Air Traffic Control Tower

Visual Flight Rules:

• Pilot: "[Agency], [Callsign], [Location], [ATIS/ASOS/AWOS Code] [Request]"
• Pilot: "Danbury Clearance, Cessna One Seven Two Seven Victor at Arrow, Information Alpha, VFR to the west, requesting 4,500"

Instrument Flight Rules:

• Pilot: "[Agency] clearance, [Callsign] with [ATIS/ASOS/AWOS Code], IFR to [Destination] on request" OR simply "[Agency] clearance, [Callsign] IFR to [Destination]"
• ATC: "[Callsign], I have your clearance, advise when ready to copy"
• Pilot: "[Callsign], ready to copy"
• ATC: "Cessna One Seven Two Seven Victor, is cleared to Navy Pensacola via direct Montgomery, Pecan, Valdosta, Tallahassee, then as filed. Maintain runway heading for vectors on course. Climb to and maintain one zero thousand. Expect flight level two seven zero ten minutes after takeoff. Contact Meridian Departure Control on two seven six point four. Squawk four seven one zero. The reason for the change of flight plan is a line of a severe thunderstorm in the vicinity of Jacksonville""

Uncontrolled Airport Considerations:

• 

• At an uncontrolled field, if a clearance is required, you may:
  1. Depart VFR and contact Terminal Radar Approach Control (TRACON)/Air Route Traffic Control Center (ARTCC) while VFR airborne
  2. Use the Ground Communication Outlet (GCO), which a is radio to phone connection to Air Traffic - If the GCO only connects to Flight Service, contact Air Traffic via the telephone number provided
  3. Frequencies are found in the Chart Supplement U.S.
  4. Remote Communications Outlet (RCO) frequency for Flight Service or Remote Transmit Receive Outlet (RTR) frequency for Air Traffic
     • To use an RCO/RTR, contact FSS on a VOR with voice capability: "Danbury Radio, Cessna one-seven-two-seven-victor at Danbury Airport, Delta, X-ray, Romeo, one one twenty-two point six"
     • Upon acknowledgment from FSS, request the clearance by providing your location, your request (IFR clearance), your destination, and your planned runway (think possible departure procedure assignment), and when you'd like to depart (think release and clearance void times)
  5. Telephone the clearance/delivery number found in the Chart Supplement [Figure 2]
     • Be ready to provide your callsign, departure airport, departure runway, and destination
     • Calling before engine start with enough time to start, taxi, and takeoff eases receipt of the clearance in a quite environment and allows time for discrepancies to be resolved
     • Calling early also allows for a targeted clearance void time, potentially avoiding sitting at the end of the runway burning fuel and waiting on the clock
     • Usually one phone number works for the entire facility, meaning you can use a nearby airport if none is published (or can be found) for the current airport

• 

Clearance Limit:

• A clearance limit will authorize flight to a point, be it an airport of fix
  • Many airports and associated Navigation Aids (NAVAIDs) are collocated with the same name and/or identifier, requiring care to ensure a clear understanding of the clearance limit
• When the clearance limit is the airport of intended landing, the clearance should contain the airport name followed by the word "airport"
  • "Cleared to [Airport]"
• When the clearance limit is a NAVAID, intersection, or waypoint and the type is known, the clearance should contain type
  • "Cleared to [Fix], expect further clearance in three zero minutes"
• At some locations, a short-range clearance procedure is utilized whereby air traffic control issues the clearance to a fix within or just outside of the terminal area, and pilots are advised of the frequency on which they will receive the long-range clearance direct from the center controller

Departure Instructions:

• Where the volume of traffic warrants, departure procedures are issued to separate a departure from other air traffic in the terminal area
  • "Maintain runway heading for vectors on course" or
  • "Cleared to Teterboro Airport via the Bangor Three Departure, then as filed"

Route of Flight:

• Usually air traffic control issues, clearances for the altitude or flight level, and route filed by the pilot
  • Due to traffic conditions, it may be necessary for ATC to specify an altitude or flight level or route different from that requested by the pilot
  • Flow patterns have been established in certain congested areas or between congested areas whereby traffic capacity
    • These flow patterns increase traffic capacity
    • Information on these flow patterns is available in offices where preflight briefings are available or where flight plans are accepted
• When required, air traffic clearances include data to assist pilots in identifying radio reporting points
  • "via direct Montgomery, Pecan, Valdosta, Tallahassee, then as filed"
• It is the responsibility of pilots to notify ATC immediately if their navigation equipment cannot receive the type of signals they must utilize to comply with their clearance
  • ATC issues clearances per the filed flight plan suffix

Altitude Data:

• ATC nomrally issues clearances for the altitude or flight level filed by the pilot
• The altitude or flight level instructions in an ATC clearance normally require the pilot to "maintain" the altitude or flight level at which the flight will operate when in controlled airspace
  • "Climb to and maintain one zero thousand"
• When possible, if the altitude assigned is different from the altitude requested by the pilot, ATC will inform the pilot when to expect climb or descent clearance or to request altitude change from another facility
  • "Expect flight level two-seven-zero ten minutes after takeoff"
• If not given the desired altitude before crossing the boundary of the ATC facility's area, the pilot should reinitiate the request with the next facility
• ATC may use the term "cruise" instead of "maintain" to assign a block of airspace to a pilot from the minimum IFR altitude up to and including the altitude specified in the cruise clearance
  • The pilot may level off at any intermediate altitude within this block of airspace
  • Climb/descent within the block is at the discretion of the pilot
  • However, once the pilot starts descent and verbally reports leaving an altitude in the block, the pilot may not return to that altitude without additional ATC clearance

Departure Frequency:

• ATC advises pilots of the frequency on which they will receive the long-range clearance direct from the center controller
  • "Contact Meridian Departure Control on two seven six point four"

Transponder Code:

• Transponder codes are assigned to link your aircraft to your assigned route/flight plan
  • "Squawk four seven one zero"
• Learn more about the transponder and codes here

Holding Instructions:

• Whenever cleared to a fix other than the destination airport (clearance limit), and delays are expected, it is the responsibility of the ATC controller to issue complete holding instructions (unless the pattern is charted), an EFC time, and the best estimate of any additional en route/terminal delay
  • If the holding pattern is charted and the controller doesn't issue complete holding instructions, the pilot must hold as depicted on the appropriate chart
  • When the pattern is charted, the controller may omit all holding instructions except the charted holding direction and the statement "AS PUBLISHED," e.g., "HOLD EAST AS PUBLISHED"
  • Controllers must always issue complete holding instructions when pilots request them
• If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC for holding instructions before reaching the fix
  • This procedure will eliminate the possibility of an aircraft entering a holding pattern other than that desired by ATC
  • If unable to obtain holding instructions before reaching the fix (due to frequency congestion, stuck microphone, etc.), hold in a standard pattern on the course on which you approached the fix and request further clearance as soon as possible
    • In this event, the altitude/flight level of the aircraft at the clearance limit will be protected
    • Separation is provided, as required
• If still awaiting a clearance beyond the fix when the aircraft is 3 minutes or less from a clearance limit, the pilot must start a speed reduction so that the aircraft will cross the fix, initially, at or below the maximum holding speed
• When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and, whenever possible, at least 5 minutes before the aircraft reaches the clearance limit
• Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit and report leaving the clearance limit
• In the event of a two-way communications failure, pilots shall comply with Title 14 of the Code of Federal Regulations (CFR) Section 91.185

Record ATC Clearance:

• When conducting an IFR operation, make a written record of your clearance
• The specified conditions which are a part of your air traffic clearance may be somewhat different from those included in your flight plan
• Additionally, ATC may find it necessary to ADD conditions, such as particular departure route
• The very fact that ATC specifies different or additional conditions means that other aircraft are involved in the traffic situation

Clearance/Instruction Readback:

• Pilots of airborne aircraft should read back those parts of ATC clearances and instructions containing altitude assignments, vectors, or runway assignments as a means of mutual verification
• The read-back of the "numbers" serves as a double check between pilots and controllers and reduces the kinds of communications errors that occur when a number is either "misheard" or is incorrect
  • Include the aircraft identification in all read-backs and acknowledgments to help controllers determine that the correct aircraft received the clearance or instruction. The requirement to include aircraft identification in all read-backs and acknowledgments becomes more important as frequency congestion increases and when aircraft with similar call signs are on the same frequency
    • "Climbing to Flight Level three three zero, United Twelve" or "November Five Charlie Tango, roger, cleared to land runway nine left"
  • Read back altitudes, altitude restrictions, and vectors in the same sequence given in the clearance or instruction
  • Altitudes contained in charted procedures, such as departure procedures, instrument approaches, etc., should not be read back unless the controller specifically requests them
  • Initial read back of a taxi, departure, or landing clearance should include the runway assignment, including left, right, center, etc. if applicable

Amended Clearance:

• Amendments to an initial clearance are issued when necessary to resolve conflicts between aircraft
  • This may come in the form of a new route, holding, or change altitude before reaching the point where standard separation from other IFR traffic would no longer exist
• A pilot may wish an explanation of the handling of the flight at the time of occurrence; however, controllers are not able to take time from their immediate control duties, nor can they afford to overload the ATC communications channels to furnish explanations
  • Pilots may obtain an explanation by directing a letter or telephone call to the chief controller of the facility involved
• Pilots have the privilege of requesting a different clearance from that which ATC has issued if they feel that they have information that would make another course of action more practicable or if aircraft equipment limitations or company procedures forbid compliance with the clearance issued
  • An example might be avoiding weather the pilot sees ahead, but ATC has not yet warned them about

Coded Departure Route:

• Coded Departure Routes (CDRs) provide air traffic control a rapid means to reroute departing aircraft when the filed route is constrained by either weather or congestion
• It consists of eight-character designator that represents a route of flight
  • The first three alphanumeric characters represent the departure airport
  • Characters four through six represent the arrival airport
  • The overlying ARTCC chooses the last two
    • Example: PITORDN1 is Pittsburgh to Chicago
• CDRs are updated every 56 days
• General aviation customers who wish to participate in the program may now enter "CDR Capable" in the remarks section of their flight plan
  • When entering "CDR Capable" into the remarks section of the flight plan, the general aviation customer communicates to ATC the ability to decode the current CDR into a flight plan route and the willingness to fly a different route than filed

Special VFR Clearances:

• Find more here

Turns:

• When a heading is assigned or ATC requests a turn, pilots must promptly initiate the turn, complete the turn, and maintain the new heading unless issued additional instructions
  • ATC: "Cessna One Seven Two Seven Victor, turn left heading two-seven-zero"

Climbs and Descents:

• Pilots must commence descent upon receipt of the clearance and descend at the suggested rates until reaching the assigned altitude of 6,000 feet
  • "United Four Seventeen, descend and maintain six-thousand"

"Pilot's Discretion:"

• The term "AT PILOT'S DISCRETION" included in the altitude information of an ATC clearance means that ATC has offered the pilot the option to start climb or descent when the pilot wishes, is authorized to conduct the climb or descent at any rate, and to level off at any intermediate altitude as desired temporarily
  • However, once the aircraft has vacated an altitude, it may not return to that altitude
• When ATC has not used the term "AT PILOT'S DISCRETION" nor imposed any climb or descent restrictions, pilots should initiate climb or descent promptly on the acknowledgment of the clearance
  • Descend or climb at an optimum rate to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until reaching the assigned altitude
  • If at any time the pilot is unable to climb or descend at a rate of at least 500 feet a minute, advise ATC
• If the altitude information of an ATC DESCENT clearance includes a provision to "CROSS [fix] AT" or "AT OR ABOVE/BELOW [Altitude]," how the descent complies with the crossing altitude is at the pilot's discretion
  • This authorization to descend at the pilot's discretion is only applicable to that portion of the flight to which the crossing altitude restriction applies, and the pilot must comply with the crossing altitude as a provision of the clearance
  • Any other clearance in which pilot execution is optional will so state "AT PILOT'S DISCRETION"
    • "United Four Seventeen, descend at pilot's discretion, maintain six thousand"
      • The pilot is authorized to conduct descent within the context of the term at the pilot's discretion as described above
    • "United Four Seventeen, cross Lakeview V-O-R at or above Flight Level two zero zero, descend and maintain six thousand"
      • The pilot is authorized to conduct descent at the pilot's discretion until reaching Lakeview VHF Omni-Directional Receiver (VOR) and must comply with the clearance provision to cross the Lakeview VOR at or above FL 200. After passing Lakeview VOR, the pilot must descend at the suggested rates until reaching the assigned altitude of 6,000 feet
    • "United Four Seventeen, cross Lakeview V-O-R at six thousand, maintain six thousand"
      • The pilot is authorized to conduct descent at the pilot's discretion, however, they must comply with the clearance provision to cross the Lakeview VOR at 6,000 feet
    • "United Four Seventeen, descend now to Flight Level two-seven-zero, cross Lakeview V-O-R at or below one zero thousand, descend and maintain six thousand"
      • Promptly execute and complete descent to FL 270 upon receipt of the clearance. After reaching FL 270, the pilot may descend "at pilot's discretion" until reaching Lakeview VOR. The pilot must comply with the clearance provision to cross Lakeview VOR, at or below 10,000 feet. After Lakeview VOR the pilot is expected to descend at the suggested rates until reaching 6,000 feet
    • "United Three Ten, descend now and maintain Flight Level two four zero, pilot's discretion after reaching Flight Level two eight zero"
      • The pilot must commence descent upon receipt of the clearance and descend at the suggested rates until reaching FL 280. At that point, the pilot is authorized to continue the descent to FL 240 "at pilot's discretion"

"Immediately:"

• ATC, in certain situations, will include the word "IMMEDIATELY" in a clearance or instruction to impress the urgency of an imminent situation, and expeditious compliance by the pilot is expected and necessary for safety
  • ATC: "Cessna One Seven Two Seven Victor, turn left to two seven zero immediately"
    • The pilot must initiate a left turn as quickly as possible consistent with safety

Cleared for the Option:

• Cleared for the option gives pilots (and instructors) the flexibility to perform a desired landing to include:
  • Go-around
  • Low approach
  • Missed approache
  • Touch-and-go
  • Stop-and-go
  • Full-stop

Deviating From a Clearance:

• In accordance with FAR 91.123, pilots are permitted to deviate from a clearance under three conditions:
  • An amended clearance is obtained;
  • An emergency exists, or;
  • The deviation is in response to a traffic alert and collision avoidance system resolution advisory
• If ATC issues a clearance that would cause a pilot to deviate from a rule or regulation, or in the pilot's opinion, would place the aircraft in jeopardy, IT IS THE PILOT'S RESPONSIBILITY TO REQUEST CLARIFICATION AND/OR AN AMENDED CLEARANCE
  • Similarly, if a pilot prefers to follow a different course of action, such as make a 360° turn for spacing to follow traffic when established in a landing or approach sequence, land on a different runway, takeoff from a different intersection, takeoff from the threshold instead of an intersection, or delay operation, THE PILOT IS EXPECTED TO INFORM ATC ACCORDINGLY
  • When the pilot requests a different course of action, however, the pilot is expected to cooperate to preclude disruption of traffic flow or creation of conflicting patterns
  • The pilot must use the appropriate aircraft call sign to acknowledge all ATC clearances, frequency changes, or advisory information
• Each pilot who deviates from an ATC clearance in response to a Traffic Alert and Collision Avoidance System resolution advisory must notify ATC of that deviation as soon as possible
• In case emergency authority is used to deviate from provisions of an ATC clearance, the pilot-in-command must notify ATC as soon as possible and obtain an amended clearance. In an emergency that does not result in a deviation from the rules prescribed in 14 CFR Part 91 but which requires ATC to give priority to an aircraft, the pilot of such aircraft must, when requested by ATC, make a report within 48 hours of such emergency to the manager of that ATC facility
• The guiding principle is that the last ATC clearance has precedence over the previous ATC clearance. When amending the route or altitude in a previously issued clearance, the controller will restate applicable altitude restrictions. If altitude to maintain is changed or restated, whether before departure or while airborne, and previously issued altitude restrictions are omitted, those altitude restrictions are canceled, including departure procedures and STAR altitude restrictions. For example:
  • A departure flight receives a clearance to the destination airport to maintain FL 290. The clearance incorporates a DP, which has certain altitude crossing restrictions. Shortly after takeoff, the flight receives a new clearance changing the maintaining FL from 290 to 250. If the altitude restrictions are still applicable, the controller restates them
  • A departing aircraft is cleared to cross Fluky Intersection at or above 3,000 feet, Gordonville VOR at or above 12,000 feet, maintain FL 200. Shortly after departure, the altitude to be maintained is changed to FL 240. If the altitude restrictions are still applicable, the controller issues an amended clearance as follows: "cross Fluky Intersection at or above three thousand, cross Gordonville V-O-R at or above one two thousand, maintain Flight Level two four zero"
  • An arriving aircraft is cleared to the destination airport via V45 Delta VOR direct; the aircraft is cleared to cross Delta VOR at 10,000 feet and maintain 6,000 feet. Before Delta VOR, the controller issues an amended clearance as follows: "turn right heading one eight zero for vector to runway three six I-L-S approach, maintain six thousand"
    • Because the altitude restriction "cross Delta V-O-R at 10,000 feet" was omitted from the amended clearance, it is no longer in effect
• Pilots of turbojet aircraft equipped with afterburner engines should advise ATC before takeoff if they intend to use afterburning during their climb to the enroute altitude. Often, the controller may be able to plan traffic to accommodate a high-performance climb and allow the aircraft to climb to the planned altitude without restriction
• If ATC issues an "expedite" climb or descent clearance, and the altitude to maintain is subsequently changed or restated without an expedite instruction, the expedite instruction is canceled. Expedite climb/descent normally indicates to the pilot to use the best rate of climb/descent without requiring an exceptional change in aircraft handling characteristics. Normally controllers will inform pilots of the reason for an instruction to expedite