Bill's NS Radio Site
Bill's NS Radio Site
DEPARTING THE AIRPORT AREA
This is the third in a series of pages intended for scanner listeners who are interested in
listening to aircraft arriving and departing
1. The Airport 2. Flight Plan, Taxi and Takeoff 3. Departing the Airport Vicinity 4. Moncton Centre and Surrounding Zones (High and Low) 5. Arriving at Halifax, Landing, and Taxi to the Gate
THIS PAGE WAS BEING
MODIFIED IN LATE JANUARY 2017 AND MAY NOT BE IN ITS FINAL FORM OR WITH ALL MAPS
AND INFORMATION INCLUDED.
PLEASE CHECK BACK FOR ADDITIONS.
Now that the aircraft has taken off, it will most likely be on the Halifax Departure frequency, 119.2, unless it is using Visual Flight Rules (VFR), in which case it will be on 118.7 MHz. Occasionally an aircraft taking off will be staying very close to the airport and perhaps looping around to land again, in which case it might remain on the tower frequency 118.4 MHz. [Note that there are times when the 119.2 transmitter is being serviced that you will find both IFR and VFR on 118.7]
Here is the chain of events for a typical airliner leaving Halifax and heading to a destination outside the region:
The aircraft has just taken off. It is climbing out, usually already cleared to 5000 feet altitude, and staying on the runway heading unless the tower has directed an immediate turnout. Once in the air and up at 1000 to 3000 feet above the ground, the pilot checks in with Halifax Terminal on 119.2 MHz. He or she will call either "Halifax Terminal" or "Departure". For Halifax there are not separalte frequencies for Arrival and Departure, so "Terminal" is good enough. They are the same thing. This call-in is to ensure that the Terminal controller has the aircraft identified on radar. Here is a typical check in and reply: "Halifax terminal, Air Canada 603, 1500 for 5, off runway 23" Terminal will reply to say the aircraft is radar-identified, and then will give the initial altitude and heading directions. An example would be "Turn right heading 275, climb to flight level 230".
The terminal control unit is located near Moncton, so even though it is called Halifax Terminal, the controller is nowhere near. There is a radar dome at Devon, just northeast of the airport, and it really makes no difference where the controller is. They never see the aircraft visually.
In the quieter hours, and with varying times, the Halifax Terminal Unit is closed down, and Moncton Centre takes over responsibility for the airspace around Halifax International. That is why you sometimes hear the pilot, on taking off, contact Moncton Centre, rather than Terminal or Departure. There is no difference in frequencies as Moncton Centre simply takes on the Halifax Terminal frequencies.
If you are at the airport and have been watching all this so far, your visual observations are now at an end unless conditions are very good. At times the departing aircraft will be lost in the clouds within ten seconds or less after takeoff. Regardless, you will not see much after takeoff as the angle of climb and the speed are such that even in the best of conditions you only have at most a minute or so to watch that aircraft. Quite often you will see the initial turn towards the destination and if lucky you can follow the aircraft as it angles up into the usually inevitable clouds.
Note that for altitudes up to and including 18000 ft the altitude is expressed in feet above sea level. Above that altitude, it is expressed as a flight level. Flight level 230 is somewhat equivalent to an altitude of 23000 feet. In the future I will explain what I mean by "somewhat" but in the meantime you should look up "flight level" in Wiki or elsewhere.
In terms of altitude, the terminal (departure) controller will normally give any jetliner a clearance to Flight Level (FL) 230. Propeller driven aircraft do not normally fly as high, nor do aircraft flying to relatively close airports such as Saint John or Moncton, and therefore they will be given lower altitude clearances. When given an altitude clearance the aircraft will generally climb to it as soon as possible and the controller does not actually dictate the angle of climb.
Direction or Heading Clearance
When an aircraft takes off from Halifax the terminal controller might give the pilot an initial heading in degrees, such as turn right heading 270, or perhaps "Continue runway heading", or might say "Steer 170 vectors for traffic". The latter is to not only give a heading but to tell the pilot this is in order to avoid other aircraft, it is normally not the heading that the pilot would like due to deviation from the overall intended path.
Eventually, or in some cases immediately, the controller will not give a heading but rather a destination. The destination is not usually the final destination but rather a waypoint that is clearly defined already by name.
The airline dispatcher will have defined the flight plan by an intended series of waypoints, or in some cases by designated airways. When the terminal controller clears an aircraft on its way from Halifax airspace it may be to a point that is on the flight plan, or perhaps due to some traffic necessity, a different one that will get the aircraft onwards to join its planned route. When the aircraft is cleared to the previously planned route, you will hear the controller say "cleared flight plan route" rather than a waypoint. But let's get back to the waypoints.
When aircraft take off from Halifax they are usually en route to a landing somewhere else. For some nearby airports ATC will clear the aircraft after takeoff immediately to a point in that other airport’s vicinity. If the other airport is farther away the flight will be in legs, with each leg defined by points along the way. In these cases, ATC will clear the aircraft to the endpoint of the first leg. For example it is very common for aircraft heading towards Toronto to be cleared to fly direct to Millinocket in Maine soon after takeoff. A distant (or not so distant) point such as this is what I refer to here as an initial waypoint. Once reaching Millinocket, in this example, the aircraft will be cleared by ATC to its next waypoint farther along its route. Note that Millinocket is an initial waypoint in this case but for another aircraft on another route it could be a second or third or greater waypoint.
Waypoints are also used locally around airports for landing approaches but in this article I am referring only to en route waypoints. In a modern airliner there is a database of all such waypoints, and the pilot need only dial in the correct abbreviation and the required heading will be displayed, or on autopilot the aircraft will on its own head that way.
The waypoints are really of two main types.
Radio Aid Defined Waypoints
These are points that are defined by a radio navigation aid that exists on the ground. Most commonly these are VOR’s of various sorts. VOR’s are VHF Omni Directional Radio Ranges that might in very rudimentary language be classified as "beacons". Aircraft with VOR equipment could fly towards or away from these beacons. Similarly the waypoint could be a radio beacon operating in the MF radio spectrum below 530 kHz. In the spectrum higher than that occupied by the VOR are the UHF beacons operated by or for the military which are called TACANS. TACAN is an acronym for Tactical Air Navigation. In some cases a VOR and TACAN are collocated and are referred together as a VORTAC.
VOR’s and TACANS are identified by three letter codes. For example the Millinocket example used above was not the town of Millinocket but rather the Millinocket VOR and its ID is MLT. ATC will commonly use the name rather than the 3-letter ID but you will hear both. While an aircraft could fly to or from MLT using its VOR equipment, it is more likely that it is only the coordinates of the VOR that are used by the GPS navigation system in the aircraft.
Many waypoints are merely points on the earth’s surface that are defined by coordinates but there is nothing there that is relevant to a navigator. For example a waypoint of this sort could be situated out in the ocean. There is no beacon to home into in this case. An example of a commonly assigned virtual waypoint in our region is ALLEX, situated on the border between Canada and the United States south of Grand Manan Island. All of these virtual waypoints are identified by pronounceable five letter acronyms. Some of them by coincidence will be actual words in English or another language, but most are not. Many times they are pronounced like real words but spelled differently. ALLEX is a case in point.
It Doesn’t Matter Really
The fact that some waypoints are “beacons” and some are not is of little or no importance in a modern aircraft. It is the coordinates that matter. The pilot chooses the waypoint by its ID by entering it, and the aircraft will fly to it, or if nothing else will tell the pilot which way to fly. One might say, why even have the physical radio aids then? Well, they are to some extent dying out but there remain many aircraft that must rely on them, or would use them in the event of a failure of the GPS system. They are likely to be around for quite a while yet but practically every month one or more of them in North America is decommissioned.
This map depicts most of the waypoints that aircraft are cleared to soon after taking off from Halifax. You will note that some are near the actual destination airport for the flight. For example an aircraft leaving Halifax and heading to Moncton will likely be “cleared to the Moncton VOR”. Note that this is not actually the Moncton airport but it is close. Once in the vicinity the controllers for that area will take over and guide the aircraft to its landing.
A few of the points shown are only rarely if ever used nowadays. At one point it was very common to hear aircraft heading to Boston to be cleared “direct SCUPP” but for some reason this waypoint is now rarely used, though it does still exist. Similarly, MAIRE, near Montreal, was commonly used. More recently the use of Kennebunk (ENE, the Kennebunk VOR) has fallen out of favour. Others rise in prominence, such as MOWND, near Fredericton, which is heard every day. Much of this has to do with the needs and preferences of airline dispatchers, based on aircraft performance and other factors.
This map is based on a Skyvector online rendition of an FAA World IFR chart. I have added the symbols and “names”.
Note that Millinocket is an extremely common initial waypoint for aircraft heading to Toronto from Halifax. Presque Ile, farther north, is commonly used by aircraft heading to Western Canada from Halifax.
Once the clearance is obtained the aircraft is established on the climb and heading, and nothing will be heard until the terminal radar controller determines that the aircraft is leaving the terminal control zone. This zone is is 35 nm circle around the airport, and with a maximum altitude of 12,500 ft ASL. Once the altitude or distance is exceeded the aircraft is handed over to the Moncton Centre low level sector controller.
The following description outlines the basic handover procedure from terminal to
low level centre control, and from low level to high level.
For information on sectors and frequencies click on this link.
LEAVING THE TERMINAL CONTROL ZONE AND ENTERING LOW LEVEL AIRWAYS (YOU SHOULD READ THE SEPARATE PAGE ON CONTROLLED AIRSPACE AND MONCTON CENTRE)
Once out of the terminal area due to distance from the airport or due to altitude, the aircraft enters the low level controlled airways system. The airspace is divided into sectors each with its own frequency. I did not say each with its own controller, as that can vary. In busier times of day there is more likely to be a controller for each sector, whereas in the middle of the night, one controller might have several sectors to watch, and several frequencies. Whenever a controller has more than one sector, the transmitters are simulcast so that he or she doesn't have to be concerned about picking a transmitter to key up. The aircraft will continue to use the specific sector frequency.
This handoff to Centre is into low level airspace. Terminal will say something like this: "Eagleflight 4458 contact Moncton Centre on 123 decimal 9." Sometimes there will be an added comment such as "and advise assigned heading".
The aircraft then switches over to the assigned frequency and reports as follows: "Moncton Centre Eagleflight 4458, [present altitude] for FL230". Moncton will reply, possibly stating that the aircraft is radar identified, but more likely just clearing it upwards to FL280 which is the uppermost level for low level airspace. At this time or at any other time there could also be a new heading or waypoint destination given. Depending on the speed and rate of climb of the aircraft, the amount of time the aircraft spends with the low level controller varies but may be quite short in duration. If the final cruising altitude will be under FL280 the aircraft will be staying with the low level controller. For example turboprop traffic such as the Dash 8 might not climb above FL250. Keep in mind that Flight Level is always referred to like this: Flight level "Two five zero" or "Two five oh", and never "Two fifty"
ON TO THE HIGH LEVEL CONTROLLERS AND
If the aircraft, e.g. jetliners, corporate jets or military, are heading on up to high level beyond FL280, they will eventually be transferred to the high level controller. This may happen prior to actually reaching that altitude. For a typical jet heading SW this will happen before they leave Nova Scotia and begin to fly over the Gulf of Maine. The following map shows the high level frequencies. Some of those shown as being located in Yarmouth and Sydney, as well as the 133.95 transmitter at Halifax are for traffic passing offshore. Note that it is quite possible to hear from Halifax aircraft speaking to Boston Center on 128.05, 134.95 and 133.45 but of course you will not hear the ground side of these communications. It is not as common to hear conversations with Gander but I have done so, as well as a few with Montreal Centre, but this has been with a rooftop beam antenna.
This ends the scanner listeners ability to listen to aircraft departing from Halifax, unless you now resort to on-line feeds from distant areas of North America and beyond. You will also be able to follow the progress of any civil flight of interest by going to radar display sites such as FlightAware, FlightRadar24 or PlaneFinder.