All runways at the Edmonton International Airport are equipped with an Instrument Landing system (ILS) that assist aircraft to safely land.  To ensure accuracy of this equipment, NAV-CANADA completes an ILS inspection twice per year on each runway.  Flight checks involve having a specially equipped CRJ jet aircraft fly simulated approaches to test the accuracy of the navigation signals used by arriving aircraft.  The aircraft will not lower its landing gear and will make repeated approaches to the runway every 5 to 10 minutes.  The duration of a flight check normally lasts 2-4 hours.