of departure to a position at which EnRoute operations can begin.

How does FAA develop an instrument flight procedure?

The specialist uses terrain, and man-made obstruction data in the development of the airport procedure. The specialist also considers any special design needs requested by the applicable country that meet the specified criteria. Each segment of the procedure is designed and documented.

What data will be required for FAA to produce these Instrument Procedure Charts?

The charting of instrument flight procedure is restricted to those that have been Quality Controlled by the FAA. In order to complete these charts, accurate data is required in English, by the requesting country. These may include airport, obstacle, communication, fix, special use and terrain data.

What shall I expect after the instrument flight procedure is developed?

Once a designed instrument flight procedure passes the quality review process, it is certified through an actual flight inspection, and then it's charted and published for use.

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Chart Discrepancies

How can I report chart discrepancies?

You are encouraged to bring charting errors to our attention. Every FAA Aeronautical product contains contact information and brief instructions for reporting charting errors. You may contact us via our Web Portal: Aeronautical Inquiries or by calling 800-638-8972 (toll free, U.S. only).

Where can I review product errors and see product enhancements?

You can find out about product errors and updates by going to the Safety Alerts/Charting Notices page. Also consider subscribing to this page by clicking the Subscribe Icon located above the Top Tasks box. This will allow us to send you an email notification when anything is added to this page.

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Chart Users' Guide

What is the Aeronautical Chart Users' Guide?

FAA Aeronautical Chart Users' Guide is designed to be used as a teaching aid, reference document, and an introduction to the wealth of information provided on FAA's aeronautical charts and publications. It includes explanations of aeronautical chart terms and symbols, plus a visual depiction of all of the symbols organized by chart type.

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Navigation

Why should I fly with current charts?

FAR 91.103 Preflight action

Before beginning a flight, each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight.

FAA charts and related products are continually updated to reflect current aeronautical, terrain and cultural information. The following table shows the average number of changes per product type per cycle:

What is the FAA policy for carrying current charts?

The specific FAA regulation, FAR 91.103 "Preflight Actions," states that each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight. Although the regulation does not specifically require it, you should always carry a current chart with you in flight. Expired charts may not show frequency changes or newly constructed obstructions, both of which when unknown could be a hazard.

The only FAA/FAR requirements that pertain to charts are:

• Title 14 CFR section 91.503[a] (Large and Turbojet powered aircraft)
• Title 14 CFR section 135.83 (Air Carriers-Little Airplane)
• Title 14 CFR section 121.549 (Air Carrier-Big Airplanes)

The FAA's July/August 1997 issue of FAA Aviation News on "current" aeronautical charts provided the following information:

1. "You can carry old charts in your aircraft." "It is not FAA policy to violate anyone for having outdated charts in the aircraft."
2. "Not all pilots are required to carry a chart." "91.503..requires the pilot in command of large and multiengine airplanes to have charts." "Other operating sections of the FAR such as Part 121 and Part 135 operations have similar requirements."
3. ..."since some pilots thought they could be violated for having outdated or no charts on board during a flight, we need to clarify an important issue. As we have said, it is NOT FAA policy to initiate enforcement action against a pilot for having an old chart on board or no chart on board." That's because there is no regulation on the issue.
4. ..."the issue of current chart data bases in handheld GPS receivers is a non-issue because the units are neither approved by the FAA or required for flight, nor do panel-mounted VFR-only GPS receivers have to have a current data base because, like handheld GPS receivers, the pilot is responsible for pilotage under VFR.
5. "If a pilot is involved in an enforcement investigation and there is evidence that the use of an out-of-date chart, no chart, or an out-of-date database contributed to the condition that brought on the enforcement investigation, then that information could be used in any enforcement action that might be taken."

What is the database currency requirement needed for VFR or IFR flight?

AIM 1-1-19b3(b) Database Currency (1) In many receivers, an up-datable database is used for navigation fixes, airports and instrument procedures. These databases must be maintained to the current update for IFR operations, but no such requirement exists for VFR use. (2) However,...

AIM 1-1-19f1(b) Equipment and Database Requirements - For IFR Operations "All approach procedures to be flown must be retrievable from the current airborne navigation database..."

AC 90-100, U.S. TERMINAL AND EN ROUTE AREA NAVIGATION (RNAV) OPERATIONS, paragraph 8a(3): The onboard navigation data must be current and appropriate for the region of intended operation and must include the navigation aids, waypoints, and relevant coded terminal airspace procedures for the departure, arrival, and alternate airfields.

Navigation databases are expected to be current for the duration of the flight. If the AIRAC cycle will change during flight, operators and pilots should establish procedures to ensure the accuracy of navigation data, including suitability of navigation facilities used to define the routes and procedures for flight. Traditionally, this has been accomplished by verifying electronic data against paper products. One acceptable means is to compare aeronautical charts (new and old) to verify navigation fixes prior to dispatch. If an amended chart is published for the procedure, the database must not be used to conduct the operation."

Published instrument procedures and routes are incorporated by reference into 14 CFR Part 95 and 14 CFR Part 97, are "law." They are "effective" only during the AIRAC cycle dates specified on the enroute chart/TPP covers or on the side of the chart when printed from the digital-TPP. If you are using a published procedure before or after the dates specified on the chart under IFR, you are technically in violation of the law.

What is the process for establishing Rulemaking (i.e. Class A, B, C, etc., Restricted, etc.) and Nonrulemaking (i.e. Military Operations, Warning, Alert, etc.) Airspace areas on aeronautical charts?

The FAA cannot arbitrarily depict airspace on its charts without proper authorization. Certain procedures must be followed before the FAA may chart any aeronautical information, especially airspace. Please consult FAA Order, JO 7400.2 - Procedures for Handling Airspace Matters for information about the process for establishing rulemaking and nonrulemaking airspace.

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Digital Obstacle File (DOF)

Is the DOF data considered to be in the public domain? Are there any restrictions on using the DOF data?

Yes, it is in the public domain. There are no restrictions on how you may use the data, but you are not allowed to change the data.

In the DOF, how does one differentiate between a dismantled structure and an existing structure at the same location?

In our Digital Obstacle File (DOF), the letter in the "Verified Status" column shows whether a structure is Unverified (U) or Verified (V). The letter in the "Action" column shows the last action performed on the file, which can be Added (A), Changed (C), or Dismantled (D).

Why does the City Name field sometimes show "CITY, STATE" instead of the normal "CITY"?

The obstacle may be in one state, but the nearest associated city might be across the border in another state. The DOF was originally created for internal use by our Visual Charting team, and the nearest associated city/state name helps them locate the area on the chart to plot the obstacle. It also gives our users a quick reference as to its location.

Users should be aware that the DOF contains more than 6,000 records with a comma ("CITY, STATE") in the City Name field. Using this format has been a part of our standard operating procedures since the 1970's.

In your database, is there a field that specifies whether obstructions are single or group?

Yes. Currently, the "OBSTACLE TYPE" column includes the number of structures in that file, to the right of the actual structure type.

Do you have shape files for your DOF data?

None of our products include shape files for DOF data.

Do you have more specific metadata for your obstacles? (i.e. Is a "sign" a traffic sign, a billboard, etc?)

We do not differentiate the various obstacle types. What you see in the DOF is as specific as we get.

Do you have more specific metadata for your "TREE" and "VEGETATION" obstacles?

We only differentiate between trees and other vegetation.

Your database does not seem to contain many buildings that exist in a particular area. Does the DOF not include all tall structures?

This office is tasked to maintain data on all structures over 200 feet above ground level and lower structures affecting F.A.R. Part 77 in the vicinity of airports with approach procedures. Maintaining an accurate, updated database depends entirely upon structures being reported to us in timely fashion by several sources, mainly the FAA's OE/AAA group, but also NOAA, FCC, NGA and other federal agencies. When tall structures are built and not reported to this office, this could have a negative effect on air navigation and would be of concern to us.

If you have not found certain existing structures in the online DOF, you should go to the following, and check the various search options on the left side of the page: Obstruction Evaluation / Airport Airspace Analysis (OE/AAA)

Note, many of the structures listed with the OE/AAA are in proposal or construction stage, and thus would not be listed in the DOF. However, there may be time lag between completion of a project and reporting to this office. Please do inform us of any structures that have been constructed and that you believe are over 200 feet above ground level height that are not listed in the DOF. You would need to provide us with an exact location with coordinates (GPS, Google Earth, other documentation) and any other information you might have (exact or approximate heights, current owner, etc.). We will have our analysts investigate to make sure all structures affecting navigable airspace are properly accounted for.

Does the DOF contain obstacles for approach procedures (found on the FAA form 8260)? If so, is there attribution that identifies which procedure the obstacle belongs to? If not, is there a publicly available data file that contains all of the 8260 obstacles?

The obstacles (manmade) for approach procedures are in the DOF database, but the attribution for the procedure is not part of the existing file. You would have to do a DOF search of the airport coordinates to obtain the listing of potential obstacles.

Where/what is the DVOF?

DVOF (Digital Vertical Obstruction File) is a Dept of Defense/NGA product not distributed through the FAA Obstacle Data Team website. Please visit the National Geospatial-Intelligence Agency.

If you have a question that you do not see here, please see Aeronautical Inquiries.

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Does a structure's AGL (height Above Ground Level) include anything on top of that structure?

Yes. Always include the tallest structure/appurtenance (i.e. antenna, light, lightning rod for towers; penthouse, helipad, flagpole, electrical/air conditioning equipment, etc. for buildings) on top of a structure when determining the AGL.

What is the difference between the Weekly Construction Notice and the Daily DOF Change File?

The Weekly Construction Notices and the Daily DOF Change Files do show the same change information for the 56-day DOF and the Daily DOF respectively, but they are in different formats and on different schedules because they are used by different users.

Do Added files always refer to new construction?

Not always. Added files could be either newly constructed obstacles or existing obstacles that were not previously in our database.

Power lines are categorized as Catenaries and the data for these objects contains a single coordinate. How should we figure out the path of the power lines based on that data?

The catenary is the highest point in the sag above ground between transmission towers. No directional data is included. You would have to identify the related transmission towers in the Digital Obstacle File (DOF) to determine the direction. You could also check the related Sectional Aeronautical Chart to see if the transmission lines are plotted.

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Products - Digital and Physical Products

Why is the Daily Change File (zipped or unzipped) blank on Monday mornings?

The Daily Change File is blank on Monday mornings because there are no changes to the DOF on weekends or holidays. We are currently working on adding a message to the file to explain this, which we hope will help avoid confusion/frustration.

Do you have data for Restricted Operating Zones (ROZs)?

We do not maintain ROZ data.

Do you have a catalog or other distribution list of Sectional Charts?

For information on Sectional Charts and other FAA products, please review the items in the Aeronautical Information Services Products Catalog.

Is it possible to obtain your data as an Excel or .csv file?

No, it is only available as a text file at this time.

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Obstacles - How We Do Our Job

Why don't you remove a structure from your database when the OE/AAA case has been terminated?

When an OE/AAA case is terminated, the associated structure is not necessarily dismantled. A termination means that a planned project/scenario (i.e. height change, frequency change, new construction, dismantlement, etc.) has been cancelled.

Why is this structure listed in your database when it was dismantled ten years ago?

Dismantled structures (denoted as "D" in our database) are kept as historical records. However, if a dismantled structure was not reported, it remains as "Constructed" (or "C") in our database.

Are Dismantled and Removed obstacles removed from the 56-day DOF or the Daily DOF?

Both of these statuses are included on the 56-day Change File (CHG.dat) and the Daily DOF Change Files. "Dismantled" files are kept in the DOF and the DDOF for historical purposes, while "Removed" files are removed from both.

Why does the Quantity field sometimes show a number larger than "1" (more than one obstacle)? Does this mean the file includes multiple points?

The number in that column is normally "1" unless there are obstacles grouped very close together. In the past, they were treated as "arrays" and there could be anywhere from 2-9 obstacles in an array. The coordinates for an array were the center point of the grouped obstacles. We no longer enter obstacles as "arrays," but there are still some in the database. As we evaluate these, we will break them up into individual obstacles with their own Lat/Long, AGL and AMSL. We only put "single point" features in our database. At this time, we don't have the capability to input linear features or polygons.

When during the construction process is a structure added to the DOF?

When the aeronautical study is received from the Obstacle Evaluation Group as a new structure Under Construction or Completed to its greatest height, our analysts will verify the data. Upon verification the case will be assigned a file number (ORS identifier), forwarded to a Quality Control Specialist for review, and entered in to the ORS/DOF database. The DOF is refreshed every day at 11:46pm for all approved data files that were entered for that day.

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Resources

Where would I find standard FAA obstruction symbols?

All of FAA's obstruction symbol explanations are in the Aeronautical Chart Users' Guide, which is available as a large (23 MB) downloadable PDF file.

Does the JDATE in the DOF reference the number of elapsed days since the beginning of the 4-digit year (ex. 2012145 = 145th day since the start of the 2012 year)?

Yes. To convert to and from Jdates, try this Julian Date Calculator.

Can you advise your customers of important changes by email?

For any significant changes, please subscribe to the Safety Alerts and Charting Notices webpage.

If you have specific questions, please see Aeronautical Inquiries.

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