Operations At Towered Airports

There are two kinds of airports-those with an operating control tower and those without.

There are two kinds of airports-those with an operating control tower and those without. When a part-time tower is closed, the airport is considered nontowered. Every year, there are more than 40 million arrivals and departures at FAA ATC towered airports- nearly half of these are general aviation operations.

Although it's possible for a pilot to avoid towered airports, doing so impacts the flexibility and utility of flying. Two things distinguish a towered airport. One is the presence of air traffic controllers (ATC), whose primary function is to coordinate traffic flow. The second is that a pilot must maintain two-way radio contact with the tower and obtain a clearance to enter the airspace, land, taxi, and take off.

Because of the clearance requirement, pilots generally follow different procedures than at nontowered fields. For example, a pilot approaching a nontowered airport normally would plan the arrival to make a 45-degree entry to the downwind leg of the active runway. Approaching a towered airport, however, ATC can clear you to enter the pattern at any leg. The entry point will depend on the runway in use, the direction of arrival, and the location of other arriving aircraft.

View from the Tower

A great way to get an all-encompassing view of a towered airport and also learn about operating procedures is to visit a control tower. The FAA encourages pilots to visit ATC facilities. Telephone first to make an appointment. Take a diagram of the airport and charts (sectional or IFR enroute) with you to ask questions.

The key to safe operations at towered airports, both in the air and on the ground, is awareness. Good preflight planning is essential. Focus on the task at hand, organize the cockpit to minimize your work load, and know where you are in relation to other aircraft in the vicinity.

Airport Lighting

(For further information and a complete set of approach lighting system diagrams, refer to the Aeronautical Information Manual, Chapter 2, Section 1.)

Approach lighting systems provide the basic means to transition from instrument flight to visual flight for landing.

Approach lighting systems are a configuration of signal lights starting at the landing threshold and extending into the approach area a distance of 2,400 to 3,000 feet for precision instrument runways and 1,400 to 1,500 feet for nonprecision runways.

Visual approach slope indicators (VASIs) provide visual descent guidance during the approach to a runway. The lights are arranged in bars and vary in number from two to 16. The lights are arranged so that the pilot will see the combination of lights shown here.

Precision approach path indicators (PAPIs) use light units similar to the VASI but are installed in a single row of either two or four light units. They are normally installed on the left side of the runway, and the glidepath indicators are shown below.

Runway end identifier lights (REILs) consist of a pair of synchronized flashing lights located on each side of the runway threshold.

Runway edge lights are white and outline the edges of runways at night or in restricted-visibility conditions. On instrument runways, yellow replaces white on the last 2,000 feet or half the runway length. The lights marking the ends of the runway are red for departing aircraft and green for landing aircraft.

Lights Up

Tower controllers can operate many of the airport's lights at various intensities. Ask them to turn up runway and lead-in lights when you're trying to locate the field. Most pilots prefer these lights to be dimmed for landing.

Blue taxiway edge lights outline the taxiways. Green lights mark the taxiway centerline as well as taxi paths. Yellow clearance bar lights are installed at holding positions on taxiways and at the location of an intersecting taxiway. Flashing yellow runway guard lights are installed at taxiway/runway intersections. Stop bar lights consist of a row of red lights that extend across the taxiway at the runway holding position. Following the ATC clearance to proceed, the stop bar is turned off and the lead-on lights are turned on. Pilots should never cross a red illuminated stop bar, even if an ATC clearance has been given to proceed.

Note: Not all airports are equipped with taxiway centerline lights, yellow clearance bar lights, runway guard lights, or stop bar lights.

Taxi Tips

• If in doubt about where you are while taxiing on the airport, bring the aircraft to a stop and ask Ground Control for progressive taxi instructions: "Ground, Five-Eight Quebec requests progressive taxi instructions." Never stop on an active runway after landing to ask for directions. Clear the runway first, then stop on a taxiway.
• Do not taxi onto or across a runway unless you are certain the ground controller has given you clearance to do so. If there is the slightest doubt, ask.
• At night, taxi with other pilots in mind. Minimize use of distracting aircraft lights. Use position lights at all times and the taxi light as needed, but keep strobes and landing lights off until the tower controller has issued you a takeoff clearance. Then turn on all lights. Adhere to operating time limits on lights if specified by the manufacturer.
• Always have a taxi chart available and check your assigned route against the chart before moving.

The heading indicator is as useful on the ground as it is in the air. Use it together with the taxi chart to maintain orientation.

Airport Pavement Markings

(For further information, refer to the Aeronautical Information Manual, Chapter 2, Section 3).

All runway markings are white.

Taxiway markings are yellow. The centerline is a single yellow line, and the taxiway edge is marked by a double yellow line. Dashed edge markings allow the aircraft to cross to the adjoining apron.

Runway holding position markings consist of four yellow lines-two solid and two dashed Aircraft should stop on the solid-line side. A pilot should not cross this marking without ATC clearance. An aircraft exiting the runway is not clear of the runway until all parts of the aircraft have crossed the holding position marking. These markings are installed on runways only if the runway is normally used by ATC for "land, hold short" or taxiing operations.

Airport Signs

There are many types of signs on airfields. Often, the information on the signs is also painted on the airport pavement. The following examples are described as if you were on the taxiway or runway, looking at the sign.

• Taxiway location sign: Indicates the taxiway you are on.
• Holding position sign: Hold here. From your position on the taxiway at midfield, the threshold for Runway 15 is to your left and the threshold for Runway 33 is to your right. This sign is located next to the yellow holding position markings painted on the taxiway pavement.
• ILS critical area boundary sign: Seen when exiting the runway, this sign marks the boundary of the ILS critical area. When ILS approaches are in use, be sure your aircraft has passed beyond this sign before stopping on the taxiway.
• ILS holding position sign: ATC may hold you at this sign when the instrument landing system is being used at the airport. Aircraft taxiing beyond this point may interfere with the ILS signal to approaching aircraft.
• Runway boundary sign: This sign faces the runway and is visible to pilots exiting the runway. Taxi past this sign ("dash past the dashed lines") to be sure you are clear of the runway.
• Holding position sign for approach areas: Hold here unless cleared to cross. Taxiing past this sign may interfere with arriving or departing aircraft to Runway 15.

Location and Direction Signs

• Taxiway entrance at intersection of two runways. The arrows pointing to Runways 5-23 and 9-27 indicate the approximate alignment of the runways relative to you and point to each runway threshold.
• Taxiway intersection. The orientation of these signs is from left to right in a clockwise manner. Left turn signs are on the left side of the location sign and right turn signs are on the right side of the location sign.

Other Signs

• No entry sign: Do not enter this area. Aircraft are prohibited. This sign would be found at the entrance to a one-way taxiway or at the intersection of a road intended for vehicles.
• Inbound destination sign: The military installation is to your right. Other information signs are "Cargo," "Term" (Terminal), "Ramp", etc.
• Outbound destination sign to different runways.

Planning Your Flight

The basic aircraft requirement for operating at a towered airport is a two-way radio. If your flight involves a takeoff or landing at a Class B or C airport, the aircraft also must be equipped with a Mode C transponder.

Basic planning should include knowledge of special local departure and arrival procedures for noise abatement, obstacle clearance, and traffic flow in busy terminal areas. When obtaining your preflight weather briefing from flight service, ask for any special procedures, and if you are unsure, check with an instructor based at the airport. FBOs sometimes post notices about special noise-abatement departure procedures and routes that avoid obstacles or controlled-access airspace.

Noise Abatement

Flying neighborly isn't just a good idea. At some airports, it's policy. Before flying to or from an unfamiliar airport, check with the airport manager or FBO to see if mandatory or recommended noise-abatement procedures apply. Noise-abatement procedures avoid noise-sensitive areas near the airport such as a hospital or residential area. On arrival, that could mean adjusting course to avoid those areas or remaining above traditional pattern altitudes. Departure noise-abatement procedures usually call for turning to a specified heading soon after takeoff to avoid noise-sensitive areas. Many airports place a sign at the departure end of noise-sensitive runways specifying noise-sensitive departure procedures pilots should fly. Use a best-rate climb speed, reduce to climb power, and retract flaps as soon as practical after takeoff to minimize the noise of your aircraft.

When planning your flight to or from a towered airport, look at the big picture. Is the airport near or within Class C or B airspace that will require you to communicate with approach/departure controllers, in addition to tower controllers? If you want to avoid entering Class B or C airspace (assuming that the towered airport you are using is not within the airspace), be sure you are aware of any altitude restrictions. Know the route you will use and how you will navigate-visually using landmarks depicted on the chart or with VORs, loran, or GPS. Do large aircraft operate from your departure or destination airport? Be aware of potential jet or propeller blast from larger aircraft when taxiing, and avoid wake turbulence on takeoff and approach.

Wake Turbulence

Wake turbulence is a concern whenever small aircraft share an airport with larger ones. The powerful vortices that spiral off the wing tips of heavier aircraft-turboprops and business jets, as well as airliners-can suddenly and unexpectedly toss a small airplane out of control. Always avoid the area below and behind a large aircraft. Standard air traffic control spacing of four to six miles between aircraft on approach, and two or three minutes between departures from the same or closely spaced parallel runways, offer protection. For extra insurance, be aware of wind speed and direction and adjust your approach and/or departure path to stay above and upwind of where wake vortices might linger. When in doubt, ask for extra spacing or time to allow wake vortices to dissipate.

Information about individual towered airports can be found in the Airport/Facility Directory, as well as in AOPA's Airport Directory. Changes will be publicized in Notices to Airmen-notams-which should be included in your preflight briefing from a flight service station or DUATS.

Charts

You'll need the appropriate sectional aeronautical charts and, if the airport is within or under Class B airspace, the appropriate terminal area chart.

Towered airports are depicted in blue. Information printed next to the airport symbol includes:

1. The airport name and location identifier;
2. Control tower frequency;
3. ATIS (automated terminal information service), ASOS (automated surface observation system), or AWOS (automated weather observation system) frequency, whichever is applicable to the airport;
4. Airport elevation in feet;
5. Runway lighting; and
6. Length of longest runway in hundreds of feet.

VFR charts also note if a flight service station facility is on the field, airport surveillance radar is available, the tower is part-time or a non-federal facility, if special VFR is not permitted, and the unicom and VFR advisory frequencies, if applicable. A complete explanation is printed on the chart's legend and in the NOAA Aeronautical Chart User's Guide.

Study the airport layout so you can taxi to and from the active runway without getting lost. Instrument approach procedure (IAP) charts are required for IFR operations, and they are also a great reference for the VFR pilot. All pertinent information about the airport is provided, including elevation, navigation aids, and communications frequencies, as well as a small diagram of the runway, taxiways, and ramps. If the airport has a complex runway or taxiway configuration, the IAP charts will include a separate, detailed airport diagram page. These airport diagrams are invaluable for finding your way around large airports, but never hesitate to ask for progressive taxi instructions if needed.

Navigation Aids

Become familiar with the terminal area navigation aids-the VOR, ADF, localizer, and glideslope-at the airports you'll be using. They are critical to instrument operations and can be very helpful to VFR pilots as well. It can be a challenge to find an unfamiliar airport if it's immersed in an urban sea of buildings and lights or hidden among hills. On-airport navaids, GPS, and loran make the job a lot less stressful.

Nonstandard Procedures

Be flexible. Controllers at busy airports use a variety of techniques to keep traffic flowing smoothly. You may be asked to:

• Fly a faster than normal final approach;
• Extend your downwind;
• Switch to another runway at the last minute;
• Do a 360-degree turn or S-turns on final to allow preceding traffic to clear; or
• Taxi around another aircraft in the runup area.

Be proficient so you can handle such unusual procedures safely. Remember: The pilot in command has the right to decline any procedure that may put the flight in jeopardy. Cooperate, but don't hesitate to decline a request or to change your mind if something isn't working out.

Communication

Because clearances are required to operate at towered airports, good radio communication skills go a long way toward ensuring smooth operations.

A good communications system includes at least one 720- or 760-channel transceiver with enough power to transmit and receive communications without static or interference. If the aircraft transceiver is not working properly, the communications process will be difficult and could be unsafe. Get it fixed before operating at a towered airport. A headset with an attached boom microphone and a push-to-talk switch greatly simplify the task of flying and communicating simultaneously. Just be sure the airplane is equipped with a hand-held microphone and speaker as backup in the event the headset or intercom system fails.

Even the best radios fail occasionally. When that happens, you can still receive tower instructions via light gun signals. Because we get very little practice with these signals, they're easily forgotten. We suggest you copy the light gun signal chart below and tape it to your clipboard. Acknowledge the signals by rocking your wings or flashing your landing light.

Light Gun Signals

Color and Type of Signal	Aircraft on the Ground	Aircraft in Flight
Steady green	Cleared for takeoff	Cleared to land
Flashing green	Cleared for taxi	Return for landing (to be followed by steady green at the proper time)
Steady red	Stop	Give way to other aircraft and continue circling
Flashing red	Taxi clear of the runway in use	Airport unsafe, do not land
Flashing white	Return to starting point on airport	Not applicable
Alternating red and green	Exercise extreme caution	Exercise extreme caution