This VATCAN Centre Controller Study Guide outlines duties and responsibilities for Controllers operating this position. Centre Controllers are primarily responsible for protecting the airspace surrounding an IFR filed aircraft. If a Controller allows two or more aircraft to breach protected airspace, an inquiry follows to determine the causes and apply corrective measures. Moving aircraft safely and efficiently primary tasks for controllers and aircraft operators. Other duties may be taken on by a Centre Controller as workload permits.

Centre’s airspace is a large geographical area that may be subdivided in busy corridors. For example, an area within the Toronto FIR that may have a large volume of traffic may have one Centre Controller working aircraft up to FL220 and another Centre Controller, covering the same geographical area, from FL220 to FL590.

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SECTION 1– FIRs (FLIGHT INFORMATION REGIONS)

Canadian airspace is divided into seven domestic FIRs: Vancouver, Edmonton, Winnipeg, Toronto, Montreal, Moncton and Gander Domestic Flight Information Regions. The International Civil Aviation Organization (ICAO) has designated Gander Oceanic as another FIR to provide services and information for aircraft traveling over the Atlantic Ocean. All FIRs are bordered and extend from ground or sea level up to FL600.

An upper tier of high-level airspace varies in three areas across Canada: Southern Control Area (SCA), Northern Control Area (NCA) and Arctic Control Area (ACA). High-level airspace for each area is: SCA -18,000 feet ASL and above, NCA - FL230 and above, ACA - FL270 and above.

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SECTION 2 – CANADIAN AIRSPACE

Class A

IFR-only, high-level airspace. Dimensions vary by Control Area. For example in Southern Control Area Airspace, Class A starts at 18,000 and up. In Northern Control Area, Class A starts at FL230 and up.

Class B

Provides air traffic control service to IFR and VFR aircraft. Separation is provided to all controlled aircraft in this airspace. Generally comprised of all low-level airspace between 12,500 feet and 17,999 feet, Control Zones and some Terminal Control areas. All aircraft operating in Class B airspace require two-way communication with ATC and a working transponder - which reports pressure altitude.

Class C

Controlled airspace, which allows both IFR and VFR traffic. Generally designated for higher traffic volume control zones or Terminal areas and ATC separation is provided to IFR aircraft. VFR aircraft require clearance form ATC to enter and are required to have a functioning Mode C transponder plus an operational radio for communication. ATC will provide ATC service to VFR aircraft in order to avoid conflicts with other aircraft.

Class D

Controlled airspace, which allows both IFR and VFR traffic. Generally designated for lower traffic volume control zones or Terminal areas and ATC separation is provided to IFR aircraft within Class D airspace. VFR aircraft require clearance from ATC to enter and the aircraft must have a functioning Mode C transponder plus an operational radio for communication. ATC will provide traffic advisories aircraft. When ATC staff is not available within Class D airspace it then becomes Class E airspace.

Class E

An area requiring IFR separation but no VFR requirements. Aircraft operating within this airspace require a working transponder, which reports pressure altitude. Generally areas such as control zones that do not have a tower, low level airways, transition areas that would include extensions.

Class F

Special airspace with defined dimensions and one of two types: Advisory or Restricted. Class F airspace is published on VFR, High and Low level charts. The interpretation of each class F airspaces codes is found on the charts legend.

Example: CYA 524(S) To 7000 1 May/1Dec Daylight. CY=Canada, A=Advisory, 524=Ontario code which can be between 501 to 599, (S)=Soaring, 7000=Up to 7000 feet, 1May/1Dec=Between May 1 and Dec 1, Daylight=during daylight hours. Aircraft may operate in Class F A-advisory but are restricted operations in Class F R-restricted airspace.

Class G

All uncontrolled airspace of which ATC does not have any responsibility or authority to provide services. When requested by pilots ATC may provide flight following if workloads permit.

Note: Other airspace areas are Designated Mountainous Regions, Standard Pressure Region and Altimeter Setting Region. For the purposes of this document we will not engage into a description of these airspaces at such time.

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SECTION 3 - ALTITUDE ASSIGNMENTS

Care must be taken to ensure proper enroute altitude assignment, MOCA (Minimum Obstruction Clearance Altitude), MEA (Minimum Enroute Altitude) and MRA (Minimum Reception Altitude).

Proper Cruise Altitude Assignments - all headings magnetic

Below 18,000 feet -

IFR and CVFR - 000-179^o: Odd-Thousands Ft. ASL

IFR and CVFR - 180-359^o: Even-Thousand Ft. ASL

VFR - 000-179^o: Odd Thousands PLUS 500 Ft. ASL

VFR –180-359^o: Even-Thousands PLUS 500 Ft. ASL

Above FL180 – IFR Only

FL180 through FL280

000-179^o: Odd-Thousands Ft. ASL (FL190+) - 2000 foot intervals

180-359^o: Even-Thousands Ft. ASL (FL180+) - 2000 foot intervals

FL290 through FL590

000-179^o - 4000 foot intervals: FL290, 330, 370, 410, 450, 490, 530, 570

180-359^o- 4000 foot intervals: FL310, 350, 390, 430, 470, 510, 550, 590

RVSM (Reduced Vertical Separation Minima)

Reduced Vertical Separation Minima (see www.eur-rvsm.com) implements revised standards for flights operating between FL290 and FL410. Aircraft flying under RVSM need only 1000 ft. vertical separation; thus RVSM doubles airspace capacity between FL290 and FL410. Above FL410, vertical separation remains 2,000 ft.

RVSM has been implemented over Europe, the Atlantic Ocean and north of 57^o lattitude in Canada. RVSM Transition airspace within the Canadian Domestic Airspace (CDA) currently includes the Moncton FIR, Gander Domestic FIR, Vancouver FIR, and all airspace between 52^o North and 57^o North lattitudes.

Information regarding current implementation of RVSM within Canadian airspace may be found in Nav Canada's Designated Airspace Handbook - also available via the Training Materials page of the VATCAN web site.

Implementation of RVSM within southern portions of the CDA is scheduled during late 2004, concurrent with the American implementation of RVSM.

Upon implementation of RVSM in Canada, the Proper Cruise Altitude Assignments table, above, will be amended.

All MOCA (Minimum Obstruction Clearance Altitude), MEA (Minimum Enroute Altitude) and MRA (Minimum Reception Altitude) may be found on appropriate navigation charts.

Cruise Altitude Restrictions based upon Local Barometric Pressure

During periods of low barometric pressure, care must be taken when issuing cruise altitude assignments. When local, ground-level barometric pressures are below 29.92 inches Hg, minimum cruise altitudes should be assigned using this

Altitude Assignments Chart

Altimeter Setting	Lowest Flight Level
29.92 or higher	FL180
29.91 to 28.92	FL190
28.91 to 27.92	FL200
27.91 or lower	FL210

Pressure vs. Altitude Readout Changes

Pressure Altitude (Inches Hg)	Difference (Feet)
28.10	-1727
28.50	-1340
29.00	-860
29.50	-392
29.92	0
30.50	531
30.90	893
30.99	974

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SECTION 4 – SEPARATION

All aircraft flying in controlled airspace with IFR Flight plans require “protected airspace” - required and expected by pilots and controllers.

Current Minimum Vertical Separation Standards:

FL180 through FL280 - 1,000 feet,

FL290 and above - 2,000 feet.

Lateral protection on airways is depicted on aviation charts. In-trail Mach Separation Minima (below) avoid conflicts between aircraft on the same airway at the same altitude. If an aircraft is cleared to travel between two Nav aids and not on an airway, protected airspace is 45 NM each side of the track between the two Nav aids.

In-trail separation is implemented during the enroute flight phase when aircraft are at the same flight level and traveling along the same Jetway. In the table below the Mach Difference depicts speed difference between the aircraft.

Mach Difference	Minimum Separation
0.02	9 minutes
0.03	8 minutes
0.04	7 minutes
0,05	6 minutes
0.06	5 minutes

For Example {when radar control is not being used, i.e. procedural standards are applied}: Two aircraft are traveling westbound on J586 enroute from Toronto to Chicago O'Hare. If one aircraft was traveling at Mach 0.72 and the other traveling behind is at Mach 0.74, that would be a 0.02 difference and a minimum separation would have to be 9 minutes. If this separation time could not be maintained then ATC would have to instruct a change in speed or altitude for one or both of the aircraft.

Therefore: The aircraft traveling at Mach 0.72 may be asked to increase speed, if able, to Mach 0.73 and aircraft traveling at Mach 0.74 to decrease speed to Mach 0.73. If this would were not possible, one aircraft or the other would likely be instructed to change altitude to resolve the possible conflict.

Non-radar separation is implemented along with protected airspace. Radar controlled aircraft are provided with 5-mile separation. Aircraft arriving at a navaid or waypoint without further clearance will be required to enter a hold pattern. Hold pattern instructions always include an “expect further clearance” (EFC) time. In the event of a communication failure, the aircraft is normally clear to proceed from the hold along the projected flight route at the EFC time and ATC must then ensure that a path is cleared in front of the aircraft departing the hold.

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SECTION 5 - HOLDING PATTERNS

a) Holding clearances or instructions may be issued to aircraft in high traffic areas or poor weather conditions.

b) When issuing instructions for a non-published hold you must provide the holding fix name, direction from the point at which to hold, leg length, turn direction and hold altitude. Holds at navaids must include (as appropriate) the radial or heading on which to hold, a course or track to fix, and DME distances for both inbound and outbound points – in addition to leg length, turn direction and hold altitude. ATC must also provide an EFC time and, if pertinent, local communication failure procedures.

c) Standard Holding Patterns are Right-Hand.

d) Absent DME and instructions otherwise, a hold pattern at or below 14,000 feet ASL is timed at 1 minute and 1½ minutes above 14 000 feet ASL.

Example: An aircraft performing a standard hold at 8 000 feet, in still air, would fly an outbound leg for one minute, turn right at a rate one turn to the inbound heading back to the fix. Once over the fix the aircraft will turn right back to the outbound heading for one minute. Timing starts when aircraft is abeam the fix.

e) Hold entry patterns are Direct entry, Offset entry and Parallel entry - also known as modified race track, tear drop and race track. Hold entry choice is normally left to pilot discretion.

Speed Limitations in Holding Patterns:

Holding aircraft are assigned a Minimum Holding Altitude (MHA) - which is the lowest altitude for proper signal coverage and obstacle clearance - and are expected to follow the speed restrictions shown below:

Propeller driven aircraft with a MHA of FL300 and below should maintain a speed of 175 KIAS or less.

Civil turbojet driven aircraft with a MHA of 14 000 feet and below should maintain a speed of 230KIAS or less and 265 KIAS or less above 14,000 feet.

Military turbojet driven aircraft should maintain a speed of 265 KIAS or less - with exception of CT-114s which should use 175 KIAS or less and CF-5s which should use 310 KIAS or less.

Aircraft in a holding pattern while initiating a climb may use the normal climb speeds not above 310 KIAS.

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SECTION 6 - DEPARTURE AND ARRIVALS

a) Often ATC clears a flight direct to an intersection. However, some VATSIM pilots are not familiar with intersection use and other pilots may not be accustomed to operating an FMS. One viable alternative is a heading to intercept an airway that is then used for enroute navigation.

b) Real-world the controller knows the equipment onboard from the flight plan. However, on VATSIM, a controller may wish to enquire, at first, if the pilot is able to navigate using intersections.

c) Controllers may ask something like, "SAC209, after LESTER6 are you able direct BULGE?" If the pilot responds with an "affirmative", then ATC can issue clearance direct BULGE after the SID.

d) If, however, the pilot responds with a "negative", the ATC would give a clearance something like, "SAC209, after noise abatement right turn to 150 degrees for the intercept V164 airway". This allows the pilot to place his/her aircraft on an airway at which point navigation to an intersection becomes possible.

e) In areas surrounding busy aerodromes, Departure (DEP) and/or Approach (APP/ARR) Controllers are on duty to maintain a safe and expedited flow of traffic. If DEP and/or APP/ARR are not available or in lower traffic areas may issue the approach and departure clearances. Centre Controllers must be familiar with the FIR they operate in and to understand all local approach and departure procedures.

f) When providing ATC to an aircraft flying IFR you will be maintaining the “airspace to be protected” throughout its flight. An aircraft departing on an IFR flight plan from a remote airport with only a Tower Controller will require release to Centre on takeoff. After takeoff the Centre Controller assures protected airspace for the flight during the departure, enroute and possibly arrival phases.

g) Descent from Cruise - An arriving an aircraft must descend in preparation for arrival. One common tool used to determine the Top of Descent (TOD – the point at which the arrival descent begins) is the “3X Rule”: 3 x Cruise Altitude (in thousands of feet) + 10 = TOD. For example: If the flight’s cruise altitude is FL330/33,000 feet, then TOD = (33 x 3) + 10 = 109 miles.

h) If the destination airport has no on duty Tower Controller a clearance would be issued to the aircraft for the approach by Centre Control. Issuing this clearance

i) Centre Control must ensure no other IFR aircraft are released in this area until cleared aircraft has landed and reported cleared from runway. Centre will protect the airspace around destination airport – including the possibility of a missed approach. In the event of a missed approach, the arriving aircraft would hold at the chart-specified Nav aid or waypoint and await further ATC clearance.

j) Clearing an aircraft for any approach Centre always provides the local altimeter setting and identifying the source of such setting.

Here is an example of an aircraft being cleared for an approach into Tasiujaq, Quebec:

ATC: SAC209, Cleared to the Tasiujaq Aerodrome for the NDB Approach Runway 24 Approach, Report (name) NDB Outbound.

(The aircraft would fly to the NDB and perform an entry pattern as per published approach. Upon passing the NDB on its outbound leg, the aircraft will report to ATC).

SAC209: SAC209 Beacon Outbound Runway 24 Tasiujaq.

ATC: SAC209, Report Cleared of Runway.

SAC209: Will report clear of runway, SAC209

(Aircraft will execute approach in accordance to approach plate and report after landing)

REMEMBER: Published approach altitudes are MINIMUM altitude only and many experienced pilots may initially start at higher altitudes to allow for a stabilized descent.

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