Uncontrolled and Tower-Controlled Airports
Visual Approach Slope Indicator (VASI)
Airport Traffic Area Communications and Light Signals
Communication Phraseology, Techniques, and Procedures
Radar Assistance to VFR Aircraft
Controlled airspace, that is, airspace within which some or all aircraft may be subject to air traffic control, consists of those areas designated as Class A, Class B, Class C, Class D, and Class E airspace.
Much of the controlled airspace begins at either 700 feet or 1,200 feet above the ground. The lateral limits and floors of Class E airspace of 700 feet are defined by a magenta vignette; while the lateral limits and floors of 1,200 feet are defined by a blue vignette if it abuts uncontrolled airspace. Floors other than 700 feet or 1,200 feet are indicated by a number indicating the floor.

Figure 6-1
Class A—Class A airspace extends from 18,000 feet MSL up to and including FL600 and is not depicted on VFR sectional charts. No flight under visual flight rules (VFR), including VFR-on-top, is authorized in Class A airspace.
Class B—Class B airspace consists of controlled airspace extending upward from the surface or higher to specified altitudes. Each Class B airspace sector, outlined in blue on the sectional aeronautical chart, is labeled with its delimiting altitudes. On the Terminal Area Chart, each Class B airspace sector is, again, outlined in blue and is labeled with its delimiting arcs, radials, and altitudes. Each Class B airspace location will contain at least one primary airport. An ATC clearance is required prior to operating within Class B airspace. A pilot landing or taking off from one of a group of twelve specific, busy airports must hold at least a Private Pilot Certificate. At other airports, a student pilot may not operate an aircraft on a solo flight within Class B airspace or to, from, or at an airport located within Class B airspace unless both ground and flight instruction has been received from an authorized instructor to operate within that Class B airspace or at that airport, and the flight and ground instruction has been received within that Class B airspace or at the specific airport for which the solo flight is authorized. The student’s logbook must be endorsed within the preceding 90 days by the instructor who gave the flight training and the endorsement must specify that the student has been found competent to conduct solo flight operations in that Class B airspace or at that specific airport. Each airplane operating within Class B airspace must be equipped with a two-way radio with appropriate ATC frequencies, and a 4096 code transponder with Mode C automatic altitude-reporting capability.
Class C—All Class C airspace has the same dimensions with minor site variations. They are composed of two circles both centered on the primary airport. The inner circle (now called surface area) has a radius of 5 NM and extends from the surface up to 4,000 feet above the airport. The outer circle (now called shelf area) has a radius of 10 nautical miles and extends vertically from 1,200 feet AGL up to 4,000 feet above the primary airport. In addition to the Class C airspace proper, there is an outer area with a radius of 20 NM and vertical coverage from the lower limits of the radio/radar coverage up to the top of the approach control facility’s delegated airspace. Within the outer area, pilots are encouraged to participate but it is not a VFR requirement. Class C airspace service to aircraft proceeding to a satellite airport will be terminated at a sufficient distance to allow time to change to the appropriate tower or advisory frequency. Aircraft departing satellite airports within Class C airspace shall establish two-way communication with ATC as soon as practicable after takeoff. On aeronautical charts, Class C airspace is depicted by solid magenta lines.
Class D—Class D airspace extends upward from the surface to approximately 2,500 feet AGL (the actual height is as needed). Class D airspace may include one or more airports and is normally 4 NM in radius. The actual size and shape is depicted by a blue dashed line and numbers showing the top. When the ceiling of Class D airspace is less than 1,000 feet and/or the visibility is less than 3 SM, pilots wishing to take off or land must hold an instrument rating, must have filed an instrument flight plan, and must have received an appropriate clearance from ATC. In addition, the aircraft must be equipped for instrument flight. At some locations, a pilot who does not hold an instrument rating may be authorized to take off or land when the weather is less than that required for visual flight rules. When special VFR flight is prohibited, it will be depicted by “No SVFR” above the airport information on the chart.
Class E—Magenta shading identifies Class E airspace starting at 700 feet AGL, and no shading (or blue if next to Class G airspace) identifies Class E airspace starting at 1,200 feet AGL. It may also start at other altitudes. All airspace from 14,500 feet to 17,999 feet and airspace above 60,000 feet is Class E airspace. It also includes the surface area of some airports with an instrument approach but no control tower.
An airway is a corridor of controlled airspace extending from 1,200 feet above the surface (or as designated) up to and including 17,999 feet MSL, and 4 NM either side of the centerline. The airway is indicated by a centerline, shown in blue.
Class G—Class G airspace is airspace within which ATC has neither the authority nor responsibility to exercise any control over air traffic. Class G airspace typically extends from the surface to the base of the overlying controlled (Class E) airspace which is normally 700 or 1,200 feet AGL. In some areas of the western United States and Alaska, Class G airspace may extend from the surface to 14,500 feet MSL. An exception to this rule occurs when 14,500 feet MSL is lower than 1,500 feet AGL.
Prohibited Areas are blocks of airspace within which the flight of aircraft is prohibited.
Restricted Areas denote the presence of unusual, often invisible, hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. Penetration of Restricted Areas without authorization of the using or controlling agency may be extremely hazardous to the aircraft and its occupants.
Warning Areas contain the same hazardous activities as those found in Restricted Areas, but are located in international airspace. Prohibited, restricted, or warning areas are depicted as shown in FAA Legend 1.
Military Operations Areas (MOAs) consist of airspace established for the purpose of separating certain military training activities from instrument flight rules (IFR) traffic. Pilots operating under VFR should exercise extreme caution while flying within an active MOA. Any FSS within 100 miles of the area will provide information concerning MOA hours of operation. Prior to entering an active MOA, pilots should contact the controlling agency for traffic advisories.
Alert Areas may contain a high volume of pilot training activities or an unusual type of aerial activity, neither of which is hazardous to aircraft. Pilots of participating aircraft as well as pilots transiting the area are equally responsible for collision avoidance.
Aircraft are requested to remain at least 2,000 feet above the surface of National Parks, National Monuments, Wilderness and Primitive Areas, and National Wildlife Refuges.
Military Training Routes (MTRs) have been developed for use by the military for the purpose of conducting low-altitude, high-speed training. Generally, MTRs are established below 10,000 feet MSL for operations at speeds in excess of 250 knots.
IFR Military Training Routes (IR) operations are conducted in accordance with IFR, regardless of weather conditions. VFR Military Training Routes (VR) operations are conducted in accordance with VFR. IR and VR at and below 1,500 feet AGL (with no segment above 1,500) will be identified by four digit numbers, e.g., VR1351, IR1007. IR and VR above and below 1,500 feet AGL (segments of these routes may be below 1,500) will be identified by three digit numbers, e.g., IR341, VR426.
Airport traffic control towers are established to promote the safe, orderly, and expeditious flow of air traffic. The tower controller will issue instructions for aircraft to follow the desired flight path while in the airport traffic area whenever necessary by using terminology as shown in Figure 6-2.

Figure 6-2
The tower controller will also direct aircraft taxiing on the surface movement area of the airport. In all instances, an appropriate clearance must be received from the tower before taking off or landing.
At airports without an operating control tower, pilots of fixed-wing and weight-shift control aircraft must circle the airport to the left (“left traffic”) unless visual indicators indicate right traffic.
A common visual indicator is the segmented circle system, which consists of the following components (see Figure 6-3):

Figure 6-3. Segmented circle and landing direction indicator

Figure 6-4. Wind/landing direction indicators
The tetrahedron, wind cone, wind sock, or wind tee may be located in the center of the segmented circle and may be lit for night operations.
Landing runway (landing strip) indicators are installed in pairs and used to show alignment of runways. See Figure 5-4(a). Traffic pattern indicators are installed in pairs in conjunction with landing strip indicators, and are used to indicate the direction of turns. See Figure 6-5(b).

Figure 6-5. Landing runway and traffic pattern indicators
Approaching to land at an airport without a control tower, or when the control tower is not in operation, the pilot should observe the indicator for the approach end of the runway to be used. VFR landings at night should be made the same as during daytime.
Aircraft departing an uncontrolled airport must comply with any FAA traffic pattern established for that airport.
Runway numbers and letters are determined from the approach direction. The number is the magnetic heading of the runway rounded to the nearest 10°. For example, an azimuth of 183° would result in a runway number of 18; a magnetic azimuth of 076° would result in a runway numbered 8. Runway letters differentiate between left (L), right (R), or center (C). See Figure 6-6.

Figure 6-6. Runway numbers and letters
The designated beginning of the runway that is available and suitable for the landing of aircraft is called the threshold (Figure 6-7a). A threshold that is not at the beginning of the full-strength runway pavement is a displaced threshold. The paved area behind the displaced threshold is marked by arrows (Figure 6-7b) and is available for taxiing, takeoff, and landing rollout, but is not to be used for landing, usually because of an obstruction in the approach path. See Figure 6-7.

Figure 6-7. Threshold marking
Stopways are found extending beyond some usable runways. These areas are marked by chevrons, and while they appear usable, they are suitable only as overrun areas. See Figure 6-8.

Figure 6-8. Stopway marking
A closed runway which is unusable and may be hazardous, even though it may appear usable, will be marked by an “X.”
LAHSO stands for land and hold short operations. These operations include landing and holding short of an intersecting runway, an intersecting taxiway, or some other designated point on a runway other than an intersecting runway or taxiway. LAHSO is an air traffic control procedure that requires pilot participation to balance the needs for increased airport capacity and system efficiency, consistent with safety. Student pilots or pilots not familiar with LAHSO should not participate in the program. The pilot-in-command has the final authority to accept or decline any land and hold short clearance. The safety and operation of the aircraft remain the responsibility of the pilot. Pilots are expected to decline a LAHSO clearance if they determine it will compromise safety. Available landing distance (ALD) data is published in the special notices section of the Chart Supplements U.S. and in the U.S. Terminal Procedures Publications. Pilots should only receive a LAHSO clearance when there is a minimum ceiling of 1,000 feet and 3 statute miles visibility. The intent of having “basic” VFR weather conditions is to allow pilots to maintain visual contact with other aircraft and ground vehicle operations.
Looking at FAA Figure 64 in the Airman Knowledge Testing Supplement:
Looking at FAA Figure 65 in the Airman Knowledge Testing Supplement:
A closed runway which is unusable and may be hazardous, even though it may appear usable, will be marked by an “X.”
At night, the location of an airport can be determined by the presence of an airport rotating beacon light. The colors and color combinations that denote the type of airports are:
|
White and green |
Lighted land airport |
|
Green alone* |
Lighted land airport |
|
White and yellow |
Lighted water airport |
|
Yellow alone* |
Lighted water airport |
|
Green, yellow, white |
Lighted heliport |
*Note: Green alone or yellow alone is used only in connection with a white-and-green or white-and-yellow beacon display, respectively.
A civil lighted land airport beacon will show alternating white and green flashes. A military airfield will be identified by dual-peaked (two quick) white flashes between green flashes.
In Class B, C, D, or E airspace, operation of the airport beacon during the hours of daylight often indicates the ceiling is less than 1,000 feet and/or the visibility is less than 3 miles. However, pilots should not rely solely on the operation of the airport beacon to indicate if weather conditions are IFR or VFR.
Runway edge lights are used to outline the runway at night or during periods of low visibility. For the most part, runway edge lights are white, and may be high-, medium-, or low-intensity, while taxiways are outlined by blue omnidirectional lights.
Radio control of lighting is available at some airports, providing airborne control of lights by keying the aircraft’s microphone. The control system is responsive to 7, 5, or 3 microphone clicks. Keying the microphone seven times within 5 seconds will turn the lighting to its highest intensity; five times in 5 seconds will set the lights to medium intensity; low intensity is set by keying three times in 5 seconds.
The visual approach slope indicator (VASI) is a lighting system arranged so as to provide visual-descent guidance information during approach to a runway. The lights are visible for up to 5 miles during the day. The VASI glide path provides obstruction clearance, while lateral guidance is provided by the runway or runway lights. When operating to an airport with an operating control tower, the pilot of an airplane approaching to land on a runway served by a VASI is required to maintain an altitude at or above the glide slope until a lower altitude is necessary for landing.
Most VASI installations consist of two bars, near and far, which provide one visual glide path. On final approach flying toward the runway of intended landing, if the pilot sees both bars as red, the aircraft is below the glide path (Figure 6-9A). Maintaining altitude, the pilot will see the near bar turn pink and then white, while the far bar remains red, indicating the glide path is being intercepted (Figure 6-9B). If the aircraft is above the glide path, the pilot will see both near and far bars as white (Figure 6-9C).

Figure 6-9. A 2-bar VASI
Pulsating VASIs normally consist of a single light unit projecting a two-color visual approach path. The below-glide-path indication is normally red or pulsating red, and the above-glide-path indication is normally pulsating white. The on-glide-path indication is usually steady white. See Figure 6-10.

Figure 6-10. Pulsating VASI system
The precision approach path indicator (PAPI) uses a single row of lights. Four white lights means “too high.” One red light and three white lights means “slightly high,” etc. See Figure 6-11.

Figure 6-11. Precision approach path indicator (PAPI)
Taxiing to or from the runway generally presents no problems during calm or light wind conditions. However, when taxiing in moderate to strong wind conditions, the airplane’s control surfaces must be used to counteract the effects of wind. In airplanes equipped with a nose wheel (tricycle-gear), use the following taxi procedures:

Figure 6-12. Control position while taxiing
When an airplane equipped with a tailwheel is taxied into a headwind, the elevator should be held in the up position to hold the tail down. In a quartering tailwind, both the upwind aileron and the elevator should be in the down position.
The Chart Supplements U.S. is a publication designed primarily as a pilot’s operational manual containing all airports, seaplane bases, and heliports open to the public including communications data, navigational facilities, and certain special notices and procedures. Directories are reissued in their entirety every 56 days.
Because of the wealth of information provided, an extensive legend is required for the Chart Supplements Airport/Facility section. See FAA Legends 2–19.
Unless otherwise authorized, aircraft are required to maintain two-way radio communication with the ATC towers when operating to, from, or on the controlled airport, regardless of the weather. If radio contact cannot be maintained, ATC will direct traffic by means of light gun signals as shown in Figure 6-13.

Figure 6-13. ATC light gun signals
If the aircraft radios fail while inbound to a tower-controlled airport, the pilot should remain outside or above the airport traffic area until the direction and flow of traffic has been determined and then join the airport traffic pattern and watch the tower for light signals.
The general warning signal (alternating red and green) may be followed by any other signal. For example, while on final approach for landing, an alternating red and green light followed by a flashing red light is received from the control tower. Under these circumstances, the pilot should abandon the approach, realizing the airport is unsafe for landing.
Automatic Terminal Information Service (ATIS) is a continuous broadcast of non-control information in selected high-activity terminal areas. To relieve frequency congestion, pilots are urged to listen to ATIS, and on initial contact, to advise controllers that the information has been received by repeating the alphabetical code word appended to the broadcast. For example: “information Sierra received.” The phrase “have numbers” does not indicate receipt of the ATIS broadcast.
When transmitting an altitude to ATC (up to but not including 18,000 feet MSL), state the separate digits of the thousands, plus the hundreds. For example, 13,500 is “one three thousand five hundred” and 4,500 is “four thousand five hundred.”
At airports with operating air traffic control towers (ATCT), approval must be obtained prior to moving an aircraft onto the movement area. Ground control frequencies are provided to reduce congestion on the tower frequency. They are used for issuance of taxi information, clearances and other necessary contacts. If instructed by ground control to “taxi to” a particular runway, the pilot must stop prior to crossing any runway. A clearance must be obtained prior to crossing any runway.
Aircraft arriving at an airport where a control tower is in operation should not change to ground control frequency until directed to do so by ATC.
The key to operating at an airport without an operating control tower is selection of the correct Common Traffic Advisory Frequency (CTAF). The CTAF is identified in appropriate aeronautical publications and on the sectional chart. If the airport has a part-time air traffic control tower, the CTAF is usually a tower frequency. If a Flight Service Station (FSS) is located on the airport, they will usually monitor that frequency and provide advisories when the tower is closed. Where there is no tower or FSS, UNICOM, (if available) is usually the CTAF. UNICOM is limited to the necessities of safe and expeditious operation of private aircraft pertaining to runways and wind conditions, types of fuel available, weather, and dispatching. Secondarily, communications may be transmitted concerning ground transportation, food, lodging and services available during transit. When no tower, FSS, or UNICOM is available, use MULTICOM frequency 122.9 for self-announce procedures. See Figure 6-14.

Figure 6-14. Summary of recommended communications procedures
Radar-equipped ATC facilities provide traffic advisories and limited vectoring (called basic radar service) to VFR aircraft, provided the aircraft can communicate with the facility, is within radar coverage, and can be radar-identified.
Stage II service provides radar advisories and sequencing for VFR aircraft. Arriving aircraft should initiate contact with approach control. Approach control will assume Stage II service is requested, unless the pilot states that the service is not wanted. Pilots of departing VFR aircraft should request Stage II terminal radar advisory service from ground control on initial contact.
At some locations Stage III service has been established to provide separation between all participating VFR aircraft and all IFR aircraft in the terminal radar service area (TRSA). Unless the pilot states “negative Stage III” on initial contact with approach control, the service will be provided.
Traffic advisories given by a radar service will refer to the other aircraft by azimuth in terms of the 12-hour clock, with twelve o’clock being the direction of flight (track), not aircraft heading. Each hour is equal to 30°. For example, an aircraft heading 090° is advised of traffic at the three o’clock position. The pilot should look 90° to the right of the direction of flight, or to the south. In Figure 6-15, traffic information would be issued to the pilot of aircraft A as twelve o’clock. The actual position of the traffic as seen by the pilot of aircraft A would be two o’clock. Traffic information issued to aircraft B would also be given as twelve o’clock, but in this case, the pilot of B would see traffic at ten o’clock.

Figure 6-15. Traffic advisory
These radar programs are not to be interpreted as relieving pilots of their responsibilities to see and avoid other traffic operating in basic VFR weather conditions, to maintain appropriate terrain and obstruction clearance, or to remain in weather conditions equal to or better than the minimum required by FAA regulations. Whenever compliance with an assigned route, heading, and/or altitude is likely to compromise pilot responsibilities respecting terrain, obstruction clearance, and weather minimums, the controller should be so advised and a revised clearance or instruction obtained.
[10-2024]