Wednesday, September 26, 2018
Transport Canada - Aviation Safety Letter Instrument Approach Non-Conformance at Uncontrolled Aerodromes Within Controlled Airspace

Instrument Approach Non-Conformance at Uncontrolled Aerodromes Within Controlled Airspace

by Mike Paddon, Civil Aviation Safety Inspector, System Safety, Atlantic Region, Civil Aviation, Transport Canada

A recent search of the Civil Aviation Daily Occurrence Reporting System (CADORS) database indicates that there may be some confusion or misinterpretation of procedures associated with adherence to instrument approach clearances, as issued by air traffic control (ATC), to aircraft that are conducting approaches into uncontrolled aerodromes that lie within controlled airspace. Class E airspace, for example, is controlled airspace for IFR traffic, yet, in a number of instances, aircrews have deviated from established approach procedures. The following accounts are representative of events that have been captured in the CADORS.

The twin turbo-prop commuter aircraft enroute from ____ to ____ was cleared for a straight-in instrument landing system (ILS) XX approach via ____. The pilot received and read back the clearance correctly. The pilot deviated from the clearance without ATC authorization, commencing a right 360° turn after crossing through the approach to Runway XX and then rejoining final approximately four miles from the threshold…

The arriving aircraft was cleared for a straight-in back course Runway YY approach via ___. The pilot accepted the clearance and was switched over to the flight service station (FSS). Ten minutes later the pilot turned right toward the beacon thus cutting inside the specified fix by six miles without advising the FSS or requesting a change to the clearance.

The arriving aircraft deviated from the approach clearance (straight-in back course Runway ZZ via the intermediate fix [IF]) without prior approval. There was departing traffic on Runway ZZ…

Clearly, any such deviations from approach clearances may present a hazard in terms of potential for conflict with other arriving and departing traffic. It is incumbent upon crews to contact ATC and request a clearance amendment rather than acting unilaterally to expedite or otherwise modify the approach profile. Under circumstances where some doubt or confusion may exist regarding an approach clearance, as issued and accepted, timely and concise clarification with the ATC unit is appropriate. If, after switching from ATC to a mandatory frequency, an approach clearance amendment is desired, a request can be communicated to the flight service specialist who can then facilitate the request with ATC.

Canadian Aviation Regulation (CAR) 602.127(1) states the following:

“Unless otherwise authorized by the appropriate air traffic control unit, the pilot-in-command of an IFR aircraft shall, when conducting an approach to an aerodrome or a runway, ensure that the approach is made in accordance with the instrument approach procedure.”

In an effort to dispel any misinformation that may exist, an extract from section RAC 9.3 of the Transport Canada Aeronautical Information Manual (TC AIM) is reproduced below:


….When an approach clearance is issued, the published name of the approach is used to designate the type of approach if adherence to a particular procedure is required. If visual reference to the ground is established before completion of a specified approach, the aircraft should continue with the entire procedure unless further clearance is obtained.




The number of the runway on which the aircraft will land is included in the approach clearance when a landing will be made on a runway other than that aligned with the instrument approach aid being used.



If the pilot begins a missed approach during a circling procedure, the published missed approach procedure as shown for the instrument approach just completed shall be flown. The pilot does not use the procedure for the runway on which the landing was planned.

At some locations during periods of light traffic, controllers may issue clearances that do not specify the type of approach.



When such a clearance is issued by ATC and accepted by the pilot, the pilot has the option of conducting any published instrument approach procedure. In addition, the pilot also has the option of proceeding by the route so cleared by ATC in a previous clearance, by any published transition or feeder route associated with the selected procedure, or by a route present position direct to a fix associated with the selected instrument approach procedure. Pilots who choose to proceed to the instrument procedure fix via a route that is off an airway, air route or transition are responsible for maintaining the appropriate obstacle clearance, complying with noise abatement procedures and remaining clear of Class F airspace. As soon as practicable after receipt of this type of clearance, it is the pilot’s responsibility to advise ATC of the type of published instrument approach procedure that will be carried out, the landing runway and the intended route to be flown.

This clearance does not constitute authority for the pilot to execute a contact or visual approach. Should the pilot prefer to conduct a visual approach (published or non-published) or a contact approach, the pilot must specifically communicate that request to the controller.

Upon changing to the tower or FSS frequency, pilots should advise the agency of the intended route and published instrument approach procedure being carried out.

The pilot should not deviate from the stated instrument approach procedure or route without the concurrence of ATC because such an act could cause dangerous conflict with another aircraft or a vehicle on a runway….”

When operational pressures enter the equation and are compounded by a less than complete understanding of the approach clearance, the potential for conflict is increased. If in doubt, communicate any concerns and seek clarification or amendment from the appropriate air traffic services (ATS) unit.


This article was published by Transport Canada in TP 185E -. Reprinted with permission

Add comment

Security code