Advisory Circulars

AIR CARRIER ADVISORY CIRCULAR


No. 0123R

2004.03.25

Use of Global Positioning System for Instrument Approaches

Purpose

This Commercial and Business Aviation Advisory Circular (CBAAC) No. 0123R supersedes Air Carrier Advisory Circular No. 0123 dated 1997.05.29. Since 1997 a number of changes have taken place with respect to the operational usage of global positioning system (GPS). This CBAAC addresses those changes and provides further guidance on a standardized training curriculum as well as links to useful training material. The purpose of this CBAAC is to continue to ensure the safe usage of GPS as an approach aid in commercial aviation. To this end, Transport Canada (TC) has established minimum requirements for GPS avionics installations, standard operating procedures, training and checking for air operators.

Applicability

These requirements apply to the use of GPS by holders of an Air Operator Certificate (AOC) issued under Part VII of the Canadian Aviation Regulations (CARs) to conduct stand alone GPS approaches under Instrument Flight Rules (IFR).

The Canadian Business Aviation Association (CBAA) is responsible for GPS policy associated with Subpart 604 operators.

non-precision, Wide Area Augmentation System based, Local Area Augmentation System based and Special Category 1 type approaches, but excludes GPS overlay approaches where the procedure is flown in accordance with a published procedure based on a conventional ground based Navigation Aid (NAVAID) and the conventional ground based NAVAID is monitored throughout the approach. GPS overlay approaches that are flown without monitoring the underlying NAVAID, or flown when the underlying NAVAID is not functioning are considered to be stand alone GPS approaches; therefore the operator, crew and aircraft must meet all the requirements pertaining to stand alone approaches.

This CBAAC deals primarily with the use of GPS for approach, however much of the training information is pertinent to all phases of flight. Additional information on the use of GPS in enroute and terminal area operations is available in the Aeronautical Information Publication (AIP), Aeronautical Information Circular, IFR Approval to use the GPS in Canadian Domestic Airspace and in the AIP COM section.

Background

The GPS equipment now available for aircraft use is far more than a simple enroute and approach aid receiver. They are in fact enhanced navigation computers with databases and managed flight capabilities. There is no doubt that it will revolutionize enroute, terminal and approach navigation and at the same time, significantly change requirements for crew knowledge of the equipment, cockpit coordination and discipline. TC will require operators and pilots to meet a high standard of training, standard operating procedures (SOPs) and crew coordination in the use of GPS as an approach aid. This is essential to guarantee that the present level of safety will be maintained during the period when aircraft operators, air traffic service providers and regulators familiarize themselves with the capabilities of GPS as an approach aid.

GPS Approach Operations

Only holders of AOCs who are authorized by Operations Specification to use GPS for approach may do so.

For Part VII of the CARs operators, a flight crew usually consisting of at least two pilots is required for any aircraft conducting GPS approaches where persons other than the flight crew are carried. Both pilots must have completed all required company ground and flight training in the use of all models of GPS receiver that they will use for approach, and demonstrated competency in the use of those units (or other sufficiently similar models).

Additional equipment, training, checking and currency standards apply to Part VII, Subpart 703 (Air Taxi) of the CARs operators conducting single-pilot GPS approaches where persons other than flight crew are carried.

Evaluation of GPS Approach Procedures

An evaluation must be completed by an Air Carrier Inspector (ACI) on an operator's use of GPS for IFR approaches, prior to the approval of the operator's GPS approach SOPs (where applicable) and training program. This is in addition to any Aircraft Certification requirements or inspection that may be required as part of the airworthiness installation certification. Evaluations will normally be completed by a Civil Aviation Inspector (CAI) familiar with the operation of the model of GPS receiver, or in cases where the GPS receiver provides input to and is controlled through a Flight Management System (FMS), the model of FMS installed. Identical installations of the same model of GPS in the same type of aircraft with the same operator do not need separate evaluations.

Database - The geographical coverage area for the unit database should be compatible with the type of operations conducted by the company. There must be procedures in place to ensure that the database will be updated in accordance with the appropriate data revision cycle. This should include a contract with a database supplier and the inclusion, in appropriate company manuals, of who is responsible for installing the updates in the aircraft. The company should have a procedure in place for pilots to report database errors and for information on database errors to be passed on to other company pilots, the avionics manufacturer and TC.

Unit Installation and Operation - The handling and procedures associated with the GPS avionics shall be such that all operations required for GPS approach can be accomplished without an adverse impact on normal crew duties and responsibilities. GPS related tasks must not consume the attention of the pilot not flying (PNF) during critical phases of flight (between the time the aircraft turns inbound on the final approach course and the time the aircraft is established in the climb configuration on a missed approach).

Control Display Unit (CDU) and Course Deviation Indicator (CDI)/Distance Display for aircraft types certified for single pilot operation but operated by two crew - The aircraft certification requirements for GPS installed at the pilot position requires: CDI in primary field of view; annunciators in primary field of view; control unit to be adequately accessible and that the Aircraft Flight Manual Supplement include the appropriate limitations and procedures. If the GPS/FMS control unit is not adequately accessible from each pilot position, or if GPS course deviation and distance displays are not within the primary field of view at both pilot stations, it will be necessary to designate (in the company's SOPs and in the Operations Specification authorizing GPS approaches) the position that the pilot flying (PF) and PNF must occupy during GPS approach for that type of installation. An Operations Specification authorizing GPS approaches shall not be issued unless the PNF has an acceptable means of monitoring the PF during an approach.

CDU and CDI/Distance Display for aircraft types that are certified for operation by two crewmembers - shall have GPS course deviation and distance displays at each pilot station. An Operations Specification authorizing GPS approaches shall not be issued unless the PNF has an acceptable means of monitoring the PF during an approach.

Distance Display on the Horizontal Situation Indicator (HSI) - In some installations, GPS guidance information (course tracking, To/From and NAV flag) can be switched onto the HSI for display, but the DME Distance information on the HSI is not switched out (i.e. DME distance rather than GPS distance is displayed continuously on the HSI even when GPS is selected as NAV source for the HSI). For this type of installation, operators will be required to have SOP for GPS approach that prevent the display of distance information, other than GPS distance, on the HSI during GPS approaches. This may be accomplished by de-selecting/de-tuning NAV/DME sources as required to eliminate non-GPS distance displays on the HSI. Display of DME distance outside the pilots primary field of view is acceptable during GPS approach only if the HSI distance display shows GPS distance or is blank.

Annunciation - Responses to system annunciation including Receiver Autonomous Integrity Monitoring (RAIM) warnings, the means of selecting GPS track information to the CDI/HSI and the means of coupling GPS steering information to the aircraft automatic flight control system should be compatible with the safe operation of the aircraft type/category. SOPs shall specify the procedure whereby the control unit is programmed, approach waypoints are verified against an independent source, approach mode is armed, and cockpit navigation source and Automatic Flight Control (AFC) guidance source switches are selected and verified. Any switch selection or programming errors that the CAI believes are likely to occur and that could lead to a serious incident should be identified and addressed in training and in the SOPs if it is possible to do so. If not, then the installation cannot be approved for approach use.

Moving Map & Auto Pilot - For aircraft operated under Part VII, Subpart 3 (Air Taxi) of the CARs conducting single-pilot IFR GPS approaches where persons other than flight crew are carried, these aircraft shall have a GPS installation capable of displaying a moving-map graphical depiction of the flight plan and the instrument procedure, and of being coupled to the auto-pilot for lateral guidance and control of the aircraft during the instrument approach.

Airborne Evaluation - An ACI shall observe the pre-flight and in-flight operation of the unit on at least one GPS approach and missed approach. If the PF is authorized to occupy either seat during GPS approaches, one approach from each pilot position should be demonstrated. An airborne evaluation in an aircraft must take place under Visual Flight Rules (VFR). Emphasis will be on crew coordination, pilot workload (PF and PNF) and switch selections.

Standard Operating Procedures

Where required, the company SOPs must address the use of GPS during approach operations. The crewmember responsibilities with regard to programming, verifying waypoint information from the database, cross-checking pilot-input information and flight plans, activating approach mode, selecting display options to be used and conducting RAIM and/or system status checks must be identified for various stages of flight. The SOPs must minimize the requirement for the PF to manipulate the controls of the GPS or FMS, CDU during approach operations, and ensure that one pilot will maintain a lookout and situational awareness at all times.

Currently CARs 703 single-pilot air operators are not required to have approved SOPs, therefore, they can consider the material above concerning SOPs to be for information only.

Ground Training

For commercial operators, ground training shall be in accordance with the appropriate Commercial Air Service Standard (CASS) for operators certified under Part VII of the CARs. The ground training instructor should complete the manufacturers training program, or demonstrate an equivalent level of knowledge of all functions related to IFR approaches for the unit or units that he or she will be teaching. Where a pilot is required to use more than one type of GPS avionics for approach, companies must address the differences between the units in the ground-training program, unless the units have been determined by TC to be sufficiently similar. Ground training shall include "hands on" training using a synthetic flight-training device, a static in-aircraft unit or other acceptable ground-training device.

A generic GPS approach ground training program syllabus is attached.

Flight Training

Flight training for Part VII of the CARs pilots shall be in accordance with the appropriate CASS. Training shall be completed by a designated training pilot who has completed the approved company ground training program and demonstrated proficiency in the use of the type of avionics to be used for GPS approaches (or avionics determined by TC to be sufficiently similar) to an Approved Check Pilot (ACP). Pilots must complete flight training in the use of GPS for approach and other associated duties, for each crew position they are authorized to occupy. Flight training may be completed in the aircraft where aircraft training and checking is permitted under the CARs or, where simulator training and checking is demanded by the CARs, in a level A or higher simulator equipped with the same model of GPS avionics (or a model determined by TC to be sufficiently similar) that is installed in company aircraft.

Except for aircraft operated under Part VII, Subpart 3 (Air Taxi) of the CARs conducting single-pilot IFR GPS approaches where persons other than flight crew are carried, a minimum of two "stand-alone" GPS approaches should be flown to the prescribed minima for the approach. A missed approach must be flown following one of the approaches.

The following applies for aircraft operated under Part VII, Subpart 3 of the CARs (Air Taxi) conducting single-pilot IFR GPS approaches where persons other than flight crew are carried:

The initial training and checking requirements in a), b), and c) shall be met before being assigned as pilot-in-command (PIC) of a single-pilot IFR operation using GPS for instrument approaches.

  1. Within the preceding ninety days and while under the direct supervision of a designated training pilot (see NOTE below), the pilot shall conduct a minimum of ten (10) GPS approaches:
    1. five (5) of the approaches shall be conducted in actual or simulated instrument meteorological conditions (IMC) to the prescribed minima;
    2. three (3) of the approaches shall include a published missed approach of which at least two (2) shall be conducted in actual or simulated IMC; and
    3. at least two (2) approaches shall be conducted using two (2) different Initial Approach Way Points (IAWPs).
  2. All of the requirements listed in paragraph a) shall be recorded in the pilot's training file and shall include the following information:
    1. registration and type of the aircraft/simulator used for the GPS approaches;
    2. manufacturer and model number of GPS equipment used;
    3. date, name and number of approaches conducted in total, in IMC, with missed approaches and from which IAWPs; and
    4. certification by the designated training pilot attesting to the training given to the pilot.
  3. The pilot shall successfully demonstrate his/her proficiency in GPS operations as part of a Pilot Proficiency Check (PPC) or as a separate check ride conducted by an Approved Company Check Pilot (CCP) or a TC inspector and shall be certified as proficient.

Once initial training and checking requirements have been completed and the pilot is certified as proficient, on going currency requirements shall be demonstrated by conducting GPS instrument approaches during the PPC.

NOTE: A designated training pilot has completed the approved company ground school program and demonstrated proficiency in the use of the model of GPS (or a model determined by TC to be sufficiently similar) to an ACP.

Demonstration of Proficiency

For commercial operators, the demonstration of proficiency shall be done as part of a PPC or as a separate ride by an ACP for operators under Part VII of the CARs. It must be completed on both the PIC and the first officer before they can conduct a GPS approach under IFR.

The check must be done on a simulator approved for GPS approaches and equipped with GPS/FMS avionics sufficiently similar to the company aircraft, if the operator is required to conduct simulator training and checking under the CARs. An aircraft may be used for the proficiency check only if aircraft training and checking is permitted under the CARs. Table top training units cannot be used in the demonstration of proficiency.

The minimum requirement for a proficiency check that is not conducted as part of a PPC is the completion of all pre-flight checks and programming of the GPS/FMS avionics, plus one GPS approach as PF and one GPS approach as PNF. One of the two approaches must result in a missed approach. A Pilot's Check Report form (form 26-0249) will be completed for the items covered and a notation made regarding the type of unit and the proficiency of the candidate, and placed on his company training file (there is no need to forward a copy to TC).

For checks conducted as part of a PPC, a notation that the candidate has demonstrated proficiency in the use of the specific model of GPS for approach shall be made on the 26-0249 form. On subsequent PPCs, one GPS approach as either PF or PNF may be requested.

Although this CBAAC applies to stand alone GPS approaches only, an overlay approach may be used in the demonstration of proficiency flight check for GPS non-precision approaches.

Training Records

A record of initial GPS training and checking completed must be kept in each pilot's training file.

Conclusion

This CBAAC details the requirements of an Operations Specification that shall be issued to authorize an air operator to conduct stand alone GPS approaches in IFR, once the following conditions have been met:

  • a successful evaluation has been completed on each aircraft type GPS/FMS model installation for which approach authorization is sought;
  • company ground and flight training programs have been amended and approved; and
  • SOPs (where required) have been reviewed and approved.

The Operations Specification shall identify each aircraft type GPS/FMS avionics authorized for GPS approaches. After initial issue of the Operations Specification, the company can request the addition of extra aircraft types or GPS avionics as required, provided the conditions have been met with respect to the new addition.

 Attachments:

Michel Gaudreau
Director
Commercial & Business Aviation

Commercial & Business Aviation Advisory Circulars (CBAAC) are intended to provide information and guidance regarding operational matters. A CBAAC may describe an acceptable, but not the only, means of demonstrating compliance with existing regulations. CBAACs in and of themselves do not change, create any additional, authorize changes in, or permit deviations from regulatory requirements. CBAACs are available electronically on the TC Web site, at: http://www.tc.gc.ca/eng/civilaviation/standards/commerce-circulars-menu-284.htm.