Searchable explanations of IFR enroute airports, radio aids, airspace, airways, foreign areas, and terrain contours.
Route segments with a width of 5 NM or less, both sides of the centerline, are shown by a.02" line.
MTR ≤5 NM each side — IR000 thin line — source page 71.
Route segments with a width greater than 5 NM, either or both sides of the centerline, are shown by a.035" line.
MTR >5 NM either/both sides — VR000 thick line — source page 71.
MTRs for particular chart pairs (ex. L1/2, etc.) are alphabetically, then numerically tabulated. The tabulation includes MTR type and unique identification and altitude range.
Coincident Airways/Routes with Unusable Segment When two airways/routes are coincident, but only one airway/route is designated as unusable, the following note indicating which airway the unusable symbology applies to will be placed in close proximity to the airway/route identifiers. OFF ROUTE OBSTRUCTION CLEARANCE ALTITUDE (OROCA) The Off Route Obstruction Clearance Altitude (OROCA) is depicted on IFR Enroute Low Altitude and Pacific charts and is represented in thousands and hundreds of feet above MSL. OROCAs are shown in every 30 x 30 minute quadrant on Area Charts, every one degree by one degree quadrant for IFR Enroute Low Altitude Charts - U.S. and every two de¬gree by two degree quadrant on IFR Enroute Low Altitude Charts - Alaska. The OROCA is based on the highest known terrain feature or obstruction in each quadrangle, bounded by the ticked lines of latitude/longitude including data 4 NM outside the quadrant. In this example the OROCA represents 12,500 feet. OROCA is computed just as the Maximum Elevation Figure (MEF) found on Visual Flight Rule (VFR) Charts except that it provides an additional vertical buffer of 1,000 feet in designated non-mountainous areas and a 2,000 foot vertical buffer in designated mountainous areas within the United States. Evaluating the area around the quadrant provides the chart user the same lateral clearance an airway provides should the line of intended flight follow a ticked line of latitude or longitude. OROCA altitudes are not assessed for NAVAID signal coverage, air traffic control surveillance, or communications coverage, and are published for general situational awareness, flight planning, and in-flight contingency use. OROCAs can be found over all land masses and open water areas containing man-made obstructions (such as oil rigs). MILITARY TRAINING ROUTES (MTRs) Military Training Routes (MTRs) are routes established for the conduct of low-altitude, high-speed military flight training (generally below 10,000 feet MSL at airspeeds in excess of 250 knots Indicated Air Speed). These routes are depicted in brown on IFR Enroute Low Altitude Charts, and are not shown on inset charts or on IFR Enroute High Altitude Charts. IFR Enroute Low Altitude Charts depict all IFR Military Training Routes (IRs) and VFR Military Training Routes (VRs), except those VRs that are entirely at or below 1,500 feet AGL. MTRs are identified by designators (IR-107, VR-134) that are shown in brown on the route centerline. Arrows are shown to indicate the direction of flight along the route. The width of the route determines the width of the line that is plotted on the chart: Route segments with a width of 5 NM or less, both sides of the centerline, are shown by a.02" line. Route segments with a width greater than 5 NM, either or both sides of the centerline, are shown by a.035" line. MTRs for particular chart pairs (ex. L1/2, etc.) are alphabetically, then numerically tabulated. The tabulation includes MTR type and unique identification and altitude range.
Source page 72
ALASKA CAPSTONE ROUTES (R Routes)
The Alaska Capstone program is an initiative to enhance safety and improve the efficient use of the navigable airspace in Alaska. R Routes are low altitude RNAV Routes that require specific FAA authorization. The routes are published on the L-1 Alaska Low Altitude Enroute Chart. The R Routes and associated notes are published in green with a “R” identifier followed by the route number, followed by a negative “R” identifier. An associated boxed note, also in green, is shown in close proximity to the routes.
Alaska Capstone R Route R2015R with RNP-1 note — source page 72.
JET ROUTE SYSTEM (HIGH ALTITUDE ENROUTE CHARTS)
Jet routes are based on VOR or VORTAC NAVAIDs, and are depicted in black with a "J" identifier followed by the route number (e.g., "J12"). In Alaska, Russia and Canada some segments of jet routes are based on LF/MF NAVAIDs.
AREA NAVIGATION (RNAV) "Q" ROUTE SYSTEM (IFR ENROUTE HIGH ALTITUDE CHARTS)
The FAA has adopted certain amendments to Title 14, Code of Federal Regulations, which paved the way for the development of new area high altitude navigation (RNAV) "Q" routes in the U.S. National Airspace System (NAS). These amendments enable the FAA to take advantage of technological advancements in navigation systems such as the GPS. RNAV "Q" Route MEAs are shown when other than FL 180 MEAs for DME/DME/Inertial Reference Unit (IRU) RNAV aircraft have a "D" suffix.
High-enroute RNAV Q9 — MEA-29000D, magnetic-reference bearings, waypoint — source page 72.
Joint Jet/RNAV route identification boxes will be located adjacent to each other with the route charted in black. With the exception of Q-Routes in the Gulf of Mexico, GNSS or DME/DME/IRU RNAV are required, unless otherwise indicated. Q-Routes in Alaska are GNSS Only. Altitude values are stacked highest to lowest.
Joint Jet/RNAV route J45/Q19 — source page 72.
ALASKA CAPSTONE ROUTES (R Routes) The Alaska Capstone program is an initiative to enhance safety and improve the efficient use of the navigable airspace in Alaska. R Routes are low altitude RNAV Routes that require specific FAA authorization. The routes are published on the L-1 Alaska Low Altitude Enroute Chart. The R Routes and associated notes are published in green with a “R” identifier followed by the route number, followed by a negative “R” identifier. An associated boxed note, also in green, is shown in close proximity to the routes. JET ROUTE SYSTEM (HIGH ALTITUDE ENROUTE CHARTS) Jet routes are based on VOR or VORTAC NAVAIDs, and are depicted in black with a "J" identifier followed by the route number (e.g., "J12"). In Alaska, Russia and Canada some segments of jet routes are based on LF/MF NAVAIDs. AREA NAVIGATION (RNAV) "Q" ROUTE SYSTEM (IFR ENROUTE HIGH ALTITUDE CHARTS) The FAA has adopted certain amendments to Title 14, Code of Federal Regulations, which paved the way for the development of new area high altitude navigation (RNAV) "Q" routes in the U.S. National Airspace System (NAS). These amendments enable the FAA to take advantage of technological advancements in navigation systems such as the GPS. RNAV "Q" Route MEAs are shown when other than FL 180 MEAs for DME/DME/Inertial Reference Unit (IRU) RNAV aircraft have a "D" suffix. RNAV routes and associated data are charted in blue."Q" Routes on the IFR Gulf of Mexico charts are shown in black. Magnetic reference courses are shown originating from a waypoint, fix/reporting point, or NAVAID. Joint Jet/RNAV route identification boxes will be located adjacent to each other with the route charted in black. With the exception of Q-Routes in the Gulf of Mexico, GNSS or DME/DME/IRU RNAV are required, unless otherwise indicated. Q- Routes in Alaska are GNSS Only. Altitude values are stacked highest to lowest. Joint Jet/RNAV Route
Source page 73
FOREIGN AREAS
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