Part 9 — System Malfunctions


To facilitate the student learning:

  • to recognize a system malfunction
  • to take appropriate action in the event of a system malfunction


It is extremely important that pilots who are operating database dependent navigation equipment be aware that they must be vigilant and monitor the information and guidance that is being provided by their aircraft's navigation systems. Anomalies have been detected which are a result of software problems or a result of the way procedures and information has been encoded into the database of some GPS equipment. These anomalies may be transparent to the user until such time as the aircraft departs from its expected route or path of flight. It is essential that pilots confirm the equipment is going to respond as expected, by comparing the database information with the hard copy procedure in the Canada Air Pilot and other flight information publications. The requirement to make this comparison is specified in the GPS avionics Flight Manual Supplement.

Essential Background Knowledge

Explain how to verify database waypoints. The verification method used is at the discretion of the instructor provided it is effective. An acceptable method is to compare the database coordinates of a waypoint with the coordinates of the waypoint that are published in a flight information publication and then verify other waypoints by bearing and distance from the verified waypoint. Separate waypoint verifications should be carried out for enroute and terminal procedures.

Review the RAIM check and the appropriate actions.

Review the appropriate action for the illumination of a "GPS Integrity" light.

Explain the appropriate action for a GPS receiver power failure.

Advice to Instructors

GPS system performance is such that it may lead students to develop a false sense of security. Ensure that students cross check the system with conventional navigation aids and occasionally give them a system failure to ensure they can smoothly transition to traditional navigation methods.

The student must diligently monitor the performance of their equipment and verify the accuracy of each selected waypoint using current approved hard copy data prior to using their equipment for IFR navigation. If there are any discrepancies between the information in the database and the published hard copy, then the student must ensure they follow the hard copy procedure.

Air Instruction and Student Practice

Some systems have malfunction reports embedded in their databases, if so, have the student retrieve a report and record the information provided.

Completion Standards

The student shall be able to:

  • recognize a system malfunction
  • take the appropriate action in the event of a system malfunction
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