Part 6 — Approach Procedures

Objective

To facilitate the student learning:

  • to retrieve and arm an approach procedure from the GPS database
  • to execute an approach using GPS

Motivation

Within 20 years all IFR terminal navigation will likely be conducted using GPS as the primary navigation aid. Pilots wishing to fly in this environment will have to have a thorough understanding of the system, its limitations and use.

Essential Background Knowledge

Explain how to transition from the enroute procedures to the approach procedures using GPS for guidance

Explain that approaches must be retrieved from a current database and cannot be created by the pilot inputting waypoints

Explain how to add approaches to the flight plan

Explain how to arm approaches

Explain how to change or delete an approach once added to the flight plan

Explain the various sensitivity parameters of the track bar during approaches and how to confirm that they have changed at the appropriate time

Explain the Technical Standard Order (TSO) C-129 requirement for a Receiver Autonomous Integrity Monitoring (RAIM) check

Explain how to do a RAIM check

Explain what to do if the system fails the RAIM check

Explain the cockpit indications, if any, and what to do if GPS integrity is loss during the approach, before and after the Final Approach Waypoint (FAWP)

Explain how to verify approach waypoints

Explain how to conduct GPS approaches

Advice to Instructors

The transition from enroute procedures to GPS approaches should be conducted exactly the same as for traditional navigation aids. Instructors should emphasize the importance of planning the approach in a methodical and deliberate manner so that the pilot can anticipate and react smoothly to ATC instructions.

Review the AIP Special Aviation Notice dated February 1, 1996 (IFR Conditional Approval of GPS Operations) with the student to ensure he/she understands the certification conditions respecting GPS approaches under IFR and the requirements of TSO C-129.

The accuracy of GPS depends on valid waypoint coordinates. The fact that GPS is used as the source of guidance for approaches makes the validity of coordinates even more important. Almost every pilot who has used area navigation systems can recall database errors. This obviously cannot be tolerated with approach waypoints, so the deliberate verification of waypoints in accordance with direction provided in the GPS Supplement to the Aircraft Flight Manual is essential. At the very least, one waypoint should be verified against the coordinates for the waypoint in a published flight information publication and other waypoints verified by bearing and distance from the confirmed waypoint.

Air Instruction and Student Practice

The student should practice GPS stand alone and overlay approaches until he/she can demonstrate to the instructor that he/she can do the approaches safely and effectively.

Completion Standards

The student shall be able to:

  • transition from enroute procedures to terminal procedures including pre-landing and approach checks, briefings, management of approach aids and adherence to ATC clearance
  • add approaches to the flight plan from the GPS database
  • change or delete an approach that has been added to the flight plan
  • arm approaches
  • describe the various sensitivity parameters of the track bar during approaches
  • conduct a RAIM check
  • understand the certification conditions imposed by TSO C-129 respecting GPS approaches, the operational limitations imposed by the Flight Manual Supplement and the terms and conditions of the Canadian approval to fly GPS approaches (see the AIP attachments)
  • verify approach waypoints against an independent source
  • select and verify cockpit navigation sources
  • select and verify the Automatic Flight Control guidance source switches if equipped
  • establish the aircraft on the required track
  • maintain the track within 1/2 deflection of the track bar
  • maintain published or cleared vertical navigation minima within 100 feet
  • identify waypoint passage
  • execute approaches to minima using GPS for guidance
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