Located in the terminal control unit, departure control is responsible for aircraft after takeoff until hand off to the Area Control Center (ACC). Departure controllers issue various instructions to aircrews as they transition through the terminal control area and onto their assigned enroute airways. To help streamline the departure phase numerous systems and procedures are used, these include "Standard Instrument Departures" and "Flight Progress Strips".

Flight Progress Strips

Prior to pushback, a "Flight Progress Strip" is prepared for each IFR flight. These strips provide the routing information needed by controllers to issue the correct headings once airborne. As the flight progresses through the various ATC sectors a new strip is prepared prior to handoff. The flight progress strip will include the following information:

Information within the "Aircraft Identification - AI" and "Sector Fix Posting - SFP" boxes are interchangeable. For flights, as above, traveling west or southbound the "AI" information appears on the left hand side of the strip and the "SFP" information appears on the right side. This is reversed for flights traveling east or northbound.

Standard instrument departures are published procedures than an aircraft must adhere to immediately after takeoff. Because of surrounding terrain or noise abatement restrictions, these procedures detail any turns or speed and altitude restrictions pilots must comply with. Each runway may have it's own set of procedures and for this reason SID's are assigned a name and number such as, "Lester Two Departure" or "Toronto Three Departure". The specific details for a "Lester Two Departure" for runway 05 at Pearson Airport may read as follows;

"Maintain heading 057 degrees, at 1000' ASL turn left heading 047 degrees or assigned heading for vectors to assigned route. Climb to and maintain 5000' ASL."

Pilots will receive information as to which SID procedure to use as part of their initial flight plan clearance. An example may sound like this;

"Air Canada 420 cleared to the Dorval Airport via centre stored flight plan, depart runway 33, with a "Pearson 1 SID" squawk code1255"

The initial departure transmission between the pilot and controller may sound like this;

Pilot - "Toronto Departure, Air Canada 856 with you, climbing through one thousand two hundred for seven thousand off 05".

Controller - "Air Canada 856 you are radar identified, at 3600 feet turn right heading 090, maintain 7 thousand".

Departure Terminology

• Climb and Maintain (altitude) - is an instruction to climb to and level off at the specified altitude
• Proceed Direct to (VOR or Fix) - instruction to turn directly toward the fix named and fly to it
• Heading - a magnetic compass bearing
• Vectors - a controller assigned heading
• Radar Identified - phrase used by the controller when positive identification of the aircraft is made on the radar screen
• Traffic - any other aircraft in the immediate area

Transponders

The transponder system is used to provide positive aircraft identification on the air traffic controllers radar screen. The airborne transponder system consists of a control, receiver/transmitter, and a small L-bank antenna mounted on the underside of the aircraft. The ground based equipment is comprised of a transmitter/receiver, and a rotating directional antenna that is usually mounted on top of the surveillance radar antenna. Without a transponder the radar can only detect an aircraft's range and bearing, however an aircraft equipped with a transponder is able to transmit a signal which provides it's proper identification and altitude which ensures for positive control. Each flight is assigned a four number transponder code by ATC which the pilot then enters into the transponder. These same numbers are paired with the computers at the Air Traffic Control Centre. The ground based unit can now send out an special interrogation signal which is received by the airborne unit. The aircraft's transponder receives this signal and replies with a signal that is computed by the ground unit to display information such as distance, direction, and with a Mode C transponder, altitude. Should there be any confusion of an aircraft's ID the controller may request a flight to "Squawk Ident". This pilot initiated action will cause the radar ident to flash. There are thousands of transponder code combinations, however, three are internationally recognized for specific use only, they are as follows;

• Code 7500 - Unlawful Interference (Hijack)
• Code 7600 - Communications Failure
• Code 7700 - Emergencies (if unable to establish communication)

The two principal Mode of transponders in use today are Mode "A" and Mode "C".

Mode A: replies with information on the aircraft's identification only.

Mode C: replies with identification and altitude.

It should be noted that certain airspace restricts the flight of aircraft not equipped with a Mode C transponder.

Transponder Terminology

Squawk (code) - operate the transponder on the assigned code

Squawk Ident - push the transponder Ident button

Recycle Transponder - reselect the transponder and transmit the currently assigned code.

Introduction | Local Area Control | Arrivals | ACC - Enroute | FSS | ATC Transcript

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