Policy Letter 142
Global Positioning System (GPS) and Navigation Equipment Requirements for Instrument Flight Rules (IFR) Power-driven Aircraft.
AARX Z 5258-10925 99
This policy letter interprets Paragraph 605.18 (j) of the Canadian Aviation Regulations (CARs), navigation equipment requirements for IFR flight in a power-driven aircraft, and the installation and use of an IFR approach approved Global Positioning System (GPS) navigation system.
This policy applies to all Commercial and Business Aviation (C&BA) managers and inspectors.
The text of Paragraph 605.18(j) of the CARs states in part that:
"No person shall conduct a take-off in a power-driven aircraft for the purpose of IFR flight unless it is equipped with:(j) sufficient radio navigation equipment to permit the pilot, in the event of the failure at any stage of the flight of any item of that equipment, including any associated flight instrument display;
(i) to proceed to the destination aerodrome or proceed to another aerodrome that is suitable for landing; and
(ii) where the aircraft is operated in Instrument Meteorological Conditions (IMC), to complete an instrument approach and, if necessary, conduct a missed approach procedure."
The intent of the drafters of the Paragraph 605.18(j) of the CARs was to write the new regulation without reference to specific navigation systems, and place the onus on the pilot/operator to equip and to plan appropriately using common sense for each flight. Clearly the navigation systems aboard the aircraft need to be appropriate to the departure aerodrome, the route to be flown, the destination aerodrome and the alternate aerodrome. Making the regulation non-technology specific permits the introduction of future navigation systems, such as GPS, without the requirement to rewrite the regulation. There was no intent to increase the aircraft equipment requirement for IFR flight over and above that specified in the superceded Air Navigation Order ANO V, No. 22. Therefore, (as a minimum) an IFR aircraft requires at least two navigation systems. If one of the navigation systems fails, the remaining navigation system shall permit the aircraft to proceed to an aerodrome (destination or other suitable aerodrome), and (if IMC) complete an instrument approach and, if necessary, a missed approach procedure.
The types of navigation systems installed in an aircraft will depend on Paragraph 605.18(j) of the CARs and the kinds of navigation and approach aids available in the area where the aircraft is operated. Although most aircraft equipment exceeds the minimum navigation system requirement, a minimally equipped aircraft would traditionally have to be equipped with either two VHF Omni Range (VOR) receivers, or two Automatic Direction Finder (ADF) receivers, or a VOR receiver and an ADF receiver.
C&BA has received several requests for the interpretation of this regulation with respect to private operators or air operators planning to replace an ADF navigation receiver with an IFR approach certified GPS. These operators also fly in areas of Canada where non-directional beacons (NDB) are the prevalent navigation and approach aid. These operator's aircraft would typically be equipped with (as a minimum) two ADFs, because of the CARs navigation system requirement and the reliance on NDBs as the navigation and approach aid available in the area of operation.
NOTE: In the text that follows GPS receiver means: an approved GPS unit with an approved installation for IFR enroute, terminal and approach operations. In addition, to use the GPS receiver, the operator must be authorized by Operations Specification and pilot/crew qualified to conduct stand-alone GPS approaches.
Based on the intent of the regulation, (as a minimum) an IFR aircraft flying to a NDB only destination requires an ADF navigation receiver and at least one other navigation system. Should the ADF fail, the other navigation system shall permit the aircraft to proceed to another suitable aerodrome, and (if IMC) complete an instrument approach and, if necessary, a missed approach procedure. If the other navigation system is a GPS receiver, a GPS approach can be flown at the other suitable aerodrome. If, in the first place, the other navigation system should fail, the aircraft can proceed to the NDB destination or another suitable NDB aerodrome, and (if IMC) complete an instrument approach and, if necessary a missed approach procedure.
Similarly, the following comments are applicable to operators flying to a destination with only a stand-alone GPS approach available. Based on the intent of the regulation (as a minimum) an IFR aircraft flying to a GPS only destination requires a GPS receiver and at least one other navigation system. Should the GPS receiver fail, the other navigation system shall permit the aircraft to proceed to another suitable aerodrome, and (if IMC) complete an approach and, if necessary, a missed approach procedure. If, in the first place the other navigation system should fail, the aircraft can proceed to the GPS destination or another suitable GPS aerodrome, and (if IMC) complete an instrument approach and, if necessary a missed approach procedure. In remote areas of Canada, where non-directional beacons (NDB) are the prevalent navigation and approach aid, the other navigation system would have to be an ADF.
Private operators and air operators should be reminded that, at the time of the writing of this policy letter, GPS is approved as a supplemental navigation system for enroute and terminal operations, and as the "primary" means of navigation during a stand-alone non-precision approach. As well, Canada Air Pilot General (CAP GEN) and Aeronautical Information Publication (AIP), Rules of the Air (RAC) Section 3.14.1 do not permit the use of GPS approach minima to determine the suitability of an alternate aerodrome for flight planning purposes. This limitation restricts the flexibility to use GPS receiver, as compared to a traditional navigation aid such as VOR or ADF. Careful route analysis and flight planning is required. The global navigation satellite system (GNSS) Implementation Team (GIT) is considering relaxing this limitation somewhat, but certain conditions will still apply until such time as measures to reduce the probability and effects of GPS interference, and therefore improve GPS availability, continuity and integrity.
Operators should be directed to the latest AIP Aeronautical Information Circular (AIC) pertaining to IFR Approval to Use the GPS in Canadian Domestic Airspace for the latest information.
Finally, C&BA intends to introduce NPAs to Subpart VII of the CARs, which will create a higher safety standard (than that specified in Subpart VI of the CARs) for avionics equipment in aircraft operated in commercial passenger-carrying IFR operations.
Based on the above analysis, an aircraft equipped with (as a minimum) a single ADF receiver or a VOR receiver, and a GPS receiver meets the intent of Paragraph 605.18(j) of the CARs. Conducting an IFR flight with this minimally equipped aircraft would require careful planning. The planning would take into account the navigation aids serving the area of operation, the qualifications of the operator and pilot/crew, and the restrictions on the use of GPS in the selection of an IFR alternate aerodrome.
For operators flying in areas of Canada where non-directional beacons (NDB) are the prevalent navigation and approach aid, the replacement of one of two installed ADF receivers with an approved GPS unit with an approved installation for IFR enroute, terminal and approach operations meets the intent of Paragraph 605.18(j) of the CARs, provided the operator and pilot/crew are authorized by Operations Specification to conduct stand-alone GPS approaches.
This policy letter will be revised when improvements are made to GPS, or amendments are published regulating a higher safety standard for avionics in commercial operations.
This Policy Letter is designated AARX No. 142.
Commercial &Business Aviation
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