INSTRUMENT FLIGHT RULES WORKBOOK
205. ENROUTE LOW ALTITUDE CHARTS
These charts portray the airway system and related data required for IFR operations at altitudes
below 18,000 feet MSL. Twenty-six variable scale charts are printed on thirteen sheets, L-1
through L-26, covering the entire United States. An additional sheet, charts L-27 and L-28
duplicating data shown on L-20, L-22, L-24, and L-25, is available for those who frequently plan
flights north and south along the East Coast within the area of coverage. Charts covering the
area of flight must be carried in the aircraft for all IFR flights. See bottom of front page on the
L-18/L-17 chart for portrayals.
The effective date and the expiration date are shown on the cover of each chart. Major changes
to the airway structure and procedures are scheduled by the FAA to become effective on a
specific date once every eight weeks. Charts are revised accordingly and show the date this
information is effective. Charts, therefore, should not be used prior to the "effective date."---
other information; i.e., frequencies, hours of operation, etc., are not scheduled and changes occur
daily. Action is taken to update this data during the revision cycle, but it has to be terminated
fifteen days before the projected "effective date" of the issue under revision to permit printing
and timely distribution to users. NOTAMs must be consulted for latest information on data
changing after the "cutoff date" and during the life of the current charts.
206. AREA CHARTS
These charts portray the airway system and related data required for IFR operations in selected
terminal areas at altitudes below 18,000 feet MSL. Twelve variable scale charts are printed on
one sheet. Since area charts include terminal NAVAID and airport information which may not
be contained in the enroute charts, area charts must be consulted when conducting terminal
flight operations within the areas covered. (View A-1\A-2 IFR Area Chart).
IMPORTANT FACTS AND DEFINITIONS NOT FOUND IN THE LEGEND ON LOW
ALTITUDE OR AREA CHARTS
1. ATIS: Automatic Terminal Information Service. Pilots are expected to listen to ATIS
broadcasts where in operation to obtain essential, but routine, terminal information. ATIS
broadcasts are recorded and the pilot should notify controllers that he has received the broadcast
by repeating the alphabetical code word appended to the broadcast. Example: "Information Echo
received." Controllers will automatically issue pertinent information to pilots who do not
acknowledge receipt of the ATIS broadcast or who acknowledge receipt of a broadcast that is not
2. COMPASS LOCATOR BEACON (Locator Outer Marker (LOM)): A Non-
directional Radio Beacon used in conjunction with an instrument landing system. Check the
legend for the appropriate symbol.
3. ILS: Instrument Landing System: Provides azimuth and glideslope information on the
Course Indicator. It is a type of precision approach. (T-34 not equipped to receive glideslope
information.) Check the legend for the appropriate symbol.
2-22 IFR SUPPLEMENT, FLIGHT INFORMATION HANDBOOK, ENROUTE LOW
ALTITUDE CHARTS, GENERAL PLANNING, AND AREA PLANNING