B747 Undifferentiated or Other Model
Flight Crew Last 90 Days 100; Flight Crew Total 15000; Flight Crew Type 3000
Training / Qualification
No Specific Anomaly Occurred All Types
General None Reported / Taken
Human Factors
Sabre flight plan provides magnetic and true courses. For example; between waypoints N63W130 and FANES the Sabre flight plan lists the following courses after immediately crossing waypoint N63W130 going westbound to Fanes:True course- 287 Mag course- 267 Drawing a course on the current navigation chart and applying current chart variation yields the same result. However; upon immediately crossing waypoint N63W130 the airplane IRS steers to an active waypoint FANES and in this case it steers on a displayed magnetic course of 255; 12 degrees in deviation to the flight plan published magnetic course or map drawn and variation corrected magnetic course of 267 to FANES.   This is a consistent problem of the IRS steering to the active waypoint in the airplane.  The IRS does not appear to have current revision magnetic variation software.  The IRS displays a course to active waypoints and flies the course.  Subsequent waypoint courses on the CDU are displayed from the FMS which has it's own magnetic variation database that needs revision.  One is unable to audit aircraft turning to a proper new magnetic course number when passing over a waypoint per ICAO ; Canadian CAA and FAA published recommended practices for not getting lost; causing a traffic conflict or hitting a rock.  Two degrees of deviation has been the accepted government issued standard for years of long range navigation by all these regulatory agencies; not 12 degrees and more.  This is a much more serious problem navigating farther north than today where magnetic steering course errors well over 20 degrees are common in the 747. Magnetic variation installed in the IRS appears to be about 20 years old when checking magnetic variation historical data for various locations on the globe.  IRS magnetic variation from Honeywell and Boeing in the installed HG 1050 IRS was revised in 2005 and again in 2015 but neither revision appears to be properly installed in the 747 fleet.  Same problems were detected in past years in the 767 fleet.  One is unable to properly audit the aircraft navigation systems with IRS magnetic variation software decades out of current Honeywell and Boeing revision.  The FAA inspector has told me I was supposed to navigate with current revision software and charts and will be violated if not doing so.  He told me I must comply with Ops Specs which has a requirement for current navigation database.  It seems clear that I cannot do this in the 747 provided to me but I have no control over the situation of what looks like IRS magnetic variation database near 20 years old.   I assume on an FAA line check I will not be held responsible for this incorrect situation.   Please have the FAA advise me as such due to an inspector telling me I am responsible for ensuring that current revision navigation resources are in use.  Perhaps a letter from the FAA to all 747 crews advising them that they are not responsible for inaccurate navigation displays would be best?
B747 Captain believes his IRS navigation database (magnetic variation) is out of date as the compass heading being flown between two waypoints in northern Canada does not match the Sabre Flight Plan or the course drawn on a chart.