Guidance concerning Air Navigation in and above the NAT MNPSA
preferably plotted approximately 10 minutes after passing each waypoint, and, if circumstances dictate, midway between waypoints. e.g. if one system has failed.
Check the present, next and next+1 waypoint co-ordinates as shown on the Master Document against those in the steering CDU before transmitting position reports (in performing these checks review the LRNS stored co-ordinates in expanded Lat/Long format (not abbreviated ARINC 424 format).
Check the LRNS indicated magnetic heading and distance to the next waypoint against those listed on the Master Document.
The procedures outlined in this Section will detect any incipient gross errors, providing that
the recorded/plotted cleared route is the same as that provided by the controlling ATS authority. If there has been a misunderstanding between the pilot and controller over the actual route to be flown (i.e. an ATC loop error has occurred), then the last drill above, together with the subsequent passing of the position report, will allow the ATS authority the opportunity to correct such misunderstanding before a hazardous track deviation can develop. The vast majority of instances of waypoint insertion errors occur when the ATC cleared oceanic route segment differs (partly or wholly) from that included in the filed flight plan or that requested by the pilot. Thorough and diligent checking and cross-checking, by more than one crew member, of the waypoints entered into the navigation computer, against the received Oceanic Clearance would eliminate most of these unnecessary and avoidable errors.
NAT Doc 007