|
AIR TRAFFIC CONTROL COMMUNICATIONS VIRTUAL AVIATION Procedures and Phraseology (IVAO Network Information Only) |
|
| Introduction: | |
|
Safe flight operations depends on good communications. Today most of that communication is voice based - person to person communication. Human communication is prone to error and thus miscommunication between the Pilot and the ATC Controller. Therefore, standards have been developed to REDUCE confusion and ambiguity and the risk of accidents:
In real aviation, means are being developed to reduce this confusion with transmissions based upon ACARS or other such devices.
|
|
| Standard Phraseology | |
|
Standard Message Format Standard message formats should contain the following information:
Numbers Some numbers may sound alike. Some national or regional accents may also make distinguishing numbers difficult. Two type of pronunciation Number Group pronunciation Separate pronunciation, examples:
Units for Altitudes and Time: Typically, altitudes are always in feet above Mean Sea Level (MSL) Cloud ceilings are given in feet above ground level (AGL) Lower Altitudes (<18,000’ MSL) are given in “thousands” and “hundreds”
High Altitudes (>18,000’ MSL) are given as Flight Levels
Letters - Phoenetic alphabet When stating navaids DUA = Delta Uniform Alpha, etc... Time and Time Zones - ATC worldwide uses Coordinated Universal Time (UTC). UTC = local time in Greenwich, England or 0° longitude or the Prime Meridian. Previously known as Greenwich Mean Time, UTC uses a 24 hour clock - No AM or PM and No “local time”. All times given as the word “TIME” followed FOUR digits followed by “ZULU” (or “local”)..
Altimeter Settings Settings are given in inches, tenths and hundredths of mercury in the US. Settings are given in millibars of mercury internationally. Pilots are required to convert as appropriate; Stated as “Altimeter” followed by four digits:
Wind Direction and Velocity SURFACE wind direction at an airport is always measured from Magnetic North and is reported in Statute Miles for winds on the ground. WINDS ALOFT are always measured from TRUE NORTH are in KNOTS, and are reported at 3,000 ft intervals, beginning at 3,000 ft{3, 6, 9, 12, and so on}. Wind direction is always the direction the wind is blowing FROM! Directions are always rounded off to the nearest 10°. Wind intensity is measured in KNOTS (one nautical mile per hour = 1.15 SM/Hr). Winds are preceded by the word “WIND” followed by three digit direction followed by the word “AT” followed by the speed in knots (one two or three digits).
Other Wind Words
Aircraft Heading Always measured from Magnetic North. Headings are always THREE digits. 45° = 045°. Aircraft heading should state “HEADING” followed by three digit magnetic heading.
Runway Numbers Runways are numbered based on their MAGNETIC HEADING rounded to the nearest 10°.
Some large airports (KLAX & KDFW) may have 4 parallel or more runways with different numbers, e.g. 25L - 25R - 24L - 24R. Radio Frequencies Four or five digits stated individually with “point” after the third digit (MHz assumed).
ICAO uses the word “decimal” as opposed to “point” in the USA MLS and TACAN Channels TACAN channel niner zero Speeds Always measured in KNOTS and Each digit enunciated.
Air Traffic Control Facilities Name of the city or town where the facility is located followed by the type of facility.
Routes and Navigation Aid Identifiers Route type - low level Victor airway or high altitude Jet airway, with Route number.
VOR Radials, Station identifier followed by three digits followed by “radial”.
NDB Bearings, Three digit bearing followed by radio station and type.
Intersections, Five letter identifier or radial and DME from a VOR
|
|
| ATC Communications Procedures | |
|
Clearance Before operating IFR or as participating VFR in controlled airspace an aircraft must be CLEARED. A Clearance authorizes a pilot to proceed to a particular point or perform a specific maneuver. The controller will state:
Before flight a pilot wishing to fly IFR must file a flight plan in order to receive an ATC Clearance, An IFR ATC Clearance will include:
Aircraft Identification Aircraft ID is the make or model followed by the "N" number (without mentioning the "N"). In the case of scheduled commercial flights,, the airline name followed by the flight number. As an example, a Piper ID is "Cherokee Seven Two One Seven Juliet" or a Citation is "Citation Two One One Charlie Charlie". *ATC cannot abbreviate the callsign unless the pilot does it first. An example from above is the callsign will remain "Citation Two One One Charlie Charlie" unless the pilot contacts ATC and volunteer's the abbreviation, like "Citation One Charlie Charlie". This can take place only after initial contact. Likewise, the last three characters of the callsign must be used and the aircraft model will always be given. Airlines Each airline has a distinctive callsigns with a flight number assigned by the airline.
General Aviation FAA registration N-XXXXX, ID consists of aircraft type plus registration numbers/letters:
Special Use General Aviation Aircraft
ID consists of aircraft type plus registration numbers/letters
Military Aircraft Call sign varies depending on service
Special Mission Aircraft
Destination Airport Airport or clearance limit (Fix) Departure Instructions Initial route from airport of departure and the route contained in the clearance, May be a SID or a heading.
Headings (until intercepting an airway or route of flight)
Route of Flight Airway or Navaid or a series of airways or navaids to the clearance limit (airport or fix). If there are no changes in the clearance that the pilot filed. Cleared as filed If there are minor changes, Controller will state changes "then" in clearance instructions. Then as filed If there are major changes controller should alert pilot with phrase Unable routing request This will alert the pilot that a major route change is about to be read to them:
Altitude Assignment Normally - climbs and descents are expected by ATC to be made at an “optimal rate”, When within 1000’ of the assigned altitude slow climb/descent to 500 fpm. Following words may be used in an altitude assignment.
When assigning an altitude controller will tell pilot to Maintain six thousand When an IFR pilot receives a new altitude assignment they are required to report when leaving the old altitude (and required to report reaching the new altitude).
**Pilot may change altitude to stay in VMC, and Controller is no longer responsible for separating that aircraft from other IFR traffic. PILOT assumes responsibility for remaining in VMC and seeing & avoiding all other traffic IFR & VFR. When pilot requests that his IFR clearance be reissued controller must comply ASAP. Controller then reassumes responsibility IFR separation. Cruise Allows an aircraft under IFR to fly at any altitude between the assigned altitude and minimum IFR altitude for the route of flight. Allows a pilot to descend to any intermediate altitude without further clearance. When a pilot leaves any altitude they must report leaving to ATC. Once a pilot leaves any altitude they may NOT go back up without an ATC clearance Cross At - Cross Above - Cross Below Pilot does not have to climb or descend at an “optimal rate”. Pilot may climb or descend at ANY rate but they MUST meet the crossing restriction. Usually used to assure separation of aircraft. If you CANNOT meet the restriction - TELL ATC IMMEDIATELY! Pilot’s Discretion Pilot may decide when to begin the climb or descent. Usually allows aircraft to remain at higher altitude longer to conserve fuel. Also allows pilot to make intermediate level off, but you cannot climb back up after clearing a higher altitude. Required Reports Typical reports include position and altitude. ATC may also include requests in the ATC Clearance
|
|
| Holding Instructions | |
|
Holding instructions should include:
|
|