Aviation Topic of the Week
By Michael Oxner, March 28, 2004


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This week's topic:
IFR to Destination Without IFR Approach

Most small airports in Canada don't have published instrument approach procedures. How does an IFR pilot get to such an airport? This week we'll look at that issue, and what to expect from ATC.

Basics
Flight Planning to Destination with no Published Approach
Controlled Airspace
What to Expect from ATC
VFR Weather Encountered
    What Should a Pilot Do?

Basics

Without an IFR approach, an airport with true IFR weather is basically inaccessible. The problem comes down to one of published tracks and altitudes that would allow a pilot to descend and break cloud. After all, that's what an instrument approach procedure is all about -- allowing a pilot to descend on specified courses, using positive track guidance to ensure aircraft placement, to the point where he can see the airport and then take over visually to land the aircraft. All instrument approach procedures are published with a Missed Approach Point (MAP) and if the pilot is unable to make visual contact with the runway environment by this point, he must go around. Airports which have more traffic (or more need for use) will often have more precise approach aids (such as ILS, Cat II ILS, or even Cat III ILS) which allow aircraft to descend to lower altitudes with lower visibility requirements, all of this leading up to a better chance of seeing the airport before hitting the point where a descision to go around must be made.

Without an instrument approach aid, a pilot has only the old rule to use: While flying IFR, 1,000 feet above the highest obstacle (including terrain) within a 5 NM radius of the aircraft except while taking off or landing. This doesn't include hoping to find one's way while descending through cloud. Instrument approaches are planned and surveyed for such a reason. Remember also that this 1,000 feet will change to 1,500 or 2,000 feet when flying within one of the Designated Mountainous Areas, which include the entire west coast, much of the east coast and into the Canadian Archipelago up north. This is quite restrictive when it comes to breaking cloud to land, wouldn't you think?

Flight Planning to Destination with no Published Approach

The biggest thing to figure out when planning a flight to such a destination is a good, safe minimum IFR altitude for the area of concern. The lower the altitude you can find, the better your chances are of getting in. One method of finding an appropriate altitude is to look at charts and look for published altitudes that cover your operation. For example, if an destination airport is near another airport that has published approach procedures, perhaps the 25 NM safe altitudes published on the intrument approach procedures will stretch far enough to give you something to work with. If not, perhaps the 100 NM safe altitudes do. The LO (Low Level Enroute) charts also have AMAs (Area Minimum Altitudes) which are largely restrictive as minimum altitudes, but they may provide you with the only numbers you can find. Failing all of that, you may have to start doing some intensive research with topographical maps to find something usable. The important thing is to do all of this ahead of time, before you get in the aircraft. This way, you'll know exactly how low you can safely descend in the event that your destination is covered with cloud. In the cockpit when you get there is a bad time to start thinking of this sort of thing.

Controlled Airspace

As an aside, most aerodromes that fit into the "approachless" category are not contained within controlled airspace. There is no control zone extending to the ground, and most likely there is no transition area even dropping the base of controlled airspace down low. While I don't have statistics, many of these airports will underlie controlled airspace based at altitudes like 2,200 AGL (for the case of control area extensions), above 12,500 ASL (where 12,500 is not included in the controlled airspace, that's why it's worded that way), or even higher. Class A airspace is based at 18,000 ASL (in Canada, we say FL180 and above is in controlled airspace) in the Southern Control Area, FL230 in the Northern Control Area, and FL270 in the Arctic Control Area. A basic word description of the latter has the NCA containing southern Nunavut (including Baffin Island) and eastern Northwest Territories, while the ACA contains the Canadian Archipelago and the seas north of the Yukon. Everything else in Canada is in the SCA.

What to Expect from ATC

The AIP Canada, RAC 9.4, gives pilots an idea of what to expect from ATC when approaching destination. For aircraft operating on airways, ATC is not permitted to issue a clearance to an aircraft to fly below the Minimum Enroute Altitude (MEA). This is because the MEA is the lowest altitude at which signal coverage for NAVAIDs making up the airway is expected. When a Minimum Obstruction Clearance Altitude (MOCA) is published, ATC may approve a pilot's request to operate down to that altitude, but not below it. Off airways, or in the airspace associated with an airway but when another form of navigation is being used to position the aircraft (such as using RNAV, GPS, etc to fly directly from point to point), ATC may approve down to another form of minimum IFR altitude, but not below it. It is at this point that the pilot must break out of cloud be able to see his destination, or at least be able to continue VFR from that point. Finding reasonable breaks in clouds with recognizable landmarks visible, and so forth.

The way the AIP words it is related mostly to airways, as was described in the preceding paragraph. By prior arrangement with ATC, the MEA will be protected for the pilot wishing to descend below the MEA to the MOCA. That way, the pilot can make the descent to the MOCA, attempt to gain visual access to the field, and climb back up to the MEA knowing that no other traffic will be there. The reason this should be prior arranged is mainly in case the pilot is unable to communicate with ATC down low. In fact, the pilot may not even be able to communicate directly with ATC while at the MEA in some areas. In any case, ATC will not, if asked to protect the MEA for a pilot descending below it, clear other traffic to operate at the MEA for a specified time period. The AIP states that this time period will be:
  1. until the pilot files an arrival report (by radio, by relay through another aircraft, by telephone, etc)
  2. for 30 minutes; to allow descent to the MOCA and to return to the MEA when communication is restored with ATC
  3. if ATC does not hear from the pilot under [either of the first two circumstances above], until the aircraft is estimated to have arrived at the filed alternate plus 30 min.
In my experience so far, I have not had to go beyond 1 or 2 above. Typically it's a fairly rapid process. The aircraft either lands, or descends and climbs back up and requests further clearance to somewhere else.

If there is no airway, the pilot must have a good idea of the lowest altitude he can use. He can then request descent to that altitude and state his intentions. Again, by prior arrangement, he can have an altitude protected for him to climb back up to in the event he doesn't establish ground contact at that altitude. This is probably more likely, in that many smaller airports do not underlie and airway. In all likelihood this is the more likely situation to be in, but it could be handled in much the same way as the RAC 9.4 demonstrates.

VFR Weather Encountered

All of the above information assumes the pilot is IFR in Instrument Meteorological Conditions (IMC). If the pilot encounters good weather while in the cruise descent, or finds a good break in cloud when he descends to his minimum IFR altitude, he simply carries on and lands, flying in accordance with VFR. All rules regarding the airport have to be respected, too, such as where and how to join the traffic pattern, any mandatory frequency calls required, and so forth. As usual, an IFR aircraft incurs no priority over VFR aircraft in the area.

What Should a Pilot Do?

By far the easiest thing from ATC's point of view if a pilot breaks into VMC and can continue to destination that way is to cancel IFR. In Canada, canceling IFR means that a pilot no longer requires an IFR clearance to allow him to do what he wants. To ATC, it means that they no longer have their hands tied by having to provide separation between you and other traffic. This is helpful to ATC since such situations can be difficult to monitor if the airports involved are in outlying areas, perhaps below radar and frequency coverage. As for pilots, it means they can do what they want without first getting approval from ATC.

Canceling IFR in Canada does not mean that the flight plan is closed, however. Since the pilot is still technically operating on an IFR flight plan, the ACC must still receive an arrival report. This is to ensure that the pilot still has alerting services at destination. That way, if the aircraft crashes on short final, at least one agency will be looking for him.

If a pilot who has canceled IFR is satisfied that someone else is out there looking for him in the event something goes wrong, he may choose to close his IFR flight plan as well. This will terminate alerting services provided by the ACC. ATC will ask a pilot who elects to cancel IFR if he is closing his flight plan as well. If the answer is, 'yes,' ATC will simply take down the information on the aircraft and that is that. If the pilot says, 'no,' and elects to keep the flight plan open, ATC will still expect (and will go looking for, if necessary) an arrival message, even though they will no longer provide separation. Closing the flight plan at this point may be an easier option if communication of an arrival report may be difficult at destination due to a lack of communication facilities.

If a pilot elects not to cancel IFR upon entering VMC, he may continue as already coordinated with ATC. As mentioned above, ATC will protect the minimum IFR altitude as appropriate until they hear further from the pilot, either in the form of an arrival message or contact indicating that the pilot has decided he won't or couldn't land and wants further clearance from ATC.




This issue has caused some concerns but it really isn't all that difficult once you understand the ins and outs. I hope I've presented a good picture here of how things do and can work for both ATC and pilots. My e-mail address, should you feel otherwise, is moxner@nbnet.nb.ca, and I'm always open to feedback. Thanks for taking the time to read, and thanks for taking the time to write!